100th Anniversary of Enactment of City Planning Act andBuilding Standard Law

008

010

013

019

Architecture
That Supported
Modernization of
Japan
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029

030

031

032

052

055

056

059

060

100 selectedbuilding technologies
067

069

071

078

An English Summary
096

Edited by: Committee for: “Architecture
That Supported Modernization of Japan”

Published by: The Building Center of JapanThe Japan Architectural Education andInformation Center

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088

Preface

Preface
FUKAO Seiichi Chairperson
2019 marks the 100th year since the enactment of the Urban Building
Law, the predecessor of the Building Standard Law, and of the City
Planning Act.
The Urban Building Law is considered to be the first establishedbuilding legislation in Japan, which proceeded the current BuildingStandard Law after several amendments.
During this period, we have experienced drastic changes occurred in the political and economic sectors and in society as a whole.
Accordingly, cities and architectures also changed, which were supported by the innovation of building technologies. All of these changes
eventually brought about a remarkable reform in our lifestyles.
To shed light on the advancement of building technologies thathave supported modern and current Japan and provided a basis forthese changes, we asked not only architects, but many experts of various disciplines, such as sociology, economics, history, urban planningand journalism, as well, to identify “100 Key Terms” related to Japanese architecture and building technologies. The selected “100 Key
Terms” were classified into five categories: “Housing, “Buildings,“Structural Methods”, Building Production/Facilities” and “Policy/Regional Planning”. We then asked 91 experts who specialize in theseareas to write about the “100 Key Terms” from the viewpoint of a history of the technological progress of construction, newly developedbuilding spaces that resulted from technological progress, and theirinfluences on our lives and on society in general.
“Architecture that Supported the Modernization of Japan – 100
selected building technologies” is a book that was compiled as a publication to commemorate the 100th Anniversary of the enactment of
the City Planning Act and the Building Standard Law.
This English translation of the original Japanese summary of thebooklet was made so that people in other countries might appreciate
the accomplishments mentioned within it.
We will be pleased if the “100 Key Terms” gives you a good overall picture of the Japanese architecture and building technologies thathave been developed over the last 100 years, along with their uniqueness. We hope that the wisdom and ingenuity of the people who created these things becomes evident to all of the readers.

Members of the committee for “Architecture that Supported Modernization of Japan– 100 selected building technologies”

Members of Working Group

Chairperson
FUKAO Seiichi
Members
ASAMI Yasushi
ISO Tatsuo
INOUE Shouichi
EBARA Sumiko
OMI Yasuo
KUMAGAI Ryohei
GONDO Tomoyuki
SASAKI Hiroshi
HAYAMI Kiyotaka
MATSUBA Kazukiyo
MATSUMURA Shuichi
MIISHO Kiyonori

YAMANA Yoshiyuki
YOSHIKAWA Hiroshi
YOSHIMI Shunya

Chief (Operating WG)
OMI Yasuo (cited above)
Professor Emeritus, Tokyo Metropolitan University

Professor, Graduate School of Engineering, Department of
Urban Engineering, The University of Tokyo
Architectural journalist (Executive Officer, Flick Studio Co., Ltd)
Professor, International Research Center for Japanese Studies
Associate Professor, Faculty of Engineering, Chiba University
Professor, Faculty of Engineering, Department of Architecture, Tokyo City University
Associate Professor, Faculty of Engineering, Department ofArchitecture, Tokyo University of Science
Project Associate Professor, Graduate School of Engineering, Department of Architecture, The University of Tokyo
President, Center for Housing Renovation and Dispute Settlement Support
Professor, College of Engineering, Department of Architecture, Nihon University
Professor, Musashino Art University
Project Professor, Graduate School of Engineering, Department of Architecture, The University of Tokyo
Chairman, Japan Federation of Architect & Building Engineers Associations (Professor Emeritus, Shibaura Institute ofTechnology)
Professor, Faculty of Science and Technology, Departmentof Architecture, Tokyo University of Science
Professor, Faculty of Economics, Rissho University
Professor, Graduate School of Interdisciplinary Information
Studies, The University of Tokyo

Chief (Editing WG)
ISO Tatsuo (cited above)

Professor, Faculty of Engineering, Department of Architecture, Tokyo City University

Architectural journalist (Executive Officer, Flick Studio Co., Ltd)

Members
OTAKE RyoOMI Yasuo (cited above)

Managing Director, The Building & Housing Center of Japan. Inc
Professor, Faculty of Engineering, Department of Architecture, Tokyo City University
KUMAGAI Ryohei (cited above) Associate Professor, Faculty of Engineering, Department ofArchitecture, Tokyo University of Science
GONDO Tomoyuki (cited above) Project Associate Professor, Graduate School of Engineering, Department of Architecture, The University of Tokyo
HAYAMI Kiyotaka (cited above) Professor, College of Engineering, Department of Architecture, Nihon University
YAMAMICHI Yuta
Flick Studio Co., Ltd
Observers
Building Guidance Division, Housing Bureau, Ministry of Land, Infrastructure, Transport andTourism
Urban Building Division, Housing Bureau, Ministry of Land, Infrastructure, Transport and Tourism

Members of a round-table talk for “Architecture that Supported Modernization of Japan– 100 selected building technologies”
UTIDA Yositika
OKADA Tsuneo
TATEISHI Makoto
MURAKAMI Shuzo

FUKAO Seiichi (cited above)

Professor Emeritus, The University of Tokyo
Professor Emeritus, The University of Tokyo. Advisor, The
Japan Building Disaster Prevention Association
Former Director of Housing Bureau, Ministry of Construction. Former President, The Building Center of Japan
Professor Emeritus, The University of Tokyo. President, Institute for Building Environment and Energy Conservation(IBEC)
Professor Emeritus, Tokyo Metropolitan University(as of end/March 2019)

C2

100 SELECTED BUILDING TECHNOLOGIESOverview

Overview:

Modern and Contemporary Japan
Supported by Architecture
For this booklet, 100 key technical terms were selected in order to holistically review the progress of Japanese architecture and building technologies over the last 100 years. Each selected
technology was developed and introduced to materialize buildings required of the respective
time. There have been many cases, on the other hand, when structures built with new technologies had a significant impact on society, which eventually brought about important socialchanges.
We have roughly classified the 100 technologies into four periods over the last 100 years,
in order to reflect the historical changes of technologies. This was done with a view to clarifying
what society expected from architecture and buildings in each of those periods, and what thesebuilding technologies provided for society. Please note that this classification of technologies is
not limited to the four periods, as some of the technologies have been in use for a long time.

Part 1

1868–1935

Establishment of Modern Japan and Building
Technologies
Beginning in the modern Japan, Japan proceeded to establish a modern nation, under the slogan of “Enrich the Country, Strengthen the Army”, following the development of the U.S. andEuropean nations as models. This also meant to establish cities which were not in the least inferior to those in the Western nations.
Modernization of urban areas, as seen in the fields other than urban development, beganwith advanced technologies that were adopted by Japan through the efforts of a number offoreign professionals employed by the Japanese government, and of Japanese students sent toWestern countries to study. After the 1900s, Japan gradually modified these imported technologies to make them more suitable for Japanese culture, and situations unique to Japan, andeventually developed its own technologies and applied them to practical applications.
In this period, many government buildings and cultural facilities were built using thesemodern building technologies as symbols of the modernization of urban cities.
In accordance with industrial development, business activity increased dramatically, andmany financial and commercial systems were developed, which required construction of modern buildings in urban areas as centers of business activities. To respond to the need for suchbuildings, innovative technologies became indispensable, such as reinforced concrete structures, steel structures, elevators, and technologies related to electric equipment, lighting appliances and so on.
Also, an increasing number of people started working for newly established companies inurban areas, who, together with military officers and government officials, formed a new social
stratum. For these people, a new style of housing was provided in areas such as residential
suburbs, which were equipped with newly developed facilities, such as modern kitchens andflush toilets.
The economic growth of the period enriched people’s lives, which led to increased consumption and more opportunities for recreational activities. Commercial and entertainment
centers were developed to satisfy people’s needs and new types of buildings, such as a stationbuilding with a shopping center, were constructed.
Prevention of infectious diseases was one of the most serious issues that was addressedby urban policies in Western nations, and so it was in Japan, which led to the introduction ofmodern medicine. For buildings, the importance of a good hygienic environment was recognized, which facilitated the improvement of toilets and provided rat-proof measures to preventthe plague. These efforts, along with improved medical services, people’s awareness of sanitation and better nutrition, resulted in the successful reduction of the number of deaths due tocholera, dysentery and the plague, which had been prevalent in Japan until the beginning of the20th century. [Fig. 1]

01

100 SELECTED BUILDING TECHNOLOGIESOverview

The Great Kanto Earthquake occurred in
1923; the first large disaster to hit Japan after
Dysentery
Plaguemodernization. This had a huge effect on
Cholera(on the left scale)(on the right scale)
160,000(on the left scale)building technology. Since the beginning of600
the modernization, Japan introduced Western style building techniques, mainly the
140,000
brick-structure method, which, however, did500
not secure sufficient strength against large
earthquakes. Since then, many other struc120,000
tural methods have been adopted, such as areinforced concrete structure, a steel struc400
100,000
ture and a steel-encased reinforced concrete
structure, together with seismic design technology. The effectiveness of seismic designs
80,000against earthquakes was proved through the300
experience of the Great Kanto Earthquake,and in 1924, seismic design provisios were
60,000incorporated in the Japanese building stan200
dards for the first time, which were called the
Enforcement Regulation of Urban Building
40,000Law. This provision can be said to be a significant result of the development of modern
100
20,000building technologies that had been accumulated in Japan since its modernization, which
was praised as the world’s leading building
00
regulation at the time.
After the Great Kanto Earthquake, theFig. 1—Change in Number of Deaths by Infectious Disease
most
seriously damaged building structure—
Many lives were lost before the middle of 20th century in Japan by infectious disease, which were rampant due to poor health
was a post-and-beam wooden structure. The
standards and poor hygiene.
number of completely collapsed buildings[Source: Infectious Disease Statistics, compiled by the Ministry of Health, Labor and Welfare]
was 130,000. From this experience, installation of diagonal braces was found to be effective in enhancing structural strength against earthquakes. This was stipulated in the building
standards and is now used in all wooden housing.
Historically, urban areas of Japan, where most of the buildings are of wooden structure,
have suffered a number of conflagrations. In the Great Kanto Earthquake, as one example, mostof the deaths were due to large fires. In view of this fact, lath-mortar construction, which was afireproof technique for wooden housing, became the prevailing method for the fireproofing ofwooden housing.
Additionally, “Dojun-kai”, a public housing corporation that was established for the rebuilding of housing after the Great Kanto Earthquake, played a large role in the construction of multiunit residential buildings, which were well received by the masses.

Part 2

1942

1940

1938

1936

1934

1932

1930

1928

1926

1924

1922

1920

1918

1916

1914

1912

1910

1908

1906

1904

1902

1900

1898

1896

1894

1892

1890

1888

1886

1884

1882

1880

persons

1878

700

persons

1876

180,000

The War - Slumped Period of Building Technology

1935–1955
The prolonged Sino-Japanese War, followed later on by the Pacific War, had a huge influenceon building technology in Japan. Supply of all materials was strictly controlled by government,
as they were needed to produce military supplies, which severely constrained the developmentof building technologies. Thus, provision of housing for the labor force became a problem, suchas for coal miners. This issue continued after the Wold War II, when a priority production systemwent into effect.
The most critical subjects of research and development in this period were an air defense
technology and a system to prevent conflagration in urban areas in order to mitigate the damage caused by the war. This research regretfully did not produce effective results during the war
but yielded great results after the war in regard to preventing extensive urban fires.
Throughout the country, a number of cities were burned to ashes during the war, which
created a housing shortage of 4.2 million units . Moreover, there was a severe shortage of building materials, such as wood, due to an acute demand for rebuilding on the destroyed property,
including industrial facilities. This period may be considered to be the most difficult time forbuilding technology in Japan. Under such circumstances, efforts were made to overcome thisdifficulty by developing building techniques such as designs for minimal houses and alternativebuilding materials including bamboo-reinforced concrete.

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100 SELECTED BUILDING TECHNOLOGIESOverview

Part 3

1955–1990

Building Technologies Supporting Economic Growthand Affluent Living
In 1955, when the first stage of restoration activities was almost completed, the Japanese economy recovered to reach the peak level before the World War II, which occurred in the latter halfof the 1930s. An economic white paper that was produced in 1956 noted that, “It is not the
post-war period anymore”. The Japanese economy entered a full-fledged growth period, whichbrought about great changes in society. In the building sector, engineers were faced with thechallenge of innovation in building technology.
Economic growth brought about a vast demand for building construction, which was intended to create new concepts of space and of town planning. To satisfy the demand withlimited time, labor and material resources, a variety of technologies were developed to rationalize building production and construction processes.

Large Supply of New Style Housing70

14,000persons%

Percentage ofthree metropolitan populations
to the total population(on the right scale)

12,00060

50

10,0008,000

40Total population(on the left scale)

30

6,000

4,000

10

0

2000

1995

1990

1985

1980

1975

1970

1965

1960

1955

1950

1945

1940

1935

1930

1925

1920

2,000

0

20

Population inthree metropolitan areas
Tokyo, Saitama, Chiba, Kanagawa,
Aichi, Kyoto, Osaka and Hyogo prefectures(on the left scale)Fig. 2–Change in Total Population and Three Metropolitan
Populations with Ratio–
The Japanese population increased by 2.3 times in 80 years.
In the three metropolitan areas, it increased by 3.6 times,
which made the supply of housing a big social issue.
[Source: National Census, compiled by the Ministry of Internal Affairs and Communications]

200

100

units

m2

180

90

160

(on the right scale)

Housing starts(on the left scale)

2014
2016

2010

2006

0

2002

0

1998

10

1994

20

1990

20

1986

40

1982

30

1978

60

1974

40

1970

80

1966

50

1962

100

1958

60

1954

During the period of rapid economic growth, expansion of tertiary industries was remarkable,
especially in large cities, where the number of office employees was increasing drastically. Numerous office buildings were constructed, which led to the development of skyscrapers.
In line with the advanced IT technologies that emerged later, a new type of office building,referred to as “an intelligent building”, was developed. The latest IT technologies were adopted
for the building functions.

70

120

1950

Economic Growth and Demand for Offices

80

Average floor area

140

Immediately after the war, the Japanese population was less than 80 million, but rapidly increased to 90 million, by 1956, and in 1967, it reached 100 million. Accordingly, population
concentrations from local areas to large cities had become conspicuous, in line with economic
growth. [Fig. 2, 3] Thus, new technologies were required in order to supply housing to those newurban inhabitants. To address this issue, a new housing policy was formulated that encouraged
land development for large-scale residential projects and development of building technologies
for housing under the initiative of the public sector. This was led by the public sector; Japan
Housing Corporation (currently, Urban Renaissance Agency) and Publicly Operated Housing
Corporations in each region. The private sector also was quite active, and the housing industry
established new housing-supply systems in the form of condominiums and multi-units housing
for rent, in addition to the conventional detached-housing supply.
After the World War II, Japan experienced significant conceptual reformation concerning“family”. One was the nuclear-family trend, and the other was the spread of post-war democracy, which emphasized the importance of the individual and one’s independence. Accordingly, inthe housing sector, new designs were introduced for public housing, based on the idea of “separation of the dining room from rooms for sleeping” and “separation of bedrooms for parerents
and for children”. This basic idea has continued to have a great influence on Japanese housing
to this day.

Fig. 3–Change in Housing Starts and Floor Area of Housing
Unit–
Housing starts surged from the latter half of the 1960s, andthe average housing floor area reached 80m2.
[Source: Housing Starts Statistics, compiled by the Ministryof Land, Infrastructure, Transport and Tourism]

Improvement of Living Standard along with Expanded Consumption
As income levels rose, the demand for more comfortable and a convenient lifestyle grew, which
included modern housing facilities, such as Western-style toilets and gas water heaters, as well
as modern housing that could accommodate such amenities.
The prolonged housing shortage abated in 1973, when the total number of existing housing
units exceeded the number of households, which meant that Japan was at the turning point “fromquantity to quality” of housing. In that period, people’s requirements for housing became diversified, with new needs created in accordance with social change. New systems of housing supply
and residence types were introduced, such as a “Cooperative House” (building co-operatives).
As incomes increased, so did consumption, which facilitated construction of commercial
and recreational buildings in various forms, such as shopping malls and theme parks. New
styles of urban space were created under urban redevelopment projects, which incorporated
mixed-use buildings of offices and residences, and spacious public areas.

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100 SELECTED BUILDING TECHNOLOGIESOverview

Furthermore, an innovative technology that allows for large roofs that were unsupported
by interior columns was developed and put to practical use, which resulted in construction oflarge-scale domes, arenas and exposition facilities to be used for large events.

Buildings as Symbols of Hope
Before the World War II, newly constructed modern buildings were regarded as symbols of the
progress and prosperity of Japan, as well as the dreams of its people. They were dignified government buildings, magnificent office buildings, splendid department stores and theaters,
which formed a spectacular urban scape in the city center.
After the war, however, while values of the Japanese society drastically changed to theequality principle in society, open-design modern architecture that eliminated decorative designs became the dominant style for government and office buildings. On the other hand, buildings used for national events, such as Olympic games and World Expositions, were built withthe contemporary design that represented the era of each event. At that time, peace memorial
facilities and towers were also built as monuments of memories and hopes that are widely
shared by people.
Japan, which had achieved an unprecedented economic growth rate, also pursued advancement in architectural design. Modern Japanese architecture started with learning about,and then introducing, Western style architecture. After that, it went through a unique development process, and a number of structures have been built that are highly evaluated around theworld for their design.

Building Technology Contributing to Economic Growth(Growing Investment for Buildings and Building Technologies)

30,000m2

Others
25,000Public service use

Tertiary industry use
20,000Commercial use
Mining andmanufacturingindustry use
15,000Agricultural/Forestry/Fishery use
Residential/Industrial
mixed use

10,000Exclusive
residential use

5,000

1950
1952
1954
1956
1958
1960
1962
1964
1966
1968
1970
1972
1974
1976
1978
1980
1982
1984
1986
1988
1990
1992
1994
1996
1998
2000

0

Fig. 4–Change in Total Area of Building Starts (classified according to use)–
In accordance with economic growth, the investment forbuildings increased rapidly, especially for those of residentialuse, commercial use and the tertiary industry use.
[Source: Building Starts Statistics, compiled by the Ministryof Land, Infrastructure, Transport and Tourism]

In line with economic growth, investment in building construction increased sharply. In 1960,
the area of building construction starts totaled 66 million square meters, which increased to 267
million square meters in 1973, four times what it was in 1960. Investment in tertiary industries,
i.e., commercial and service industries, as well as the housing industry, showed outstanding
increases. [Fig. 4]
As investment in buildings played an important part in the national economy, more efficient, faster and safer building construction was required, and thus the development of newtechnologies was strongly required to rationalize construction processes. At the same time,safety measures for construction workers also made considerable progress. As a result of thesetechnical advances, the increase in construction laborers (for both building and civil engineering) was only about 1.5 times during this period, in spite of the remarkable growth of construction projects.
Under these circumstances, a shortage of skilled workers became a serious problem, especially in the housing sector, such as carpenters who had long supported the Japanese wooden-housing industry with their superb techniques for constructing traditional wooden structures. Therefore, more efficient housing supply mechanisms and technologies were required,together with the urgent need for a large supply of housing as previously mentioned. This wasachieved by transferring some of the conventional on-site building works to in-factory production processes, where the prefabricated house system and the two-by-four housing systemwere adopted. This, at the same time, evolved into the establishment of a housing industry that
became one of the modern Japanese industries, which developed innovative building systems,
including factories for large-scale housing components. This movement further evolved into a
new phase of technological progress.
Besides building up a large number of housing, securing the quality of housing became anurgent matter. For this issue, the specifications of housing published by the then Government
Housing Loan Corporation played a great role. On the other hand, however, a significant number of defective houses were found at that time, which became a serious social problem. To
cope with this issue, new housing-policy measures were formulated from the viewpoint ofconsumer protection, one of which was the Housing Performance Indication System.

Building Technologies to Cope with Frequent Natural Disasters
While the national economy showed incredible growth, a great number of congested quartersof wooden housing that were built before the World War II and in the post-war period still re-04

100 SELECTED BUILDING TECHNOLOGIESOverview

mained in many cities. Until 1960s, fires often occurred in these areas, creating large urban
conflagrations, These disasters gradually decreased as rebuilding of old wooden buildings were
undertaken, to which new fireproof technologies were applied. Since the 1970s, the number oflarge fires has significantly decreased due to the improvement of firefighting capabilities. However, the risk of extensive fires occurring in urban areas still remains, especially in the event oflarge earthquakes. Thus, the issue of the congested urban areas of wooden buildings still exists
as a challenging issue.
The “Shirokiya Department Store Fire”, in 1932, was the incentive for the formulation of fire
prevention measures for large-scale buildings, and all others that are open to the public. After
that, openining fireprotective assembly was greatly improved, based on the experience of many
fires and the knowledge gained as a result of them. Remarkable progress was seen in the research of fire safety of modern buildings, which allowed for the construction of new building-design methods that helped prevent the spread of fire, and for evacuation during fires.
These technical developments eventually led to the introduction of the performance-based
building regulations/standards and further progress in building technology.
Japan has been hit by a number of catastrophic earthquakes since the Great Kanto Earthquake. Every time a large quake occurs, considerable research is done regarding damage tobuildings. Based on the improvement of structural techniques, the building standards were revised. Furthermore, great advancements have been made in seismic design technology, and theuse of computers for structural design became common. All of this technical progress enabled
the construction of skyscrapers and buildings with large spaces without support columns, bothof which had previously been “the buildings of dreams”. The result of the progress that thebuilding standard reached became the New Seismic Standard.
More recently, innovative technologies such as a seismic isolation system and a responsecontrol system were introduced, with the aim of establishing more advanced safety measures.
As seismic technology improves, it has become a challenge to secure the safety of existingbuildings that were constructed according to the previous standard, which led to the development and diffusion of seismic retrofit building technologies.

Part 41990–

Growth to Maturity: Building Technology Supporting
the Future
After the period of high economic growth, Japan experienced a bubble economy, followed by its
collapse, which caused drastic changes in society and to people’s sense of values. While therapidly aging population and the global environment have become challenging social issues, thebuilding sector was expected to support the coming society by development of new technologies.

Evolution to Diversified Society and Revitalization of Regional Resources
It has been necessary to create spaces where everybody, including the aged and persons withdisabilities, can lead active lives. This requires housing for the elderly and building technologies
such as barrier-free and universal designs.
Regional characteristics should also be an important factor. During the period of high economic growth, it was encouraged to develop every region in a uniform manner, in order to remain impartial. Recently, however, unique regional characteristics that were formed as a resultof the local climate and history have caught on with many people. Accordingly, new building
techniques are currently being explored to support, for example, the renovation and reuse ofexisting cultural resources, such as traditional buildings and streetscapes.

Transformation to Sustainable and Stock-based Society
In the high economic growth period, abundant resources were allotted for the construction ofnumerous buildings. This, at the same time, entailed demolishing the buildings that they replaced, thus creating a vast amount of waste. As social awareness of the global environment
grew, however, the building sector was required to make efforts to realize a sustainable society
through technological progress.
It was during the oil crisis in 1973 when measures of promoting techniques for proper insulation and building energy saving were implemented as resource conservation measures inthe building sector. Since then, building technology has made steady progress, and now, more

05

100 SELECTED BUILDING TECHNOLOGIESOverviewadvanced innovation is expected, such as development of sustainable buildings. Furthermore,
recent research has proved that improvement of the indoor thermal environment greatly contributes to the promotion of people’s health. When looking back on the history of Japan, it is notdifficult to imagine that the remarkable advancement of indoor climate of housing that wasmade in post-war Japan has contributed to the longevity of the Japanese people today. The
improved indoor environment is now anticipated to help reduce the cost to the government fornational health care. As such, the roles and responsibilities expected of building technology
have become further diversified in society.
However, the introduction of new building technologies has brought about some healthhazards, such as asbestos health damage and the sick-building syndrome, for which proper
technical measures were taken for these problems.
Annual industrial waste in Japan totals about 400 million tons, of which 80 million tons
(20% of the total) is from the construction industry, with one-third of that being related to buildings. As effective use of resources and a reduction of waste have been serious issues in all
sectors, including the domestic and industrial areas, it is required to improve technologies forthe re-use and recycling of goods. In the building sector as well, technologies for building renovation and conversion are expected to be further improved, in order to continue using thestock of buildings that has accumulated over the years.
One of the most notable building materials that is expected to contribute to the creation ofa sustainable society is wood. In post-war Japan, the use of wood was highly restricted, due tothe devastation of forests, for which restoration has recently been completed. Currently, the useof wood is rather encouraged, as it is a recyclable material. Innovative technologies to compensate for the disadvantages of wooden structures have been developed, such as fire-resistivet
wooden buildings and large-scale timber buildings. Along with these technologies, new structural evaluation methods have also been formulated, such as structural analysis for traditional
wooden buildings, which are expected to further expand the potential of the usage of wood. It
is expected to continue the efforts to make further progress in the field of wooden construction.
Although a variety of new technologies were introduced for housing construction during
the mass-production era, 40% of newly built housing and 70% of total detached houses havebeen built with the conventional Japanese post-and-beam structure. About half of them werebuilt by local contractors and carpenters as custom-built detached houses. Historically, conventional post-and-beam building techniques have contributed greatly to the remarkable progressof the building sector, as well as to the socio-economic development of Japan. These days,
however, a serious problem has emerged in the wooden housing sector, which is the reductionin the number of skilled workers and the rapid aging of those currently in the field.

Contribution to International Society
The various building technologies introduced in this booklet were developed in response to thesocial needs of each time, which have supported the social progress of the modern/contemporary era of Japan. Some of them were developed in other countries and modified in Japan to suit
the situations here, and some were invented in Japan and developed here.
Making use of these accumulated building technologies, Japan has continued to disseminate building information overseas to maintain communication with the global society. Japan
also has provided technical assistance to a number of developing nations around the world.
In the field of seismic engineering, Japan’s cooperation with the US and other nations has
generated considerable mutual benefits to all parties. A Japanese technology for earthquake
preparedness, which is the world leader of such technology, has made a notable contribution tosafety in other countries.
Japan has also made great efforts to facilitate the formation of international measures toward the global environment issue by, for example, organizing Sustainable Building 2005
(SB05). These efforts are ongoing, by means of the provision of information and technical assistance to various countries around the world.
It is expected that Japan will further contribute to the world community based on experience accumulated in the field of building technology in Japan.
As described above, Japanese buildings and building technology have made progress inline with the development of Japanese society over the last 100 years. The progress of building
technology has made great contributions to various aspects of society, such as the improvementof housing, which is fundamental to people’s lives, the creation of spaces for various social activities, better safety and security in the event of disasters, the enhancement of the level of culture, along with improving people’s sense of value. Additionally, the rationalization of the building
production system has played an important role in the growth of the economy. Still now, efforts
are being made to realize a sustainable and mature society. The progress of building technology
will continue to support society by responding to the issues and requirements of each era.

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100 SELECTED BUILDING TECHNOLOGIES

I

ChapterI

HOUSING
Industrial Development and Population
Concentration in Urban Areas
After the Meiji Restoration, Japan achieved a remarkable level of industrial modernization
through the First Sino-Japanese War and then
the Russo-Japanese War, which brought about
dramatic growth of urban populations. For those
who migrated to urban areas, apartments firstbecame available as high-end, multi-unit residential buildings in the early 20th century. In the
new industrial cities and the surroundings oflarge factories in rural areas, high-density apartment complexes were constructed for the workers, which was best represented by coal miners’
housing [003]. Around the same time, renovationsof slums and substandard houses were undertaken in urban areas as a government measure
to improve deteriorated urban environments.
During this period, railway companies developed residential areas outside of inner cities,
which are called residential suburbs [001], modeled after developments in Western countries.
After the Great Kanto Earthquake, an association named “Dojun-kai” was established as anational restoration program. They constructed
Dojun-kai apartments [002], which were designedwith ingenious layout plans, and were equippedwith modern facilities and common spaces. The
Dojun-kai was also engaged in housing supply,with the objective of improving the quality of
housing in Japan.

HOUSING

Commentary

Post-War Housing Shortage and Standardization/Industrialization

Resolution of Housing Shortage and theFollowing Trend

One of the most serious social issues in Japanafter the World War II was a shortage of housing
units, which totaled about 4.2 million units. In
order to provide an enormous number of housing units with limited materials and human resources within a short period, standardizationand industrialization of housing production andsupply were vigorously promoted. A new housing policy was established, which was called“three pillars of the post-war housing policy”,
i.e., the Government Housing Loan Corporation(GHLC), Publicly Operated Housing Corporations and Japan Housing Corporation (JHC). The
latter two mainly supplied multi-unit residentialbuildings, namely, publicly operated housing
and JHC housing [004], for which standardized
designs and housing components were utilized,
as well as industrialized building techniques andmaterials, such as a pre-cast concrete. Large developments of JHC apartment complexes were
widely referred to as Danchi [005], and an extensive number of new towns [006] were plannedand constructed in the suburbs of metropolitan
areas. Most of the publicly operated and JHC
housings were initially multi-units for rent, however, beginning in the 1950s, supply of condominiums [007] began in urban areas, along withthose supplied by the private sector, which iscurrently the predominant type of housing in Japan. In 1962, the Act of Unit Ownership of Condominiums was enacted, which legally established the rights of unit owners of condominiums.
The other pillar of the post-war housing
policy was the establishment of the GHLC,
whose function was to provide housing loans,mainly for construction of conventional postand-beam wooden houses. It also contributed tothe improvement of housing quality through the
GHLC Specification [014], which was used as thetechnical criteria required to qualify for housing
loans. The industrialization of detached houses
was first attempted shortly after the end of thewar, when some architects designed prefabricated housing [018], which had consequently led
to the construction of minimal houses [013], withan aim to pursue modern living spaces, in spiteof the limited availability of resources. In this period, many non-housing related industries, suchas munitions manufacturers, entered the housing
industry with the intention of a peaceful output of
their industries. In the 1960s, the prototypes oflarge prefabricated housing manufacturers appeared in the industry, which thrives today. The
government also facilitated the industrializationof housing production by utilizing the GHLC loansystem, which was further promoted in the 1970s
by some pilot projects [019], such as a designcompetition for the Ashiyahama High-rise Residential Project and other pilot housing projects.
On the other hand, the concentration of
populations in urban areas that occurred in theera of high economic growth brought about unplanned residential developments, as previously
seen before the war, which eventually led to thecongested districts of small wooden multi-unit
housing operated by private sector [008] in the
peripheries of urban areas, that were called“wooden rent-house belt zones”. There was an
overall trend towards housing standardization,
which however did not conform to the conventional existing local houses, in regard to the respective regional characteristics. One of the typical examples of such local-based housing wascold-region housing [015], which was developedin Hokkaido prefecture.

In 1968, the total number of existing houses exceeded the number of households in Japan. As
the housing shortage problem was statisticallyresolved, the housing issues shifted drasticallyfrom standardization and industrialization to
how to address the diverse housing demands ofthe people. In the 1970s, some attempts at providing “open buildings” were made in order to
respond to the needs of residents, which allowed for flexible designs, through the “infill”
method, by assembling generally distributed
housing components. However, in Japan, thetechnical aspect of separating interior finishingfrom structural members was so emphasizedthat such housing units were established as
skeleton-infill house (base building and fit-out
for housing) [020], which mainly aims to provide
long-life housing. Other attempts to explore new
systems of housing supply and new lifestyles
attracted people’s attention, such as cooperative
house (building co-operatives) [009]; whose residents, in the initial stage, organize a co-operative that is to be involved in the planning, designand operation of the building, and collective
housing [010], which provides some common
spaces, such as a dining room, so that the residents can share some time together every day.
At the same time, the average household thatwas established in the post-war period, consisting of a couple with two children, and which had
previously been the premise for housing design,
now occupies a lower position, both socially andstatistically. Currently, therefore, it is required tosupply housing to meet the diversified needs ofresidents, of which one example is housing forthe elderly [016].
As for the materials and building systems,
while prefabricated housing starts remained at alevel of a little more than 10% of the total number of newly built detached houses in around1980, the majority of existing houses were built
by the conventional wooden post-and-beammethod, thus the quality and rationalization of
conventional wooden houses emerged as an important issue of the housing policy. Under suchcircumstances, a pre-cut technique [021] developed in the 1970s gradually spread throughout
the wooden housing industry. It encouraged rationalization techniques for conventional postand-beam houses, such as factory-fabrication of
structural members. With regard to multi-unit
residential buildings, construction of skyscrapercondominiums [011] started around 1990, which
was technically supported by the developmentof high-strength concrete. Their construction
was accelerated by the trend of people returning
to city centers, as well as amendment of the regulation to allow the construction. Regardless ofdetached or multi-unit housing, people’s awareness of housing quality has continued to beheightened, due to successive earthquake disasters, the problem of defective housing, the oilcrisis, and the energy saving consciousness that
followed. In response to the demand of the people, the Housing Performance Indication System [017] was put enacted in the year 2000. After
experiencing recent natural disasters, including
the Great East Japan Earthquake, it is urgently
required to review production system of emergency temporary-housing and restoration
housing [012] to allow for flexibility, in order to suitthe actual situation of each affected area, suchas aging and declining population.

07

100 SELECTED BUILDING TECHNOLOGIES

100 KEY TERMS

1

Housing Supply System

—

I

001

Adoption of Howard’s “Garden City” idea and the Japanization of it
The “garden city” concept proposed by Ebenezer Howard 120 years ago was introduced to Japan at the end of
the Meiji era. It has been materialized as residential suburbs ever since the 10’s of the Taisho era. The businessmodel of the Japanized “garden city” was to develop residential suburbs in conjunction with railroad construction, in order to generate revenue from train fares in addition to that from the housing project, which would be
used to cover the enormous initial investment of the residential developments. By providing new styles of daily
life facilities and adding new functions to the area, such as inviting educational institutions to locate there, theseresidential suburbs were then developed under the names of “healthy city”, “cultural city” and “college city”. Insome of these suburbs, the landowners jointly implemented extensive land-adjustment projects, which still exist
as high-end residential suburbs.

Residential Suburbs

002

A multi-dwelling building complex as a town, created as part of earthquake recovery effort
Dojun-kai, an incorporated foundation established by the Japanese government for the reconstruction of houses
that were destroyed by the Great Kanto Earthquake, built multi-dwelling buildings of reinforced-concrete (RC)structures in various places in Tokyo, which were called Dojun-kai apartments.
Dojun-kai apartments were designed to harmonize with the surrounding environment, and thus create scenic
street landscapes so that they would be favorably accepted by the masses.
Dojun-kai provided various types of units to accommodate multiple types of households including single-familydwellings and were provided with community spaces for the residents. Around the Dojun-kai apartments, facilities, such as restaurants, public bathhouses, barber shops, clinics, and houses with small shops, were provided
to support the residents, which would allow for the area to function as a town.

Dojun-kai
Apartments003

Housing complexes built by companies as a part of production plan
Housing for coal miners was constructed in direct connection with coal production. It was a part of the necessary facilities for coal production from the viewpoint of the employers. Along with housing, various other living
facilities were provided in large-scale collieries, which made them nearly self-sufficient towns like colonies.
During the World War II, these collieries were actively constructed as one of the national programs, which thencontributed to the economic recovery after the war. Shortly after, however, their economic role ended with therevolutionary change of energy resources. It may be said that coal miners’ housing was a sort of flow-type
housing, which continually wavered as the fortunes of the coal mining industry fluctuated.

Coal Miners’
Housing004

A standard design, which contributed to the modernization of lifestyles
Publicly operated housing and JHC housing contributed to the rationalization and modernization of people’s
lives through the development of a standard housing-design. This design also served as a showcase for housingdevelopment in the private sector. As a result of a survey of people’s lifestyles, the basic requirements for housing units were identified as “separation of the dining room from rooms for sleeping” and “separate bedrooms
for parents and children”. Based on these people’s wishes, a standard design for publicly operated housing,called the “51C Type”, was established in 1951. This became a prototype of a floor plan called a “2DK” (tworooms combined with a dining room & kitchen). Depending on the floor plan, a notational system, which included “nK” and “nDK”, was used for housing supplied by JHC that was established in 1955. As the standard housing design became widespread, standardization of housing design came to be seen as restriction in the 1970s.
Since then, flexible housing-systems have been developed to meet the diversified needs of people.

Publicly Operated
Housing and Japan
Housing Corporation(JHC) Housing

005

The fruit of architectural planning study that supported the living standard of post-war period
After the World War II, one of the serious issues in the building sector was the provision of housing. There werenumerous families who urgently needed housing, due to the destruction from the war as well as the post-war
baby-boom. To cope with this issue, the Japan Housing Corporation (JHC) was established in 1955, which thenconstructed a number of Danchi. (“Danchi” is a large-scale housing complex consisting of multi-unit residentialbuildings, which were mainly supplied by the public sector in Japan.) For the purposes of fire-resistant housing
construction, hygiene and the diffusion of a modern urban lifestyle, danchi were initially built of RC structures,with a floor plan that provided a dining room and bedrooms separately. These units were equipped with a stainless-steel sink and a western-style toilet. This was done in an attempt to create a desirable housing style in the
future through the cooperation of industry, academia and government agencies.

Danchi002

1—Housing Supply System

HOUSING

003

005

100 KeyTerms
08

100 SELECTED BUILDING TECHNOLOGIES

007

100 KEY TERMS

I

001

006

Integrally planned and constructed large-scale residential cities

II

007

010

In post-war Japan, housing construction and urban development were urgently required to cope with the lossof housing during the war and also to deal with the rapid expansion of urban areas occurred afterwards.
To address these issues, large-scale, planned residential developments were carried out, which were called New
Town developments.
After the development of Senri New Town, the first of this type of development which was begun in 1960, a
number of New Towns were constructed throughout the country, following the Senri model of development.
These included self-sufficient emerging urban areas surrounding existing large cities, and also new developments located in rural areas, which were developed aiming at promotion of regional industries.

New Towns

From housing for high income people to that for the masses after booms

Wooden rental housing to accommodate a rapid migration to urban areas

IV

008

Condominiums are supplied and managed under an institution concerning ownership of multi-unit residentialbuildings. They appeared in Japan in the 1950s and were increasingly constructed after the Act of Unit Ownership of Condominiums went into effect in 1962. There were several booms of condominium construction: thefirst one in 1963 and 1964, the second one in 1968 and 1969, and the third one in 1972 and 1973. Through these
construction booms, condominiums were eventually established as a typical residential building in urban areas.
Condominiums in Japan have played an important role in the diffusion and the improvement of mid-high-rise
multi-unit residential buildings of RC structure.

III

Condominiums

Just after the war, the rental housing market was sluggish due to the war damage and also the continuing government control of rent. In the 1960s, the private sector became active in the supply of rental housing.
In the same period, population migration from rural to urban areas increased, which pushed up the demand forrental housing in large cities. It was wooden, multi-unit rental housing that satisfied the acute demand.
There were quite a few wooden multi-units rental housing in unfavorable conditions, which had shared toilets,
shared kitchens and shared entrances. These housing units were phased out after their peak construction period
in 1968.
At that time, the structures of multi-unit rental housing were gradually changed from wooden to non-wooden.
However, the average floor area of each unit remained at the same level, about 40m2.

Multi-Unit Housing
Operated by Private
Sector

A system to avoid the stereotyped housing design of multi-unit residential buildings

Cooperative House(Building co-operatives)

010

A new style of co-living proposed for swaying family modelCollective housing is a multi-unit building whose residents cooperate on some of their daily life activities in ashared space, while still having some privacy.
This type of housing emphasizes the importance of dining together, and thus has a common dining room andkitchen, in addition to individual ones in each housing unit, which is one of the key characteristics of the spatial
design of collective housing.
The pioneer project of collective housing in Japan was one that was supplied as disaster-recovery public housing
for the Hanshin-Awaji Great Earthquake.
In 2003, the most advanced collective-housing project to date, called Kankan Mori, was opened by the private
sector, where residents are sharing the housework, childcare and so forth.

Collective Housing

010

001–010

the Edo era: 1603–1868 / the Meiji era: 1868–1912 / the Taisho era: 1912–1926 /the Showa era: 1926–1989 / the Heisei era: 1989–2019 / the Reiwa era: 2019–09

100 SELECTED BUILDING TECHNOLOGIES

100

Cooperative house is a multi-unit housing system by which a union of residents purchases a plot, places orders
for a building design and construction, and then arranges for maintenance and management activities to be
carried out after occupancy. This type of housing was introduced to Japan in the 1970s, mainly in metropolitan
areas. The advantages to the residents of a cooperative house are that they can purchase the land and the building at the actual price, eliminating an agent fee, and individuals can design their own units. Shortly after the
introduction of cooperative house, residents themselves usually undertook the hiring of a contractor. This, however, has gradually changed; nowadays it is common for a private coordinator to find people to buy into cooperative house projects. Large-scale cooperative house, called “co-op-towns”, have been developed by the public
sector, such as local housing-supply corporations.

V

009

008

1—Housing Supply System

HOUSING

100 KEY TERMS

I

011

Until the early 1970s, multi-unit housing that were built on the outskirts of cities, such as danchi, were all midrise buildings of around five stories.
The era of high-rise condominiums, such as skyscraper condominiums, began in 1974, which was marked by
the construction of an 18-story RC condominium called the Shiina-machi Apartment.
Since the late 1980s, construction of skyscraper condominiums was further accelerated and in the 2000s, thescenery of skyscraper condominiums became a familiar part of the urban landscape.
The construction of these skyscrapers was enabled by an accumulation of technical development in various
fields, including structural technologies, construction site works, and designs for buildings and interior of housing units.

012

From post-war public housing construction to an extensive support for housing
Construction of emergency temporary housing and restoration housing by the public sector have been the core of
housing support for people affected by disasters, which was in line with the post-war government housing policy.
Through the experiences of the 1994 Hanshin-Awaji Great Earthquake and the following several large disasters,
new, extensive housing development measures have been created, in addition to the conventional procedure ofconstructing individual buildings. These include a linkage with various other land development projects, an
adoption of various systems for ordering construction works and building materials, and a re-use of the existing
housing stock.
These attempts may lead to the new housing support system for the future, which will be established based on
the mature housing market mechanism and be designed to best suit each regional circumstance.

Emergency Temporary
Housing and
Restoration Housing
2

Living Standard

013

Aiming at equal rights for habitancy
After the World War I, the possibility of providing “minimal houses” was studied in Europe as a measure to accommodate the vast number of immigrants who flowed into urban areas.
Most of those European minimal houses were multi-unit residential buildings, but those developed in Japan
were detached houses.
To the question “How much affluent living can you provide with a limited floor area and budget?”, many architects answered in various ways with their own design capabilities.
However, in the period of high-economic growth, the significance of “minimal houses” was diversified in accordance with changes of social circumstances.

Minimal Houses

014

A design and construction manual that enhanced housing quality in post-war JapanIn 1950, the Government Housing Loan Corporation (GHLC) was established for the purpose of solving the severe shortage of housing. In order to provide housing with sufficient quality, the GHLC set technical criteria,
which were slightly higher than the level of the Building Standard Law and required the housing to meet thosecriteria as a condition for approving loans for them. This program was implemented in conjunction with thebuilding permit system.
The GHLC Specification is a manual that describes materials and building methods to be used in order to satisfy
criteria so that home builders and craftsmen may properly proceed with building construction.
After a number of amendments, the GHLC Specification still plays an important role in improving the quality ofJapanese wooden housing.

GHLC Specification

015

Technical development of housing that is suitable for cold regions with heavy snowfall
Historically, Japanese houses were built for summer weather. Thus, they were not suitable for cold climates withheavy snowfall, especially that of Hokkaido. After the World War II, therefore, “cold region housing” was developed for the specific purpose of improving the lives of the people of Hokkaido.
Cold-region housing is the fruits of the cooperative efforts in research and development made by a number ofengineers, researchers and administrators in Hokkaido.
These R&D efforts continued after the development of the cold-region housing, which led to the development of
the current energy-efficient housing and Housing for Northern Areas. Cold-region housing provided a basis ofresidences in areas of cold weather with heavy snowfall.

Cold-Region Housing

013

2—Living Standard

Technical development that realized construction of tower condominiums

Skyscraper
Condominiums—

HOUSING

019

100 KeyTerms
10

100 SELECTED BUILDING TECHNOLOGIES

100 KEY TERMS

I

3—Rationalization of Production

HOUSING

I

016

PrefabricatedHousing

Pilot Projects

020
Skelton-Infill House(Base building andfit-out for housing)

021
Precutting

Beginning in the 1960s, the Japanese housing market grew dramatically, which encouraged other industries toenter this attractive market, such as those of iron, steel, chemical, and electric appliances. These industries wereseeking more productive manufacturing and supply systems for housing through industrialization, instead ofcontinuing with the conventional wooden-house building system that relied on traditional carpentry methods.
They had an eye on light-gauge steel material, which had just been put into practical use at that time, and developed housing structural systems utilizing this material. In the same period, other housing manufacturers entered this market who used concrete for the structural material and wooden components for the same. All ofthese new housing systems, called “prefabricated houses”, were flexibly changed and created new styles ofhouses to meet consumer demands, which were gradually accepted into the Japanese housing market.

Linked with changing issues of housing administration of each period
Nowadays, the word “pilot” is commonly used to mean “a person who operates an aircraft”, but it originallymeant “a guide in waters, or a specialist who assists a captain of a ship in guiding it over rough seas”. In thefield of architecture, “a pilot project” means a building project carried out as a test of some unestablished technology to determine whether it is worthwhile to further develop it for a practical application.
In the housing sector, especially, a number of notable pilot projects have been conducted over the years to address issues of government housing-administration.

100

019

Houses produced and supplied in a similar way that automobiles are

V

Rationalization of Production

018

The Housing Performance Indication System is a method of rating the level of performance of a housing unit,
based on standardized criteria, which then indicates the evaluation results.
This system helps homebuyers to compare the quality of housing and also to settle housing-related disputes
when such cases occur after the purchasing. Housing suppliers also find the method to be beneficial in receiving
orders, based on their technical superiority.
With this system, fair assessments have been made on technologies developed by the housing industry, which
contributed to the betterment of the housing market.
Now, this system is indispensable for providing communication between homebuyers and housing suppliers in
addition to creating a quality stock of housing.

IV

3

—

A system for properly evaluating housing technologies

III

Housing Performance
Indication System

021

017

The housing for the elderly that is described in this section refers to a small room of a barrier free design for asingle resident or a couple.
These units are, in most cases, in multi-unit buildings, which provide services such as monitoring, emergency
treatment, daily life consultation, meals and nursing care.
It was in the latter half of the 1980s when the Japanese government began to take measures to provide adequate housing for the elderly, with the implementation of the Silver Housing Project.
Other government programs for senior housing include nursing homes for the elderly, established under the Act
on Social Welfare for the Elderly in 1963, and housing for the elderly with home-care services, which was started in 2011.

011

Housing for the
Elderly

Housing proposed to address the extreme population-aging in Japan

Durable housing with diverse functions and flexibility
For planning of multi-unit residential buildings, a method to separate structural members (the frame/skeleton)from the interior/equipment (infill) has been employed to meet the diversified needs of residents and to allow
flexibility for changes in residents’ member and lifestyles. As a result of many technical developments and therelated regulation changes, multi-unit skeleton-infill housing (base buildings and fit-out for housing) has gained
popularity, as it ensures that residents can continue living in the unit for a longtime.
As the environment and natural resources issues have become increasingly serious, the use of durable frames/
skeletons and flexible infill systems are the ideal responses to the current social requirements.

A technique of processing wood that supported Japanese housing construction
The majority of newly built detached houses in Japan are built with conventional post and beam construction.
Traditionally, those wooden members were made by carpenters using hand tools, but nowadays they are madewith machinery.
Previously, machines were only used for simple processes which has recently become capable of more complicated processes and their abilities are continuously being improved. Thanks to the wide use of precutting techniques, the time and cost required for building houses have drastically been reduced, and the on-site work has
become safer and more efficient.
Precutting is an indispensable building technique, which has supported the Japanese culture of wooden detachedhouses. It is a building technique unique to Japan, which was developed based on the Japanese building module.

011–021the Edo era: 1603–1868 / the Meiji era: 1868–1912 / the Taisho era: 1912–1926 /the Showa era: 1926–1989 / the Heisei era: 1989–2019 / the Reiwa era: 2019–11

100 SELECTED BUILDING TECHNOLOGIESIIBUILDINGS

Public Buildings

ChapterII
BUILDINGS

From the late Meiji period through the Taisho
era, Japan became a modernized nation, which
was brought about in part by the construction ofvarious public facilities. Major styles of publicbuildings that are currently existing already appeared in that period, including governmentbuildings, schools, train stations, hospitals, city
halls, museums and so forth.
As for school buildings [022], the use of agovernment standard-designs formulated at theend of the Meiji era gradually expanded after thewar, quickly addressing the growing demand forconstruction of schools. After 1970, however,some very ambitious schools started to adopt
new building designs for their buildings. Before
the World War II, public cultural facilities [023],
such as museums, art galleries, theaters andconcert halls, were built in large major cities,
which were, in the post-war period, constructedin each prefecture, and then after 1990, many ofthese were built in cities, towns and villagesaround Japan. A standard design for government buildings [024] was established before thewar, which was applied to the majority of prefectural government buildings. After the war, anumber of city/town office buildings were built
in a modern architectural design. These wereconsidered to be symbols of municipalities, notsimply as offices for local administrators.
Architecture as a Symbol
A building is expected to serve as a symbol, besides having practical functions. Religious
buildings and memorials [027] are typical examples, which are built with the most effectivefunction as symbol. A tower [028] is constructed
for broadcasting purpose and is familiar to people as an icon of a city, and also as a monumentthat marks time, as people recall when it wasconstructed. At international events, such as the1964 Tokyo Olympics [029] and the Japan World
Exposition, Osaka [030] in 1970, buildings and facilities designed by notable architects of thetime appealed to the world as profiles of what
Japan was, and what it strived to be. It can besaid that modern architecture [025], which totallyeliminated decorative features from buildings,
was at one time an attempt to reject the idea ofbuildings serving as symbols, which, however,
eventually became a symbolic style of architecture that represented the modern era. Post-modern architecture, which arose from criticism ofmodern architecture, was trying to incorporate
regional features into buildings. Okinawan architecture [026] is typical of buildings that represent this movement in Japan.
Urban Environment
Urban populations have increased dramaticallyover the last 100 years. Various new problems
have occurred due to sudden urban growth.
New technical proposals were made to solvethese problems. One proposition to create safe
and comfortable shopping spaces for people
gathering in city core areas was the arcade [032],
which is a pedestrian street with a roof, and theunderground mall [033], with the intention of transferring an entire aboveground-shopping town
underground. Another example is the stationbuilding with shopping centers [031], combining
facilities for shopping as well as for transportation, which is a type of commercial building developed solely in Japan. In order to secure open
spaces in congested urban areas, a new plan

12

100 SELECTED BUILDING TECHNOLOGIES

Commentary

was introduced to provide public open spaces [035] with an integral design program. Many
pedestrian decks [034] were constructed to provide safe and comfortable walking spaces by
allowing people to avoid automobile traffic intersections.
Urban Renewal
Since 1980s, urban redevelopment [036] projectschemes have been undertaken in major cities inJapan, integrating offices, commercial buildings, hotels and cultural and multi-dwelling
functions into one building complex by greatly
increasing the floor-area ratio. Many new urban
centers have been created through this type of
projects. Urban waterfront development [037]projects were implemented in many cities to renew deserted port areas, which previously had
warehouses and factories, into lively places,
which attracted people from outside the area.
The shopping mall [038], a new type of largescale commercial facility, became popular as analternative to department stores and traditional
shopping centers.
Lively Spaces
Historically, buildings have created vitality in urban areas. Immediately after the World War II, it
was black market districts that firstly recovered
the vigor in burnt-out cities. Later on, these areas were further developed and transformed tothe currently existing downtowns [039]. Later on,in accordance with people’s growing desire forleisure time, various theme parks [041] were developed, where people can experience special
entertainment in an extensive facility, designed
to express a specific theme. Many convention
centers [040] were also built as a new type of urban facility, where people came from far awayfor various purposes, e.g., commercial activities,
exhibitions, cultural exchanges, tourism, etc.,
which contributed to forming new lively spaces.

100 KEY TERMS

II

1—Public Buildings / 2—Architecture as a Symbol

BUILDINGS

I

1

Public Buildings—

022

Rising above a uniform design building to become characteristic regional centers

School Buildings

026

023

022

Construction of school buildings in modern times began in line with the inauguration of a new educational institution in the Meiji era, which was greatly revised after the World War II, and has been further modified from time
to time in accordance with the social environment of the time. For the one-hundred years from the beginning of
Meiji era, efforts were made to standardize school-building design in order to urgently meet a demand for constructing a number of school buildings. During the fifty years after early 1970s, it has been explored to find theways how school buildings may comply with a diversified educational system, may contribute to the fulfillment ofpeople’s lives, and may cooperate with each regional community. Currently, school systems are expected to meetthe demands of issues related to the IT society, combined elementary-junior high school systems, the global environment, promotion of the use of wood in the construction of their buildings and a safe and secure environment.
Japanese school administrations are also required to cope with the current problems of the deterioration of old
buildings and a declining birthrate, together with the aging population. To address these issues, it is expected that
school buildings be suited for multiple functions, including that of being the center of the regional community.

From a place for appreciating others’ performances to a space for expressing your creativity

Public Cultural
Facilities

III

Part of the modernization of Japan included the modernization of cultural facilities, which brought about the construction of public theaters/halls and museums/art museums. Theater/hall buildings initially served as public halls
for meetings and assemblies, and then their use was expanded to include various other purposes, such as music
performances and plays. Then, there appeared new facilities that are specialized in certain types of performances,
and, on the other hand, multi-function facilities and their accompanying technologies were also developed. In thearea of art museums, exhibition rooms called “white cubes”, which were made in order to appreciate modern artwork, have been gradually changed to the places where people may have various spatial experiences that are created by the contemporary art. Public cultural facilities as well have been changed, from being places where people
appreciate others’ artworks and performances to spaces for people to create things and to express themselves.

IV

024

From symbolic design to post-war modernism
Construction of government buildings in the Meiji era started with the adoption of Western designs and building
technologies, and with symmetrical floor plans and façades that emphasized symbolic characteristics. At theend of the Taisho era, most government buildings had a box-type external appearance, similar to office buildings, and were equipped with a tower that exhibited a strong symbolic feature. After the World War II, the ideaof democracy influenced government building construction. Traditional designs that might recall feudalism weretotally renounced, and instead, clear and bright modern designs were sought as an ideal style for governmentbuildings. At the end of the 1950s, a government building-construction boom occurred as a result of the enactment of the Law for Promoting Consolidation of Municipalities, when fifty government buildings were newly
constructed nationwide within three years.

Government
Buildings

V

2

025

Modernism in Japan coinciding with the European movement
Modern architecture is characterized by the utilization of industrial materials, which were generated by the industrial revolution, for the structure and design of buildings, rejecting conventional architecture.
During the 1920s in Japan, “the secession school of architecture” was founded as a pioneer of modern architecture. During this period, the disciples of F. L. Wright grew out of their mentor’s style, trying to pursue modernism.
This movement in Japan coincided with the growth of modern architecture in Europe.
In the 1930s, Japanese architects who studied in Europe came back to Japan and established the era of modern
architecture in Japan.

Modern Architecture026

One of the practices of post-modernism
The Nago city office, completed in 1981, turned out to be a monumental building, deeply rooted in the history
and climate of the region. For the exterior, concrete blocks were utilized, which were commonly used in Okinawa
under the occupation by the U.S. It was equipped with statues of “Shisa”, an Okinawan talisman that wards
against evil; and had a terrace on each floor to provide shade.
Since then, a number of buildings have been built with strong references to Okinawa, its climate and its history.
Okinawan architecture and its steady and persistent improvement have attracted the attention of the world as
one of the greatest achievements of post-modern architecture in Japan.

OkinawanArchitecture

022

024

025

022–026026

the Edo era: 1603–1868 / the Meiji era: 1868–1912 / the Taisho era: 1912–1926 /the Showa era: 1926–1989 / the Heisei era: 1989–2019 / the Reiwa era: 2019–13

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Architecture as a Symbol—

100 KEY TERMS

II

027

A merger of modernism and symbolism
Religious buildings and memorials that represent spirituality had long played the leading part in Japanese architecture.
Since the modern era of architecture, the importance of architecture associated with spirituality has diminished,but the substance of these buildings still remains in the consciousness of architects.
For example, Tange Kenzo successfully achieved a high-level of integration of modernism and symbolism in his
designs of a Christian cathedral and a war memorial museum.
New religions that emerged in Japan after the World War II constructed a number of huge-scale buildings that
adopted advanced structural technologies to enable free and innovative building designs.

Religious Buildings
and Memorials

028

Repeatedly been destroyed by monsters in movies and advertisements
During the 1950s, many shared broadcast-transmission towers were constructed in major cities in Japan, including Tokyo, Osaka, Nagano and Sapporo.
For each tower, an observation platform was provided on one of the upper floors, where many people visitedand enjoyed the views.
Tokyo Tower, which was once the most famous of all the Japanese towers, was said to be a symbol of post-war
restoration and the high economic growth that followed in Japan, which gave hope to Japanese people for aprosperous future.
It was repeatedly featured in movies and advertisements in Japan.

Tower

029

Showcasing post-war restoration with the fruits of engineering knowledge
In 1964, The Olympic Games were held in Tokyo, which was the first time they were held in Asia.
New transportation systems were developed for the Olympic Game, they were: the Tokaido Shinkansen railway
and the Tokyo Metropolitan Expressway together with the Inner Circular Route.
Also, Olympic stadiums and many other facilities were constructed, such as Yoyogi Gymnasium and Komazawa
Olympic Park, whose excellent architectural designs were highly evaluated throughout the world.
It was a great opportunity to showcase, both within and outside of the country, Japan’s post-war restoration andthe globalization of Tokyo, which were realized by achievements in national land-planning, city planning andplanning of buildings.

The Tokyo Olympics

030

An opportunity to experiment with new building-technologies
In 1970, a world exposition was held for the first time in Asia, in Senri Hill, Suita city in Osaka prefecture. At thesite, the organizer and a number of the participating nations and companies exhibited eye-catching facilities andpavilions and competed for the best building design and uniqueness.
Furthermore, many innovative technologies for structures and site works were introduced, such as space-frameand lift-up construction methods, a capsule structure, a membrane structure and an air-beam structure, all ofwhich had considerable impact on the further progress of building technologies in Japan.

Japan World
Exposition, Osaka1970
3

Urban Environment—

031

Super intensively used urban building complexes unique around the world
Hankyu-Umeda station built in 1920 was the first Japanese-style station building that had a department store asa tenant. Since then this type of station buildings spread throughout Japan. In the post-war recovery period, theNational Railway Corporation constructed many station buildings that comprised commercial functions withpublic-private joint financing, which were called “people’s railroad stations”. After the breakup and the privatization of the National Railway Corporation, the new railway companies actively took up development of suchstation buildings, which produced huge projects such as the Kyoto Station Building and Osaka Station City. The
Japanese station building, best represented by Shibuya station, is a multi-use urban building complex that provides networks connecting the station and the surrounding facilities. It is still changing to make a type of building that is rarely seen in the world.

Station Buildings with
Shopping Centers027

3—Urban Environment

BUILDINGS

029

030

100 KeyTerms
14

100 SELECTED BUILDING TECHNOLOGIES

031

100 KEY TERMS

II

4—Urban Renewal

BUILDINGSI

032

A buffer space created by a collaboration of shops along the street

ArcadeII

The word “arcade” originally meant a corridor or gallery covered with a series of arches. Nowadays, arcades
serve as avenues and shopping streets that are covered by roofs.
The origin of the Japanese-style arcade goes back to the sunshade used in the Edo and Meiji eras. The current
style of arcade appeared in the early 1950s, and was constructed until early in the Heisei era, during which thedesign changed every ten to twenty years, influenced by the fashion of the respective period. Now they are often
found in large cities and in regional urban centers.
An arcade, with the colored walkways and the streetlights, is a commonly shared facility which works as animportant element for creating the urban image. It can be said that an arcade is a unique space that connects
private properties with public areas.

027

033

A distinctive Japanese-style development in densely populated urban areas

In the 1960s, an increasing number of accidents involving pedestrians became a serious social problem, whichbrought about the provision of pedestrian lanes above existing roads to separate pedestrians from automobile traffic.
In Kashiwa city, such pedestrian lanes were merged into an urban renewal project, the Kashiwa Station East
Project, which was completed in 1973. In this project, an entrance of the elevated station building, and thesurrounding buildings were linked by an artificial ground, which was the first pedestrian deck in Japan to provide
an overhead walking network for people.
Since then, this procedure has been adopted for many large-scale urban renewal projects nationwide. It is aneffective urban-infrastructure system that is unique to Japan.

Pedestrian Decks

A measure to integrate urban environment contribution and building code deregulation

Public Open Spaces

4

Urban Renewal

036

Creating an urban core for revitalization of cities
In 1969, the Urban Renewal Act was enacted, with a view to facilitating the efficient use of urban land and improving functions of cities.
Initially, this act was mainly applied to projects of consolidating small, dispersed building lots in order to create
urban cores for modernized commercial activities, as well as to improve disaster prevention capability. After thelate 1980s, there was a social trend towards deregulation and inducement of private-sectors to be involved inpublic works, which facilitated the execution of huge redevelopment projects, such as those on the sites of demolished factories, water treatment plants and former freight stations, turning them into multi-function building
complexes that comprised offices, hotels, commercial facilities, cultural facilities and housing.

Urban Redevelopment

032

034

036

027–036

the Edo era: 1603–1868 / the Meiji era: 1868–1912 / the Taisho era: 1912–1926 /the Showa era: 1926–1989 / the Heisei era: 1989–2019 / the Reiwa era: 2019–15

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Public open space is a public space provided on a building site in various forms, such as a sidewalk, a throughpassage, an atrium, a waterside open space, a square open space, etc.
When a building owner agrees to provide a public open space that contributes to the improvement of an urban
environment, some concessions are made by the government to the developer, in proportion to the level of thecontribution. These can be in the form of relaxation of the regulations for floor-area ratio, building height limit,
and others. This system is stipulated in the provision for “specific blocks” in the City Planning Act, and in the
Building Standard Law for a “integral design system”.
Since the 1970s, it has become common to provide public open spaces in skyscraper construction and largescale redevelopment projects.

V

035

—

IV

034

From a pedestrians-vehicle separation system to three-dimensional-space use in urban areas

III

Underground Mall

036

Underground malls typify overpopulated cities in Japan. They are all-weather pedestrian spaces that connect
railway stations and the surrounding buildings, which are still making progress distinctive of Japan.
It was before the World War II when the first Japanese underground mall was constructed, as what was called “aSubway Store”. These were then constructed throughout the country during the period of rapid economic growth.
Their construction was halted when a large fire, the Osaka Sen-nichi Department Store Fire, occurred in 1972,
but the construction resumed in the late 1980s.
There are now many large-scale underground shopping malls in Japan. There is no other country in the worldthat has developed so many underground malls of such enormous scale.

100 KEY TERMS

II

5—Lively Spaces

BUILDINGS

I

037

Taking attractive environment around harbors back to urban areas

Urban Waterfront
Development

038

Safe and comfortable commercial districts developed in suburbs

In the early-modern times, there were places of amusement for people to gather, which were located in the
peripheries of cities.
In the modern age, those amusement functions were drawn into the center of cities, which were further developed and formed downtown areas. In these areas, streets were lined with shops of various exterior designs,
which were pleasing to passersby.
During the period before and after the World War II, the government attempted to develop planned downtowns,
such as the Shinsekai district in Osaka and Kabuki-cho in Tokyo.
Immediately after the war, there emerged many black markets around railway stations, which gradually grewand eventually formed downtowns.

Downtown

Multi-function facilities that accommodate various groups of people

Convention Center

041

The world separated from daily life
Theme Park: a different sphere, apart from daily life, created based on a specific theme, such as an exotic atmosphere, or the history of some country or region.
The name “theme park” originated in 1983 in Japan, when Tokyo Disneyland opened.
Looking back at history, there were similar facilities opened during the 1960s in Japan, such as Nara Dreamland
and Meiji Village Museum.
Going further back to seek the origin of theme parks, it was found that some entertainment facilities and thosefor simulated pilgrimage (visiting one large temple where model buildings of many other temples are constructed in the precinct, so that the visitor may have simulated experience of visiting all the temples) in the Edo era
were operated in a similar way to present-day theme parks.

Theme Parks

040

037–041

the Edo era: 1603–1868 / the Meiji era: 1868–1912 / the Taisho era: 1912–1926 /the Showa era: 1926–1989 / the Heisei era: 1989–2019 / the Reiwa era: 2019–16

100 SELECTED BUILDING TECHNOLOGIES

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There are several types of assembly halls; those for conferences organized by international organizations and academic institutions, for product exhibitions held by enterprises, for sports and entertainment events, and so forth.
It used to be that a different type of building was constructed for each type of event, e.g., those for conferencehall, exhibition hall, sports arena, etc. However, at the beginning of the 1980s, new types of convention facilities
were constructed, which integrated multiple functions into one facility in order to correspond to the needs that
arose from the increasing scale and diversification of events.
As convention centers are efficient tools to attract numerous people from an extensive area, they are expected
to play an important role to vitalize the city who competes with other cities.

V

040

037

IV

Lively Spaces

039

Lively commercial and entertainment centers

041

5

037

In the late 1990s, many shopping malls designed by an American architect, Jon Jerde, were built one after another in Japan.
The technique of creating safe and comfortable shopping spaces, combined with pleasant pathways, was acompletely new approach from the one for conventional shopping centers which had spread across Japan, accelerated by the trend of mass consumption in the period of high economic growth.
Since then, Japanese developers have rapidly caught up and have constructed a number of shopping malls inthe suburbs. However, it is now a challenging time for them, considering the continuously decreasing population.

Shopping Mall—II

Urban waterfront development: The renovation of port areas previously occupied by warehouses and factories
into charming shopping streets and parks where people can enjoy themselves.
This urban development method, which reminds us of the beauty of waterfront area, came into fashion in Japan
10 years later than that when it occurred in the US. It began in Japan with the opening of Kushiro Fisherman’s
Wharf in 1989, which was followed by various developments in major port cities, such as Tokyo, Yokohama,
Nagoya, Osaka, Kobe and Fukuoka.
In the 21st century, constructions of skyscraper condominiums and offices on waterfront property have beenbooming, which made the area draw people’s attention again.

III

ChapterIII

STRUCTURAL METHODSIntroduction of Modern Structures andJapanization

STRUCTURALMETHODSHistorically, wood was the only material used forbuilding structures in Japan. However, since themodernization of Japan, a variety of structural
materials and methods have been introduced,
beginning with brick construction, which
evolved the current building technologies. Then,the first adopted as a modern building material
was a steel structure [043] which was first used in
the latter half of the 19th century but to a limited
extent, and then its use gradually increased inaccordance with the introduction of American
construction methods. Soon after that, in theearly 20th century, a reinforced concrete structure [045] was introduced, which was valued as
an effective seismic structure suitable for Japan,
a quake-prone country. Therefore, a greatamount of theoretical and practical researches
was made on this structure. As there were many
concrete-form carpenters, cast-in place wascommonly practiced for concrete works in Japan. However, while searching for easier, more
economical and efficient construction procedures, a concrete block structure [042] also cameinto use, mainly for housing construction. The
latest invention that was made following thesestructural developments is a steel encased reinforced concrete structure [044]. This was aunique seismic structural method, which became an indispensable technology for construction of high-rise buildings in Japan.
Establishment of Seismic Design andTechnology
The structural technologies introduced from overseas have gradually been improved their seismic
performances in response to the requirementsof this earthquake country. A seismic design
provisions [046] were established before theWorld War II, which is to secure required seismic strength by length of bearing walls. Thesedesign provisions were developed based on theconcept of seismic intensity proposed by Toshikata Sano. After the war, the seismic standard
was drastically advanced through a number ofearthquake disaster experiences, which was followed by amendments to the seismic legislation. Finally, the New Seismic Design Provisions
were created in 1981, which has formed thebasis of the current seismic design. Furthermore, a seismic isolation system [047] was introduced, which is an innovative system to separate buildings from seismic forces; a completely
different system from the anti-seismic structure,
which allows buildings to resist seismic forces
through their rigidity. As another technology to
reduce seismic vibration transmitted to buildings, a response-control [048] technology wasdeveloped, which has increasingly been used fora number of buildings. It is especially effective
as a countermeasure for long-period earthquake
motion of skyscrapers. These new technologies
are applied not only to newly constructed buildings, but also for the preservation of traditional/
cultural buildings and the continued use of existing buildings as well. They are called seismic
retrofit [049] building technologies including seismic isolation retrofit, which allows for the preservation of a building’s design features yet providing protection against seismic activity. Various
other designs and technologies are currently
being developed for seismic retrofit to correspond to the need of the individual building.

17

100 SELECTED BUILDING TECHNOLOGIES

Commentary

Development of Higher/Larger Buildings
While the basic styles of the Japanese building
structure were established, and, on the other
hand, ongoing overseas building information was
continuously flowing into Japan, the possibility
for constructing much larger-scale buildings had
been raised. This technology made remarkableprogress during the post-war growth period, withthe representative example being the Kasumigaseki Building, completed in 1968. This was Japan’s
first skyscraper [050] realized through a thoroughutilization of prefabrication techniques that wereapplied to pursue a safe and efficient construction process. This consequently promoted industrialization of construction projects in Japan. In
accordance with the growing social needs forlarge-span buildings, such as exposition andsports facilities, together with the progress ofstructural technologies and new materials, newstructural methods were developed, which includes the tubular structure [051], the shell-andspatial structure [052] and the membrane structure [053]. Later, a retractable-roof dome [054] wasbuilt that is suitable for seasonal changes, which
is now in common use as sports facilities.
Evolution of Wooden Structures
Since the era of the modernization of Japan, a variety of structural types have been adopted. At thesame time, considerable technological progress
was made to the original Japanese wooden building. Steady advances were made to seismic
technology for wooden housing [055], based on
accumulated research data obtained as a result of
a number of earthquakes. This accelerated the
spread of the application of braces and bearing
walls. Also, wooden fire-preventive construction [058] came into wide use, which was facilitatedby the extensive conflagrations that destroyed
wooden buildings during World War II. A mortar-coated external wall, one of the approved fireproof specifications in Japan, was a typical building element that characterized Japanese post-war
houses. The two-by-four building [057] system wasintroduced to Japan, mainly from North America,
as a new structural method, which was quite different from the Japanese conventional wooden
structure. This structural method was standardized and incorporated into the Japanese building
standards in 1974, which became available without any special approval. The system was mainly
used for detached houses, and gradually became
recognized in Japan due to the simple construction process that is involved and its strong seismic
properties, which is realized through the large
quantity of bearing walls used in this system.
After the war, on the other hand, non-wooden buildings were dominant in urban areas, except for small structures such as houses, in orderto ensure fire safety in modern cities. From the
beginning of the Heisei era, however, various advanced research efforts and the following deregulations made it possible to construct large-scale
timber buildings [060] and fire-resistive woodenbuildings [059], which were being erected more
and more. Since enactment of the revised Building Standard Law in 2000, various attempts havebeen made to enable construction of large-scale
fire-resistive wooden buildings. Among the hugetechnical and institutional progress made towards the establishment of new wooden buildings, a study of the structural analysis of traditional wooden buildings [056] has made notable
progress, which now is a world-leading technology, being utilized for the renovation and restoration of buildings of cultural importance.

III

100 KEY TERMS

1Structural Method—042

In line with Japan’s modernization, “fire resistance” and “seismic resistance” have been ongoing issues forbuilding construction and urban development in Japan.
After the war, there was an urgent need to construct buildings as fast as possible, and at a low cost.
The concrete block structure was widely used to satisfy this housing demand for a certain period after the war
because of its simple construction method that was similar to that of a brick (masonry) structure, applicability ofseismic technology already developed for brick structure, fire resistance property and the reasonable construction cost.

Concrete Block
Structures

Steel structure prevailed due to improved connection techniques and the use of shaped steel
A steel structure in Japan was first used at the end of the 19th century, and its use spread rapidly through theperiod of high economic growth in the 1960s.
During this period, tremendous progress was made regarding the assembly method, from conventional riveted
joint assembly to the use of H-section steel and high-strength bolted friction-joints, as well as in welding techniques. With this structure, a wide range of buildings were constructed, from low- and middle-rise buildings to
skyscrapers which was best represented by the Kasumigaseki building.
After that, the use of square-steel pipe became common, which was followed by CFT (concrete-filled steel tube).

Steel Structures

044

A unique technology, developed in earthquake-prone JapanA steel encased reinforced concrete structure was developed in Japan by combining a steel structure with areinforced concrete structure. The Marunouchi building, which was built at the end of the Taisho era, was constructed with a steel structure and then reinforced after the Great Kanto Earthquake. This was done by covering
the existing steel columns with reinforced concrete to make each of them an integrated structural member. The
head office of the Industrial Bank of Japan was built with a steel encased reinforced concrete structure. Half ayear after its completion, the Great Kanto Earthquake occurred, however, it did not suffer any damage as a resultof the quake, which drew much attention of engineers. The design method of the steel encased reinforced concrete structure was fully established in the 1950s and has been used for high-rise buildings of around twenty
stories, and for the lower floors of skyscrapers.

Steel Encased
Reinforced Concrete
Structures

045

Structure that allows for the design of various building forms
Due to its excellent seismic- and fire-resistive properties, together with the reasonable construction cost, thereinforced concrete structure has been widely used by architects and engineers in modern Japan.
Using this structure, buildings with innovative structural methods were constructed before the World War II,
such as domes and other large-span roofs with vaults.
In principle, it is possible to form any shape of building with reinforced concrete. This has inspired the creativeness of many architects, resulting in various attempts to create novel building forms.
The fair-faced concrete finish, which has nothing applied to it after the forms are stripped, has been preferred
and adopted by many architects for their masterpieces.

Reinforced Concrete
Structures

2

1—Structural Method / 2—Seismic Technology

Structure that supported post-war recovery housing through their fire resistance, seismic
stability and affordability

043

Seismic Technology—

STRUCTURAL METHODS

046

Changed by earthquake disaster experiences and technological developments
The seismic design provisions are structural standards that were established to prevent buildings from collapsing as a result of earthquakes. Different from ordinary structural designs, this design does not exclude the possibility of buildings being damaged in quakes.
In 1923, the Great Kanto Earthquake hit, and in the following year, the Urban Building Law was revised to incorporate seismic design provisions, which was the first such building legislation in Japan.
In the 1960s, construction of skyscrapers began in Japan, for which dynamic seismic-response analysis was
adopted by utilizing advanced computer technologies.
In 1968, the Tokachi-Oki Earthquake caused serious damage to many middle-rise reinforced concrete buildings,
which lead to the formulation of the New Seismic Design Provisions enacted in 1981.

Seismic Design
Provisions

積層ゴム支承

042

044

045

100 KeyTerms
18

100 SELECTED BUILDING TECHNOLOGIES

すべり支承

047
鋼材ダンパー鉛ダンパー
source: The Japan Society of Seismic Isolation

100 KEY TERMS

III

3—Large-scale Buildings

STRUCTURAL METHODS

I

047
Seismic Isolation
Systems

A combination of an elastic frame and quake-energy absorbing walls and braces
Even if a building does not collapse as the result of an earthquake, if its columns and beams have undergone
plastic deformation, the building can no longer be occupied and will eventually be demolished.
Response control was an attempt to prevent plastic deformation of structural members by installing deformablewalls and beams.
To realize this idea, many technologies have been developed, such as a steel-plate shear wall, a viscous dumping wall, a buckling restrained brace, an oil damper and a damper that uses non-oil viscous material.
Another system of this kind is a tuned-mass damper response control device, installed at the top of a skyscraper,
which is effective in securing stability of the building and allowing continuous occupancy, even in strong winds.

042

Response Control

A seismic isolation system is a system that significantly reduces the amount of damage to buildings as a resultof earthquakes. The system equipment is installed between the foundation and the building, allowing it to absorb earthquake energy. It was 1983 when the first seismic isolation system with laminated rubber bearing,which is still in widespread use at present, was applied to a two-story residential unit with a reinforced concrete
structure. After that, the system was applied on an experimental basis to, for example, facilities of construction
companies who were interested in this technology. Its effectiveness was finally verified by the experience of theGreat Hanshin-Awaji Earthquake, and since then, the use of the seismic isolation system has been widespread,being applied to all types of buildings. Currently, the system is used mainly for high-rise residential buildings,
large hospitals and the like. Just recently, its application to detached houses has been increasing.

II

048

The Great Hanshin-Awaji Earthquake verified the effectiveness

051

Seismic Retrofit

Skyscrapers

051
Tubular Structures

The world’s first super-high-rise building constructed in earthquake-prone area
In 1963, the Building Standard Law was revised to abandon the 31-meter building-height restriction. After that, highrise buildings of 60 to70 meters in height were constructed one after another, such as the Hotel New Otani building.
However, the first skyscraper in Japan which exceeded 100 meters in height was the Kasumigaseki Building,which was completed in 1968. This was also the first skyscraper in the world to be constructed in an earthquake-prone area as well as in a region frequently hit by typhoons.
To realize the construction of this building, various technical developments were made in many fields including
city planning, structural design, facilities, materials and site work.
Based on these developments and other technical innovations that followed, the record for the height of a Japanese building has been broken every several years since then.

Structural method that forms towers and other space structures
Steel-tube is suitable as an axial tension member, as it is light in weight and has high resistance to buckling. Whenits production technology was established, it was applied to large-scale towers and buildings with long spans.
In the beginning, branch joints were used to connect steel-tubes by welding. In the 1970s, a system truss using
spherical nodes was developed, which has been widely used since then for roofs of gymnasiums, stadiums,
shopping malls, exhibition halls and airport facilities.
Since the late 1990s, steel-tube welded trusses have again been favored by designers for application to airportand convention-facilities, which realized affluent structural designs utilizing various curved shapes.

049

042–051

the Edo era: 1603–1868 / the Meiji era: 1868–1912 / the Taisho era: 1912–1926 /the Showa era: 1926–1989 / the Heisei era: 1989–2019 / the Reiwa era: 2019–19

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Large-scale Buildings

050

As a quake-prone country, Japan has developed seismic retrofit technologies in parallel with the accumulated
experience resulting from earthquake disasters.
In the Great Hanshin-Awaji Earthquake in 1995, buildings constructed according to the old seismic standard,
which was effective until 1981, were significantly affected.
From this experience, the Act for the Promotion of Seismic Retrofit of Buildings was formulated to facilitate the implementation of seismic retrofit, which led to the retrofit of many schools and other buildings throughout the nation.
There are two procedures of seismic retrofit: one is a conventional method by which the strength and toughnessof the building itself are enhanced; the other is to install a seismic isolation system or a response control system
to existing buildings.

V

3

—

IV

049

Prevalent since the Great Hanshin-Awaji Earthquake

100 KEY TERMS

III

052

From the ancient Roman era, it had been a dream of human beings, as well as a technological challenge forgenerations, to create a large astylar space where people could gather and meet.
The most important technical subject to achieve this end was how to reduce the weight of the structure in orderto realize a reasonable, and at the same time, esthetically pleasing structure, which enabled to create light,
transparent and fluid space.
This basic concept is reflected in a “spatial structure”, which is represented by “shell structure” that utilizes form
resistance.
When overviewing the period from post-war, when shell/spatial structure appeared in Japan, through today,
episodes which marked each time in the history come into our minds.

053

Realization of huge-space buildings, allowing for the use of natural daylight
In response to the increasing needs for large-space buildings, membrane was adopted as a lightweight material
used for tensile structures, which then became the membrane structure.
From the late economic growth period through to the economic bubble time, membrane structure made a remarkable development and a number of characteristic membrane-structure buildings were constructed in Japan.
For the Osaka Expo held in 1970, an air-supported membrane structure, which uses air as a structural material,
was introduced in the US pavilion and the Fuji-group pavilion as temporary buildings.
Since then, many membrane-structure buildings have been constructed throughout the country, mainly for
sports facilities, which can provide huge bright spaces utilizing natural light.

Membrane Structures

054

Competing ideas for roof open/close technologies
In accordance with the commercialization of sporting events which requires accommodation of large audiences, suchas baseball and American football, construction of large-scale sports facilities with retractable roofing was begun.
Japan’s first retractable-roof sports facility was the Ariake Colosseum constructed in 1991, followed by the Fukuoka Dome which opened in 1993.
There are several types of mechanical systems to retract roofs, namely, the rigid-panel type, the frame-mechanism type and the membrane folding-type, with each type having its own different variations.
Unlike ordinary building structures, those with retractable roofs require many moving parts, which create various technical challenges that must be solved in the design stage, such as techniques for waterproofing andrestrictions on the amount of allowable deformation of structural members.

Retractable-Roof
Domes

4

Wooden Structure055

Seismic properties of conventional P&B houses improved through many earthquake experiences
The basic idea of the current seismic design for conventional wooden housing in Japan, namely, the wooden post
and beam structure, is to resist earthquake forces by using load bearing walls installed with diagonal bracing.
In order for the braces to work effectively, it is essential to connect the column head/bottom and edges of thebraces firmly with the appropriate hardware. To secure sufficient level of seismic stability of a building as awhole, it is necessary to provide a required length of bearing walls that are to be placed in good balancethroughout the building.
These seismic design techniques were established over time, owing to the accumulated knowledge from earthquake experiences from the Meiji era. As a result, an increasing number of wooden houses are now seismic
resistant.

Seismic Technology
for Wooden Housing

056

Extract elements of seismic property and change them into engineering model
It is extremely difficult to determine the seismic performance of traditional wooden buildings from an engineering perspective, as they were developed over time by the accumulated experience of carpenters and craftsmen.
In order to conduct structural analysis on them, it was necessary to firstly study the mechanism of resisting
earthquake forces; secondly, to quantify the aseismic property; and finally, to replace them with an engineeringmodel for each type of building structure.
In the 1980s, it became possible to calculate the seismic property elements of structures, such as rotational resistance of joints, column rocking resistance and effects of isolated column with spandrel walls.
It also became possible to conduct collapse analysis, using 3-dimensional frame models, for which validity canbe confirmed by comparison with vibration-test data.

Structural Analysis of
Traditional Wooden
Buildings

052

4—Wooden Structure

Technical challenge of human beings for centuries

Shell/Spatial
Structures—

STRUCTURAL METHODS

055

056

100 KeyTerms
20

100 SELECTED BUILDING TECHNOLOGIES059

100 KEY TERMS

III

4—Wooden Structure

STRUCTURAL METHODS

I

057
Two-by-Four
Buildings

Construction method served as an effective social service system
For housing construction, there are various wooden-frame structural methods that have been developed overseas, whereas in Japan, a unique post and beam method has been used for many years.
However, after 1974, when the two-by-four structure was stipulated in a technical standard for wood frame
construction in the Building Standard Law, this structural method became widespread throughout Japan.
The two-by-four structural method was introduced to Japan not simply as a technique and a building product,
but also as an effective system for providing social services that was common in North American countries.
Nowadays, more than 100,000 two-by-four houses have constantly been constructed in Japan.
II

058

Creating novel structures/spaces using traditional building materials
From ancient times, wooden structures had been a conventional building method in Japan, which was changed
and utilized in various forms to fit the needs of each era. Throughout the history, the possibility of constructing
large-scale timber buildings has been explored for various reasons, notably due to a shortage of building materials during and after the World War II, and later during the economic growth period, with the aim of developing
innovative technologies and the consequent expansion of economic zones. Recently, large-scale timber buildings have been expected to play an important role in the promotion of the use of wood, aiming at better forest
management, the circular economy and fixation of carbon dioxide. The possibility of creating new architecturaldesigns by using large wooden buildings has also been explored. Nowadays in Japan, it is not unusual to findlarge buildings of wooden structures. To realize these building designs, it was essential to develop large-dimension/high-strength engineered lumber and metal joints, to formulate design standards related to fire safety, andto develop advanced structural-analysis technology.

060

052–060

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100 SELECTED BUILDING TECHNOLOGIES

100

Large-Scale Timber
Buildings

After the World War II, construction of wooden buildings was interrupted due to a stringent fire regulation imposed under the government policy of developing cities of non-combustible construction. Being subjected toexternal pressure, the regulation was gradually relaxed in the late 1980s, beginning with approval of three-story
and multi-unit wooden housing construction. In this century, an increasing number of MLIT (Ministry of Land,
Infrastructure, Transport and Tourism) approvals have been issued for wooden fire-resistive construction permits
since the enforcement of the revised Building Standard Law (BSL) in the year 2000. Furthermore, a standard
specification of walls for fire-resistive construction was provided in BSL Notification 2014, and in Notification
2018, those of other principle building parts for the same were provided, which includes floors, roofs and stairs.
As a result, construction of wooden fire-resistive buildings has become realized, which will further expand thepotential of wooden buildings.

V

060

060

Fire-Resistive
Wooden Buildings

Expanded the potential of wooden buildings

052

059

The idea of fire preventive construction was initiated before the World War II as a measure to prevent buildings
from catching fire as a result of air-raids, by using either lath-mortar, plaster, mud, etc. as external wall coverings.
Still after the war, this technique was succeeded and was incorporated in the Building Standard Law as a measure to prevent fire from spreading in urban areas, which had dense concentrations of wooden buildings. Thus,
external walls finished with mortar and non-combustible siding materials were commonly seen in cities, whichbecame an important element that characterizes townscapes of low-rise urban areas.
Fire preventive construction was developed in Japan as performance-based criteria, by which the safety ofbuildings was verified by conducting tests. Japan was the first country to take this approach, which later became a model for fire research in the world.

III

Fire Preventive
Construction

A basic factor that characterizes the view of low-rise built-up urban areas

IV

BUILDING PRODUCTION / FACILITIESRC Structures and Production Technology

ChapterIV
BUILDING PRODUCTION/
FACILITIESHistorically, the wooden structure was the soleconstruction method in Japan. In the beginningof Meiji era, Western-style building structures
were introduced to Japan. First introduced wasbrick structure and brick buildings were deliberately constructed with an aim to develop a fireproof city, but they suffered serious damage inearthquakes. Thus, at the end of the Meiji era,
the reinforced concrete structure was introduced as an alternative fire-resistive building
structure. The first full-scale reinforced concretebuilding built in Japan was the Yokohama
branch office of Mitsui & Co. Ltd., which wascovered with exterior tiles [069] as cladding,which was the first such application in Japan,
and asphalt roofing waterproof [075] was utilized
for its flat roof, which had also just been introduced to Japan. As the reinforced concrete structure came into common use, foundation- andground-improvement [065] technologies were also
introduced, such as the concrete pile.
Cast-in place concrete [061] was, and still is,
a common method of concrete work in Japan.
After the World War II, production capacity ofconcrete was remarkably enhanced, due to new
production facilities, such as Japanese designed
concrete batch-plants and concrete pumps,
which supported the construction boom that
occurred during the period of high economic
growth. On the other hand, pre-cast concrete
products were developed to replace thetime-consuming on-site formwork. These products were reinforced block, which was developed from the Taisho era to the beginning of the
Showa era, and a precast (PCa) concrete [064]that was manufactured after the war. To respondto the massive demand for housing constructionin the thriving economy, especially in the public
sector, PCa was adopted to the standard specifications of JHC and publicly operated housing,which unfortunately led to stereotypical design
houses that looked nearly identical. Also, apre-stressed concrete (PC) [064], especially PCa
crimping structure pre-stressed by post-tensioning, came into wide use in the 1970s for buildings of large spans, such as warehouses, stadiums and bowling alleys.
ALC [073], a type of foam concrete, was developed in Japan as a lightweight and effective fire-resistive material for small- mid-size steel structuresand is now widely used for exterior cladding of
skyscraper condominiums and also for fire-resistive partition walls in all types of steel structures.
Instead of steel-reinforced concrete, bamboo-reinforced concrete [062] was used as analternative material [062] during the war, due to ashortage of iron. Still today, research is being
done to develop a new type of concrete, which
would be reinforced with an alternative material
to steel, such as carbon fiber, in order to preventthe reinforcement from rusting due to neutralization and salinity.
For the exterior finish of concrete structures,tile, stone, brick and mortar were commonly used
before the World War II. After the introduction ofan exposed concrete-finish [063] to the world byAntonin Raymond, his Japanese disciple, Kunio
Maekawa used the same concrete finish for hisbuilding designs after the war, which was in turnused by Tadao Ando, who has designed many
world-renowned exposed-concrete buildings.
Modernization of Housing Equipment/
Materials
From the post-war restoration through the period

22

100 SELECTED BUILDING TECHNOLOGIES

Commentaryof high economic growth, remarkable progress
was made in the design of Japanese housing.
First, concerning hygiene conditions; vault toilet,
which used to be a common type of toilet, wasgradually replaced with a flush toilet. However, thesewage system was not designed for flush toilets,
thus Johkasou systems (domestic wastewater
treatment facilities) [081] was commonly installed,which secured the minimum level of required hygiene. At the same time, the Japanese-type toilet(squat type) began to be replaced by the Western-style toilet [080], which had recently beenequipped with a warm-water rear-wash function.
Thus, the lavatory has been changed from an “unclean room” to a “comfortable room”.
Innovative changes have also been madeto the kitchen as well, through the introductionof the dining-kitchen room, which considerably
reduced the housework assumed by women.
This new kitchen was technically enabled by the
introduction of the stainless-steel sinks [078],
which is mass produced by integral press-molding, which later led to the development of thebuilt-in kitchen unit. Back in the day, the housesof common people in urban areas did not havebathtubs, thus the people ordinarily used publicbath facilities. This changed with the introduction of the gas water heaters [076] and the prefabricated bathroom unit [079]. An FRP (fiber-reinforced plastic) unit bathtub, which was
combined with a washing space, is widely used,
due to the high waterproof quality of fiberglass
and its workability. It was initially made for hotels and multi-unit housing, but it later became
common for use in detached houses. This was
supported by the development of small, but
high-performance water heaters. It should be
noted that the ventilation fan [077] greatly contributed to the innovations of the commode, thekitchen and the bathroom.
Regarding detached houses, new structural types appeared after the war, in addition to
the conventional post-and-beam structure, i.e.,
the prefabricated structure and the two-by-four
structure. For all of these structural methods, various new building materials [074] were increasingly being used as substrate materials, such as
plywood [074], gypsum board, PVC sheet, and soforth. In recent years, however, the use of these
new materials has made it difficult to disassemble and sort out materials for re-use and recycling from those to be discarded, which is currently posing a question regarding their use
from the viewpoint of the re-use and recyclingof building materials [066].
Technologies that Support Building Construction
In the early stages of building construction, a steel
window-sash was commonly installed, which
was replaced by an aluminum sashes [070] after
the war, and at the same time, factory-madesashes became popular. Use of these sashes extended to the housing sector, which eventually
made an important contribution to the demandfor insulation/energy efficiency [087] that was
raised as a result of the oil crisis. With the abolition of the building height restriction in the building standards, increasing number of high-risebuildings and skyscrapers began to appear,
which brought about a boom in the installation of
curtain walls [071] as non-load-bearing cladding.
Accordingly, the progress that was made for glass
used for openings was outstanding, and in the
1990s, glass buildings [072], employing a high-performance heat-reflective glass and a Low-E glass,
took the architectural world by storm.

wooden buildings having been improved, the concern regarding large fires shifted from the spreadof fire in urban areas to fires in large-scale buildings. To prevent such building fires, legal requirements for opening protective assembly [083]were strengthened, which led to the improvement and diffusion of fire doors/shutters.
Workers who historically supported all of thebuilding construction had been suffering in awful
working conditions and in a premodern labor environment. The labor environment improved
though, due to the measures to ensure safety ofworkers [067], which was implemented by GHQ(General Headquarters). The Industrial Safety and
Health Act was created in the 1970s, to which a
number of amendments have since been made.
As a result, the number of fatal accidents involving
construction workers has decreased to one-seventh of the number of a half a century ago.

Production

061

In the last 100 years, tremendous progress has
been made in building production technologies.
Currently, addressing global warming is an issue, along with the aging population and a declining birth rate. As a countermeasure to global
warming, every building constructed from now
will be required to be, to a greater or lesser extent, a sustainable building [088]. Also, under thechronic labor shortage and demands for workplace reform, it is imperative that production efficiency in the construction sector be improved
further. The key issue for improved production is
automation technology, such as construction
robots, for which wide use of BIM [068] (an advanced technology of CAD [068]) is indispensable.

Dramatically advanced by concrete batch plants and pressure pumps in the economic
growth period
Reinforced concrete structures of cast-in-place concrete were introduced at the end of the Meiji era. This method was dramatically improved after the World War II, through the introduction of concrete batch-plants and theadvancement of concrete pressure-pumps and chemical admixtures.
In recent years, high-strength concrete of more than 100N/mm2 compressive strength has become widespreadand is currently used for construction of skyscrapers.
Various other technical developments have been made, such as a self-compacting concrete, which does not
require a vibration compaction process. This evolution has contributed to the creation of architectural masterpieces based on the free ideas of architects.

Cast-in-Place
Concrete

Materials that symbolize hardship in wartime

Alternative Materials,
e.g. Bamboo-Reinforced
Concrete063

A concrete finish developed in Japan that led the way
The world’s first building of exposed concrete is said to be Église Notre-Dame du Raincy (The Church of Notre
Dame du Raincy), completed in 1922, which was designed by Auguste Perret.
Several years later in Japan, Antonin Raymond designed many buildings of exposed concrete, and became
recognized as a world-leading expert in this field.
After the World War II, Tange Kenzo and some other Japanese architects adopted the exposed concrete finish
for the restorations of many public buildings.
Inspired by this trend in Japan, many American architects began using this finish. In this way, the Japanese
exposed-concrete finish had considerable influence on architecture around the world.

Exposed Concrete
Finish062

061–063

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100 SELECTED BUILDING TECHNOLOGIES100

In the period from the Sino-Japanese War through the Pacific War, all Japanese industries and laborers were
under the control of the government, and in the building sector as well, the use of steel, a major building material, was greatly restricted.
As an alternative to steel, building-product manufacturers turned to wood, cement, pottery, synthetic resin andbamboo to manufacture various building products, such as hinges, sash rollers, structural plywood, etc.
Much research was done on bamboo regarding its replacement for steel as reinforcement of concrete structures.
It was said that bamboo-reinforced concrete was used for construction of bridges, bunkers and some buildings,
which, however, is not known whether it is true or not.

V

062

061

Production Technologies in Future061 063

1—

1—Production

III

The progress of electric equipment/lighting appliances [082] has made an enormous contribution to large-scale office/commercial buildings, as well as to other types of buildings. In the
1980s, as the use of computers became very
common, intelligent buildings [086] emerged, installed with LAN and other information circuits,
which are now standard specifications for large
office buildings.
Elevator [084] technology, which is now indispensable for every tall building, was introduced
from the US, and later, when skyscrapers became
common, a high-speed elevator was developed inJapan, which is now a renowned Japanese technology. Since 1970, the district heating/coolingsystem [085] has commonly been employed forskyscrapers and other office buildings.
While buildings became larger and larger,
and with the non-combustible properties of

BUILDING PRODUCTION / FACILITIES

II

IV

I

100 KEY TERMS

100 KEY TERMS

IV

064

1—Production

Structural method that rationalized construction process leading to realization of large-spanbuildings
The precast (PCa) concrete method is a construction method by which pre-manufactured concrete members aretaken to the building site and to be assembled there.
Through this method, mid-rise multi-unit residential buildings were mass produced by using large factory-made,concrete panels. Factory-made columns and beams also came into widespread use, especially for high-rise buildings.
The pre-stressed concrete (PC) method is a construction method that applies stress to concrete by using highstrength steel.
As it is a method to simplify the construction process of large-span buildings, the PC method has been used forthe construction of gymnasiums, stadiums, distribution warehouses, factories and so forth.

PCa Concrete/PC

065

An “unsung hero” that has supported buildings for centuries
Wooden piles are traditional foundation components, and a part of the technique is seen in the pile dwellings in
Switzerland that were constructed before 3000 BC to provide protection from floods.
Up until the 1950s, wooden piles were major components to support buildings from underground. In Japan aswell, pine piles were found in perfect condition when the Old Marunouchi Building was demolished, which
dumbfounded many building engineers.
Since the beginning of the Meiji era, concrete-pile techniques were introduced from France and the U.S. in accordance with the diffusion of reinforced concrete structures in Japan. Concrete piles actually supported buildings in Japan from deep underground as a sort of “an unsung hero”.

Foundation/Ground
Improvement066

Resource utilization technology to realize a recycling society
Technologies to enable the efficient re-use and recycling of limited resources are indispensable for creating a
recycling society.
In the building sector, the reuse of materials is the process of removing some of the building components fromdismantled buildings and use them for other buildings without any processing. In recycling process, on theother hand, materials such as concrete and wood collected at dismantling sites are transported to intermediate
treatment facilities for recycling.
For recycling of building materials, technologies are required for three processes: collection and transport of materials, intermediate treatment to render the materials usable again, and the manufacturing of the final products.

Reuse/Recycling of
Building Materials

067

To prevent fall accidents at construction sites
Until the late 1990s, more than 1,000 workers were killed annually in construction accidents in Japan, which
accounted for 40% of the total number of labor accidental deaths.
The most frequent types of accidents in this industry are the result of workers falling from buildings under construction. To prevent such accidents, enforcement orders and guidelines concerning scaffolds and safety belts
were enacted.
Regarding scaffolds, a prefabricated type was developed and has been widely used in Japan, which is to assemble a building constructing scaffolding using ladder frame and cross brace.
As for safety belts, a conventional body-belt type was used for many years, however, a harness type has become
obligatory in order to secure a higher level of safety of construction workers.

Measures to Ensure
Safety of Workers

068

Drawing system was fundamentally changed in accordance with progress of computers
In the late 1970s, drawings made by CAD, instead of traditional manual drawings, gained popularity among
designers, but there also was a strong objection to this trend.
However, in accordance with progress made in computer technology, the use of CAD drawings became sodominant that it was almost like a prerequisite condition for the design and building construction works. The
method of drawing was overturned with the changes of a concept of “layer” and “content library”.
In the late 1980s, 3-dimensional CAD was introduced, but its use was stagnated due to the collapse of the bubble economy. In the first decade of this century, however, it was reintroduced in a different form, called BIM, andis now about to once again drastically change the system of architectural drawing.

CAD/BIM

064

BUILDING PRODUCTION / FACILITIES

066

067

100 KeyTerms
24

100 SELECTED BUILDING TECHNOLOGIES

069

100 KEY TERMSIVBUILDING PRODUCTION / FACILITIES

2—Materials and Construction Methods

I

2

069
Exterior Tiles

070

ALC

Transparent buildings realized by technique making supporting members inconspicuous
In the 1920s, Ludwig Mies van der Rohe proposed a plan for a building whose entire exterior would be covered
with glass, which was, unfortunately, too difficult to be realized.
In Japan, the introduction of a float-glass manufacturing technique in the 1960s enabled the mass productionof transparent-flat glass.
In order for the support members of glass to be less conspicuous, several techniques, such as the SSG (structural silicone glazing) method, the glass rib method and the DPG (dot point glazing) method, were developed in
the late 1960s, which paved the way for the design of transparent-glass buildings. Combined with eco-friendly
technologies such as double-skin glass, a variety of attractive glass-buildings are being constructed.

High strength concrete light enough to float on waterPrefabricated building components were indispensable for the modernization and industrialization of the building production system during the period of high economic growth in Japan.
ALC (autoclaved lightweight aerated concrete) was developed in Scandinavia, one of the coldest areas in theworld with a long wintertime, as concrete with a high thermal-insulation property. After being introduced toJapan, it was developed to satisfy the specific needs of each era in Japan.
ALC is a mass-produced lightweight precast component that has incredible properties, which have contributed
to the improvement of fire safety in urban areas, as well as the overall habitability of residences.

071

064–073

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100 SELECTED BUILDING TECHNOLOGIES

100

073

“Curtain wall” is normally used as a general term of “non-load bearing wall”, however in Japan, it refers tosystematized exterior walls, often installed in skyscrapers.
After the war, they were adopted for ordinary office buildings. When construction of skyscrapers began, theiruse gradually increased, as technologies were developed to secure high seismic strength and durability of various finishing materials.
Metal curtain walls are prevalent in other countries because of its light weight, but in Japan, the majority ofcurtain walls are of precast concrete with an outer surface of tile or stone.
Recently, new types of composite curtain wall are often used, which are made by combining metal and precast
concrete curtain walls.

V

Glass Buildings

External wall system developed concurrently with skyscrapers

073

072

Currently, aluminum is an indispensable material as a component of building openings.
Before aluminum was introduced by the building industry, steel sashes were used extensively, however, it wasquite natural to shift to aluminum, considering its high performances of manufacturing, processing and durability.
When aluminum was initially used to manufacture sashes, they were made by simply switching the material
from steel to aluminum using the same production system. It was after the development of the closed section
aluminum profiles that aluminum sash became dominant and the age of the aluminum sash industry began.
As the demand for high quality housing increased, the performance of sashes was also improved, and various
types of high-quality, durable aluminum sashes were manufactured, which are now indispensable components
for openings of every type of building.

064

Curtain Walls

A component that drastically improved the performance of building openings

IV

071

Buildings with exterior tiles are very popular and commonly seen in Japan. They give Japanese people an imageof a modern design and the Western style, even though it is not common in Western countries to tile an entire
exterior wall of a building.
Exterior tiles were introduced to Japan along with the modernization of the country. These were favorably accepted by Japanese people, developed through an ingenious idea and became widespread in Japan, later
spreading to other Asian countries.
Peeling has been the crucial problem regarding the use of exterior tiles since they were introduced. Overcoming
such difficulty, buildings with exterior tiles are still popular and being constructed today.

III

Aluminum Sashes

A typical exterior finish that was developed in Japan

II

Materials and Construction Methods—

IV

100 KEY TERMS

074

A wide variety of new building materials have been developed and used for many common wooden houses inJapan. Among them, plywood is representative of wooden building-materials, which are used as finishing material, substrate material, structural panel and also as concrete form-board.
Gypsum, an inorganic material that is used to make gypsum board, has superior fireproof and sound-insulation
properties, excellent workability and is cost effective, which made it widely used as interior materials for ceilings
and walls.
Furthermore, “wooden boards”, a generic term for OSB, particle board, MDF and the like, are also used asmaterials for structural substrates and furniture/woodcrafts.

075

Material for flat roofing that allowed for flexibility of building planar plans
As Japan experiences a high amount of rainfall, housing traditionally had only pitched roofs, which is effective
for drainage. An asphalt roofing technique that was introduced to Japan in the Meiji era enabled construction offlat-roof buildings. Asphalt roofs were welcomed by many building designers who wanted to freely design floor
plan without being restricted by the roof shape.
After the World War II, a new type of high-polymer material was developed, which was used for membranewaterproofing. This was widely accepted in the industry, due to its light weight and the quick installation process.
For pitched roofing as well, a variety of materials were developed and diffused, such as cement-based corrugated sheet, roofing slate, and metal-based materials such as zinc-coated steel sheet and galvalume steel sheet.

Waterproofing for
Roofs

3

Equipment and Environment

076

Hot-water supply system developed to respond to the needs of the times
When RC multi-unit residential buildings began to be constructed, the bathtubs installed in each housing unit
had a problem with the flu gas exhaust, which was solved by the development of the BF type (closed and balanced flue type) bath boiler. This new equipment helped secure the safety and comfort of urban workers, who
supported the sharp growth of the post-war economy in Japan.
Further efforts of seeking a more convenient, comfortable and safer lifestyle led to the development of the RF
type (rooftop flue-type) water heater, which is unique to Japan.
Necessitated by the oil crisis and the global trend toward environment protection that began in the late 20th
century, more efficient water heaters, like Eco-Jaws and Ene-Farm, were introduced in Japan.

Gas Water Heaters

077

Equipped first in kitchens, then for toilets and in bathrooms, and finally all around the house
Ventilation fans became common in Japanese housing since Japan Housing Corporation (JHC) adopted themfor the rental housing units, which were first constructed in the 1950s. They were provided for the purpose of
preventing condensation and mold.
During the 1960s, ceiling embedded ventilation fans were developed, which exhausted the air through a duct system.
This ventilation system enabled to make floor plans that locate damp rooms, such as kitchens and bathrooms,
in the center of the housing unit, which does not face outside.
In the late 1960s and thereafter, Japanese housing became more and more airtight. To correspond to this, acontinuous (24-hour) ventilation system was developed, and more recently, higher-quality ventilations systems
combined with heat exchangers have appeared on the market.

Ventilation Fan

078

A leading product for kitchen innovation that changed the image of home life
The lifestyle innovation that occurred in post-war Japan might be symbolized by the change to the kitchen design, with a stainless-steel sink placed in the center. Until the 1950s, most sinks were made of materials such as
some metals that easily became rust stained, artificial stones or concrete. Production of stainless-steel sinks had
already begun at that time, however, they were still high-end products, thus not affordable for most people. It
was Japan Housing Corporation (JHC) that disseminated stainless steel sinks. Their first application was in the
Harumi Danchi project that was completed in 1958, in which Hamaguchi Miho, the first female architect in Japan, was deeply involved in its design. In the background of this innovation, there was an important contribution
made by a company that achieved mass production of stainless-steel sinks through extrusion molding press.

Stainless-Steel Sinks

077
source: Panasonic Ecology Systems Co., Ltd.

3—Equipment and Environment

Products in widespread use, due to their excellent performance, workability and cost effectivenessPlywood/New
Building Materials—

BUILDING PRODUCTION / FACILITIES

078

080

100 KeyTerms
26

100 SELECTED BUILDING TECHNOLOGIES

081
source: Ministry of the Environment Government of Japan

100 KEY TERMSIVBUILDING PRODUCTION / FACILITIES

3—Equipment and Environment

I079
PrefabricatedBathroom Unit

Environmental equipment that contributed to living standard improvement and aqueous
environment preservation
Development of Johkasou system (domestic wastewater treatment facility) enabled to install flush toilets even inareas where sewage systems are not available, which played an important role in improving people’s lives. At
first, a single-sewage treatment Johkasou was used, which treated only wastewater from commodes. This has
been replaced by a multi-sewage treatment Johkasou system, which is a tank that treats sewage from commodes, as well as general household wastewater, including those from kitchen, washing, bathing, etc. It may besaid that the role of Johkasou system changed from sanitary equipment to an environmental protection system,
as it has greatly contributed to the preservation of the aqueous environment. The Japanese term, Johkasou, isnow used overseas in reference to this unique equipment that was developed in Japan for wastewater treatment
of individual households.

074

Johkasou Systems(Domestic wastewater
treatment facilities)

It was about 100 years ago when the first Western style flush-water toilet was manufactured in Japan.
At that time, this type of toilet was not widely accepted by people, however, it suddenly became popular since
the Japan Housing Corporation (JHC: established in 1955) adopted this toilet as its standard specification.
Currently, almost 100% of toilets delivered by Japanese manufacturers are Western style ones.
It is characteristic of Japan that almost 80% of housing are currently equipped with a warm water washing toilet,
called “Washlet”.

IV

081

Is the Japanese-style toilet now an endangered species in Japanese housing?

III

Western-Style Toilet

It is required for bathrooms to have properties of waterproofing, damp proofing, water resistance and fireproofing, except of course for the water supply and drainage systems. Traditionally in Japan, people in highly populated areas went to public bathhouses, and in the case of houses with bathtubs, bathrooms were normally located outside the house or in the corner of the house unit. Gradually, it was required to equip every housing unit
with an individual bathroom, which led the development of prefabricated bathroom unit. This bathroom units
were increasingly adopted to high-rise buildings, including hotels and multi-unit residential buildings. Becauseof the Japanese custom of washing themselves outside of the bathtub, prevention of water leaks was a criticalissue in constructing bathrooms. Development of the prefabricated bathroom unit was the ideal solution to the
problem, and it is now indispensable for Japanese housing.

II

080

Revolutionary component that solved water leaks from bathrooms

083

083
Opening Protective
Assembly

New techniques employed by learning from experiences of conflagrations
In the Urban Building Law formulated in 1919, installation of fire doors/windows was stipulated for parts of exterior walls that are liable to catch fire in buildings that are constructed in Fire Prevention Zones.
After the Great Kanto Earthquake, it was found that the amount of damage by fire was larger than that by building collapse as a result of the quake, which accelerated the diffusion of fire doors/windows and fire shutters.
After the Shirokiya Department Store Fire in 1932, the installation of fire shutters inside of buildings was begun
in order to divide large spaces into multiple fire compartments.
Following two successive fires at large commercial buildings in the 1970s, a smoke/fire preventive shutter wasdeveloped, which is highly airtight and automatically closes when smoke is sensed.

083

074–083

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100 SELECTED BUILDING TECHNOLOGIES

100

Electrical Equipment/
Lighting Appliances

In the trend of Westernization in the Meiji era in Japan called “civilization and enlightenment”, a new age ofelectricity began with the introduction of the incandescent lamp. Improvement of lighting appliances has been
made over the years, together with advancements in creative interior designs of commercial facilities.
In recent years, energy efficient LED has been used as a light source, replacing conventional incandescentand fluorescent lights.
Electrical equipment in buildings is supported by electrical substations, which are equipped with multiple electrical lines and emergency power sources in preparation for power failures.
Electric equipment of the next era will be an innovative integration of hardware, software and human ware withthe aim to achieve an ideal “fusion” of building engineering and electrical engineering.

V

082

From the incandescent light and the fluorescent light to energy efficient LED

IV

100 KEY TERMSBUILDING PRODUCTION / FACILITIES

3—Equipment and Environment

I084
Elevators

Intelligent Buildings

The district heating & cooling system is an intensive heat-source system, which mass produces cold and heatwithin a region and delivers cold water, hot water and steam to multiple users. The pioneering example in Japanwas in the Tokyo Imperial University Hospital, where a district heating and cooling system was installed in 1895.
With this system, steam was delivered to seven wards from a central boiler room, which was called “school-building type district heating”. “Business-type district heating/cooling”, by which heat is supplied by corporations or
individuals other than the user, began in 1966 in Japan with Enzan-Kitamchi Jutaku Danchi in Sapporo city. The
district heating/cooling system was incorporated in the City Planning Act in 1968 as part of the urban infrastructure, and consequently, was approved as part of the public works under the Heat Supply Business Act, 1972.
Since then, it has gradually been diffused throughout Japan.

Introduced in accordance with advancements in information and communication technology

IV

086

Born as an anti-pollution measure and now dispersed as an environmental conditioning facility

III

District Heating andCooling System

As buildings became higher, elevators, which vertically transport passengers in cages, were becoming popular.
During this process, various innovative elevator-technologies have been invented.
These include: an elevator with no machine room developed by minimizing the sizes of winches and control
equipment; a variable double-deck elevator with an improved transportation capacity, which enables operationin buildings with floor heights that are not uniform; and an elevator that can be operated in buildings with aseismic isolation system installed in the middle floors; and an ultra-high speed elevator, exceeding 1000m/min.
There are further efforts taking place now to improve the safety and security of elevators, which are: setting amandatory requirement for each elevator to be equipped with a device to prevent people from being trapped
inside; and improving strength and durability of cables.

II

085

Technological progress of lifts to improve vertical movement of people

In the 1980s, an increasing number of office buildings were equipped with an abundance of electronic appliances, due to the rapidly spreading information and communication technologies, which required upgrades of theelectrical, ventilation and wiring capacities of buildings, as well as consideration for the health of building occupants. Also, the use of computers for digitalized telecommunications together with an advanced sensor technology brought about huge improvements in energy efficiency and optimization of building equipment as well as in
the comprehensive safety of the building as a whole. Liberalization and deregulation of the telecommunicationindustry also had a considerable impact on the planning of buildings. In 1984, the first building to be called an“intelligent building” opened in the US, the excitement of which quickly spread to the Japanese building sector.

084

088
Sustainable Buildings085
source: Japan Heat Supply Business Association

Buildings that contribute to the creation of a sustainable society
At the end of the 20th century, many environmentalists started warning of global environment problems, with aprediction that if the world population and economy continued to grow, global warming and destruction of theecology would further proceed, and thus damaged the basis of human society to the point of no return.
Buildings in the modern era have been developed with a sort of ‘artificial environmental technologies’ whichallow consumption of vast amounts of energy as a necessary antecedent. New approaches for reducing ecological footprints have been explored; from the stage of production of materials, through the period of product use,to the stage of product demolition.

088

084–088

the Edo era: 1603–1868 / the Meiji era: 1868–1912 / the Taisho era: 1912–1926 /the Showa era: 1926–1989 / the Heisei era: 1989–2019 / the Reiwa era: 2019–28

100 SELECTED BUILDING TECHNOLOGIES

100

Insulation & Energy
Efficiency

Japanese building-insulation techniques spread from Hokkaido, the coldest region, to most other areas in Japan. In 1969, a standard for building insulation was established for the purpose of reducing costs for heating, as
well as preventing surface condensation on buildings. After the first oil crisis in 1973, energy conservation became a serious social issue, and in 1980, an enforcement order under the BSL was enacted that provided insulation standards for housing together with their design and construction guidelines in order to facilitate energy
savings of housing. Since then, installation of insulation has been promoted nationwide and its regulations/standards have been amended and strengthened many times to the present day. There are various kinds of insulation materials, which are mainly grouped into two types, fiber-type and formed plastic type. In terms of insulation of windows, double-glazed windows became popular in the 21st century in Japan, which has considerably improved the insulation performance of Japanese housing.

088

087

Essential elements for a sustainable society

V

POLICY / REGIONAL PLANNING

Disaster Prevention

ChapterV
POLICY/REGIONAL PLANNING

Japan deals with many natural disasters. It has
experienced many such disasters in modern
times, and the first of those to occur after theestablishment of the Urban Building Law in1919, was the Great Kanto Earthquake in 1923.
In Tokyo, the most seriously damaged area, thereinforced concrete structure, a new structural
method at that time, was used for the rebuildingof primary schools considering its superior seismic and fire-resistive performances. These werelater called “Fukko Shogakko (Restoration primary schools) [089]”. For wooden school buildings built before the introduction of the reinforced concrete structure, improvement wasalso made for their structure after the Muroto
typhoon hit in 1934.
During the World War II, Japanese buildings that were made with wood and paper werecompletely destroyed in great numbers by incendiary bombs. Reflecting this experience, Japan vigorously promoted the creation of cities
where large conflagrations could be prevented.
One of the measures that was proposed was theconstruction of fire-preventive building zones[090], which were “belts” of fireproof buildings tofunction as firewalls for the city. These were
eventually constructed in nearly 100 cities
throughout the country. This idea was succeeded by the concept of fire preventive zone under
the Disaster Prevention Block Development
Law which was the basis of the current urban-space planning.
Going back to the Taisho era, there had
been many residential districts in urban areasthat were deteriorated, thus, slum-clearance
measures [091] were taken in some districts. It
was not until after the war, however, that extensive measures were taken to address this issue,
when it was acknowledged that the existence ofsuch huge areas of slums seriously impeded thedevelopment of urban areas. Among various
countermeasures, one notable project was“Sakaide Artificial Ground”, developed in 1968,
which was an attempt to create a comfortable
residential environment in collaboration with achallenging type of architecture.
Under the economic prosperity afterwards,
concentrations of people in urban areas became
conspicuous, and cities were fully built-up withhousing. When the Great Hanshin-Awaji Earthquake occurred, in 1995, this congestive-city
problem was suddenly recognized as a serious
social issue. Through this experience, measuresfor densely populated urban areas [092] were established to address the problems related toover-developed cities, and to improve living environments by, for example, providing a sufficient number of open spaces in urban areas.
CultureIn the process of social restoration, problems
arising in line with the economic growth weredemolition of historically significant buildings,
together with the surrounding traditional streetscapes. Various policy measures have been proposed to address this issue which, however, do
not seem to be sufficient. Concepts of preservation/conservation of historic architecture [093]and conservation of townscape [094] still remain
as challenging issues.
On the other hand, when a massive housing supply was urgently required, houses werebuilt in a stereotyped style; all of the same design and with the same materials. When the
housing shortage problem was resolved, pro-

29

100 SELECTED BUILDING TECHNOLOGIES

Commentary

motion began for the construction of regional
houses [095], i.e., houses that incorporated regional characteristics, which was represented by the
HOPE (Housing with Proper Environment) Plan.
Later on, the renovation and conversion[096] of buildings have emerged as new issues
with the mature society and sluggish economic
growth as a background. These are vitally important subjects, as it is now strongly required
to re-utilize existing buildings as social assets.
It is particularly interesting to know thatmeasures taken to address these key issues
have been created by grass-roots activities, rather than by bureaucrats and authorities.
A type of building that is rather peculiar inthis booklet, and also in Japan in general, iscolonial architecture [097]. Before the current national boundary was delineated, Japaneseboundaries used to be extensive, and many cities and buildings were developed by the Japanese people in the areas not within present-day
Japanese territory.
Legal Framework
When considering how to control constructionof buildings that constitute urban spaces, it
gradually came to be realized that the existing
simple restriction of building height limit, which
was provided in the Urban Building Law, was
not sufficient to respond to the social demands
for higher-density accommodation in urban areas and for construction of taller buildings thathas been enabled by advancements in technology. Thus, the concept of floor-area-ratio restriction [098] was thought out.
Later on, demand for building quantity was
satisfied and the quality became an important
requirement, which included barrier-free designs in special consideration for people withdisabilities and for the growing number of aged
people. Then its scope was extended to include
every single person, not only people in need,which is known as universal design [099].
It is said that generally, formation/revisionof legislation tends to follow social movements.
Under such a tendency, the most importantchange of the Japanese building legislation in
the 20th century must have been the introduction of performance-based building regulations/standards [100] from the conventional specification-based standards. This revision wasmade with the aim to ensure that building standards may swiftly reflect technical developments of the time. The revision has had somepositive effects so far and is expected to generate more significant results in the future.

100 KEY TERMS

1Disaster Prevention

—

V

089

Fukko Shogakko (Restoration primary schools) are a group of primary schools that were constructed during thecourse of rebuilding around Japan after the Great Kanto Earthquake.
By applying a design code specifically developed for the schools, these reinforced-concrete school buildings
enabled sufficient fireproof and seismic performances in a short period of time.
Some of the objectives of Fukko Shogakko were implementing the New Education proposed in the Taisho era inJapan and serving as cores of the social education of each region. To this end, these schools were planned tohave multiple functions, which later formed a basic concept of the current “open schools”.

Fukko Shogakko(Restoration primaryschools)

Building shields to prevent fires in urban areas
There are several ways to make a city fireproof; however, in existing urban areas, it is difficult to implement suchmeasures as they would require drastic renovation of the structures of cities. To solve this difficulty, an innovative plan was thought out from the viewpoint of “turning a war disaster into an advantage”, which was development of fire preventive building zones; belts of nonflammable buildings that could prevent the spread of fire,much like shields to protect the city. Fire preventive building zones were usually constructed along main streets.
In some cities, these zones gradually formed shopping streets with stores like row-house, which attracted people to move there, and they eventually became lively city-centers. Fire preventive building zones contributed not
simply to creating fireproof cities, but also to keeping the quality of people’s living and to forming the townscapeas well.

Fire Preventive
Building Zones

091

Improve deteriorated residential areas to create new living environment
It was 1920 in Japan when measures were taken to address the problem of slums as there was a sudden increase of deteriorated residential areas, which was caused by the rapid urbanization and industrialization oflarge cities. In accordance with the Act for the Improvement of Deteriorated Residential Areas formulated in
1927, scrap-and-build style residential redevelopments were implemented, that was; within a district designated
for residential improvement, demolished old houses and constructed a sufficient number of new houses so thatthe existing residents could continue to live in that district. In the economic growth period after the war, deteriorated residential areas were considered to be a hindrance to the development of the city as a whole. Succeeding the previous act, the Act for the Improvement of Residential Areas was formulated in 1960. Based on thisnew act, the Sakaide Artificial Ground in Kagawa prefecture and Motomachi/Chojuen housing complexes in
Hiroshima city were constructed.

Slum Clearance

092

From improvement of the living environment to strengthening disaster preventionDensely populated urban areas have long been a serious problem in the history of city planning in Japan, andmany measures were taken to cope with this issue, including slum clearance.
When the World War II ended, new housing supply programs were carried out in the Kyojima district in Tokyoand some other areas, by which new public housing was provided for existing residents of the area, while rebuilding the deteriorated houses.
After the Hanshin-Awaji Great Earthquake, the function of disaster prevention was considered to be more important than the improvement of the residential environment in densely populated urban areas.
Current measures taken to address the issue include; providing more area for public open-spaces, increasing
floor area in fire-resistive buildings, and providing streets that could function as firebreaks.

Measures for
Densely Populated
Urban Areas
2

Culture093

Formulating legislation for utilizing stock in urban areas
In the period of high economic growth, it was difficult to preserve/conserve historic architecture, as the efficientuse of land had a top priority.
In recent years, however, it has become important to efficiently utilize stock (existing architectural resources),
while carrying out urban renewal projects. Accordingly, various legislation has been formulated to allow for development, and at the same time, the preservation/conservation of existing resources as well.
While the need for preservation/conservation of valuable buildings is growing, new approaches have recently
been taken, such as commissioning local governments to legislate their own regulations to preserve/conserve
historic resources in their jurisdictions.

Preservation/
Conservation ofHistoric Architecture090

1—Disaster Prevention / 2—Culture

A new type of school building, born of the rebuilding after the Great Kanto Earthquake

090—

POLICY / REGIONAL PLANNING

092

093

100 KeyTerms
30

100 SELECTED BUILDING TECHNOLOGIES094

100 KEY TERMS

V

3—Legal Framework

POLICY / REGIONAL PLANNING

I

094
Conservation ofTownscapes“Favorable townscape”, identified by each region
Measures for townscape conservation have been implemented under joint enforcement of the Law for the Protection of Cultural Properties, the City Planning Act and the Building Standard Law.
From the 1960s to the 1970s, a movement to conserve townscapes occurred across the country, which led tothe current activities of re-evaluating and maintaining old and modern architecture that form townscapes uniqueto each region, although they are not as valuable as national cultural resources.
Various measures are now being developed to create beautiful townscapes for the future, which will remain as
one of the scenes of the history, while respecting the characteristics of each region.
II

095

Renovation/
Conversion

3

Legal Framework—

098
Restriction of Floor
Area Ratio

096

Facilities/style/structure/regulations that demonstrates governing power
Japan constructed a variety of buildings in colonies that Japan governed from the end of the 19th century
through the early 20th century.
The priorities were facilities required for colonial governance, which were government buildings and hospitals.
Brick construction was used for the structures of these buildings for the purpose of making the cities safe fromfires, while maintaining their aesthetic value.
Initially, those buildings were modeled after the architecture of powerful Western countries, such as Queen Annestyle- and Neo-Baroque style buildings. However, in 1931, when the Manchurian incident occurred, Japan began to adopt Asian-style architectural designs.

A means to regulate density in urban areas
As the total floor area of buildings grows, the active population of the area increases, which imposes a bigger
load on the infrastructure, such as roads and water/sewage systems.
The restriction of the floor-area ratio is a measure to balance the total building floor area of a city and the capacity of the city’s infrastructure by restricting the ratio of the total floor area of each building to the building lot.
In the old days, the density of a city was controlled indirectly by restrictions on the maximum building height
and the building coverage ratio. To comply with the boom of higher and larger-scale building construction
during the period of high economic growth, the density control method was changed in favor of the restrictionof floor-area ratio.

097
photo: NISHIZAWA Yasuhiko

089–098

the Edo era: 1603–1868 / the Meiji era: 1868–1912 / the Taisho era: 1912–1926 /the Showa era: 1926–1989 / the Heisei era: 1989–2019 / the Reiwa era: 2019–31

100 SELECTED BUILDING TECHNOLOGIES

098100Colonial Architecture

From the late 1990s through the first decade of the 2000s, there was a fundamental shift in the Japanese building industry; from the period when newly built construction was dominant, to the era of repair/renovation/usage
conversion of existing buildings.
Housing starts, which once reached almost two million units a year, steadily declined and have been fewer than
one million units a year since 2009. Currently, the housing stock surplus is a serious problem that reflects theshrinking population. In order to utilize the value of the housing stock, renovation/conversion is inevitable to keepthem as social assets. This idea is now a major trend in the building industry and in the cultural sector as well.

089

097

Towards new value of architecture created by growing imagination for building usage

IV

096

Beginning in the Meiji era, Japan adopted Western style housing with both the exterior look and designs of theliving space. After the World War II, there was no room to consider the regional climate or culture when constructing houses, due to a severe shortage of building materials and labor for the huge housing demand. Under
the sharp economic growth afterwards, a nationwide housing provision plan was carried out, facilitated by thedevelopment of new building materials/components and production technologies, as well as the trends towards
the nuclear family and urbanization. However, houses had traditionally been built with floor plans, forms andmaterials that reflected each regional characteristic. Those houses actually created the townscape and scenic
beauty that is unique to the region, which eventually generated a specific local attractiveness. Based on suchview, the “HOPE (Housing with Proper Environment) Plan” started in 1983 as a government program for promoting housing that is suitable for each regional climate and culture.

III

Regional Houses

Measures to provide houses suited to each local climate and culture

100 KEY TERMSV

POLICY / REGIONAL PLANNING

3—Legal Framework

I

099

From barrier-free for the disabled, to a subject common to all human beings

Universal Design

The barrier-free design, which was established during the 1980s in Japan, was based on the premise of excluding all existing barriers in the physical environment, people’s consciousness, information and social systems.
Beginning in the 21st century, on the other hand, a universal design spread, which aims to allow access to as
many people as possible to spaces, the environment, products, and the provision of services.
A point common to both barrier-free and universal design is their objectives, which is to establish cities and asociety where diversity is accepted and no discrimination exists, in order to eliminate existing barriers and toprevent the creation of new barriers in the future.
II

100

Changed to legislation that enhances design flexibility and introduction of new technologies

IV

099–100

III

Introduction of
Performance-Based
Building Regulations/Standards

Specification-based regulations/standards require buildings to conform to specifications of size, shape, usedmaterials, etc. that are stipulated in the regulations, whereas performance-based regulations/standards simply
require buildings to have a certain level of performance. Under performance-based regulations/standards, it ispossible to use various materials, equipment and structural methods if they satisfy the required performance,
which heighten the flexibility of building designs, and also streamline the process of introducing new technologies and products from overseas. The Building Standard Law was initially established as specification-based
regulations/standards. For products/technologies not specified in the Law, it was required to obtain approvals
under Article 38 of the Law. In 2000, the Building Standard Law was drastically revised in order to incorporate
performance-based regulations/standards into it.

100th Anniversary of Enactment of City Planning Act and Building Standard Law
VArchitecture that Supported Modernization of Japan– 100 selected building technologies

099100

Table of Contents- Preface- Contents- Chronology- Overview: Modern and Contemporary Japan Supported by Architecture- 100 Selected Building Technologies
		

Chapter 1 Housing		

Chapter 2 Buildings		

Chapter 3 Structural Methods

		

Chapter 4 Building Production/Facilities

		

Chapter 5 Policy/Regional Planning- Roundtable Talk:- Index- Writers Profiles

Published in:Edited by:		
Published by:		Contact:		June 2019
Committee for:“Architecture that Supported Modernization of Japan”
The Building Center of JapanThe Japan Architectural Education and Information Center
The Building Center of Japan
1-9, Kanda-Nishikicho, Chiyoda-ku, Tokyo, 101-8986, JAPAN32

100 SELECTED BUILDING TECHNOLOGIES

Phone:
URL:
Price:+81-3-5283-0461
https://www.bcj.or.jp/
Japanese yen 4,500-

ISBN 978-4-88910-177-5(This number is for the book in Japanese language)©2019, The Building Center of Japan

100 KEY TERMS

Writers

Writers of “Key Terms of 100 Selected Building Technologies”
001 Residential Suburbs

OBASE Reiji

051 Tubular Structures

TAKEUCHI Toru

002 Dojun-kai Apartments

OTSUKI Toshio

052 Shell/Spatial Structures

SAITOH Masao

003 Coal Miners’ Housing

KIKUCHI Shigetomo

053 Membrane Structures

KAWAGUCHI Ken’ ichi

054 Retractable-Roof Domes

KAWAGUCHI Ken’ ichi

TAKADA Mitsuo

055 Seismic Technology for Wooden Housing

SAKAMOTO Isao

005 Danchi

UEDA Makoto

056 Structural Analysis of Traditional Wooden Buildings

006 New Towns

NARUMI Kunihiro

		

KAWAI Naohito

007 Condominiums

KOBAYASHI Hideki

057 Two-by-Four Buildings

ABE Ichiroh

008 Multi-Unit Housing Operated by Private Sector MORIMOTO Nobuaki

058 Fire Preventive Construction

HASEMI Yuji

009 Cooperative House (Building co-operatives)

NAKABAYASHI Yoshiyuki

059 Fire-Resistive Wooden Buildings

YASUI Noboru

010 Collective Housing

HINOKIDANI Mieko

060 Large-Scale Timber Buildings

KOSHIHARA Mikio

011 Skyscraper Condominiums

ANDO Masao

061 Cast-in-Place Concrete

NOGUCHI Takafumi

004 Publicly-Operated Housing and Japan Housing Corporation (JHC)
Housing

012 Emergency Temporary Housing and Restoration Housing

062 Alternative Materials e.g. Bamboo-Reinforced Concrete		

WATANABE Shiro

		

HAYAMI Kiyotaka

013 Minimal Houses

TSUKAMOTO Yoshiharu

063 Exposed Concrete Finish

FUJIMORI Terunobu

014 GHLC Specification

MIZUTANI Tatsuro

064 PCa Concrete/PC

OKAMOTO Shin

015 Cold-Region Housing

TANIGUCHI Naohiro

065 Foundation/Ground Improvement

FUJII Mamoru

016 Housing for the Elderly

SONODA Mariko

066 Reuse/Recycling of Building Materials

TSUNODA Makoto

017 Housing Performance Indication System

SUMIKURA Hideaki

067 Measures to Ensure Safety of Workers

KANISAWA Hirotake

018 Prefabricated Housing

MATSUMURA Shuichi

068 CAD/BIM

KANO Naruo

019 Pilot Projects

YOSHIDA Takuro

069 Exterior Tiles

OMI Yasuo

020 Skelton-Infill House (Base building and fit-out for housing)

070 Aluminum Sashes

MANABE Tsunehiro

		

MINAMI Kazunobu

071 Curtain Walls

SEIKE Tsuyoshi

021 Precutting

GONDO Tomoyuki

072 Glass Buildings

INOUE Tomo

022 School Buildings

NAGASAWA Satoru

073 ALCKITSUTAKA Yoshinori

023 Public Cultural Facilities

SATOH Shinya

074 Plywood/New Building Materials

ANDO Naoto

024 Government Buildings

ISHIDA Junichiro

075 Waterproofing for Roofs

TANAKA Kyoji

025 Modern Architecture

YAMANA Yoshiyuki

076 Gas Water Heaters

KURABUCHI Takashi

026 Okinawan Architecture

MATSUBA Kazukiyo

077 Ventilation Fan

KOMINE Hiromi

027 Religious Buildings and Memorials

IGARASHI Taro

078 Stainless Steel Sinks

WADA Nahoko

028 Tower

YOSHIMI Shunya

079 Prefabricated Bathroom Unit

MANABE Tsunehiro

029 The Tokyo Olympics

TOYOKAWA Saikaku

080 Western-Style Toilet

KAMATA Motoyasu

030 Japan World Exposition, Osaka 1970

HASHIZUME Shinya

081 Johkasou Systems (Domestic wastewater treatment facilities)

031 Station Buildings with Shoppping Centers

FUJIMURA Ryuji		

032 Arcade

TSUJIHARA Makihiko

082 Electrical Equipment/Lighting Appliances

GOTO Masahiro

033 Underground Mall

HATSUDA Kosei

083 Opening Protective Assembly

HAGIWARA Ichiro

IWAHORI Keisuke

034 Pedestrian Decks

FUJIMURA Ryuji

084 Elevators

FUJITA Satoshi

035 Public Open Spaces

ASAMI Yasushi

085 District Heating and Cooling System

IBAMOTO Tadahiko

036 Urban Redevelopment

ASAMI Yasushi

086 Intelligent Buildings

OKISHIO Soichiro

037 Urban Waterfront Development

YOKOUCHI Norihisa

087 Insulation & Energy Efficiency

SAKAMOTO Yuzo

038 Shopping Mall

MATSUBA Kazukiyo

088 Sustainable Buildings

KODAMA Yuichiro

039 Downtown

ISHIGURE Masakazu

089 Fukko Shogakko (Restoration primary schools) KANAYAMA Mahito

040 Convention Center

ISO Tatsuo

090 Fire Preventive Building Zones

HAYAMI Kiyotaka

041 Theme Parks

INOUE Shouichi

091 Slum Clearance

ISHIGURE Masakazu

042 Concrete Block Structures

KUMAGAI Ryohei

092 Measures for Densely Populated Urban Areas YAMAMOTO Toshiya

043 Steel Structures

YAMADA Satoshi

093 Preservation/Conservation of Historic Architecture

044 Steel Encased Reinforced Concrete Structures KUMAGAI Ryohei

		GOTO Osamu

045 Reinforced Concrete Structures

FUJIOKA Hiroyasu

094 Conservation of Townscapes

EBARA Sumiko

046 Seismic Design Provisions

SHIOHARA Hitoshi

095 Regional Houses

MIISHO Kiyonori

047 Seismic Isolation Systems

NISHIKAWA Takao

096 Renovation/Conversion

SYNBORI Manabu

048 Response Control

WADA Akira

097 Colonial Architecture

NISHIZAWA Yasuhiko

049 Seismic Retrofit

NAKANO Yoshiaki

098 Restriction of Floor Area Ratio

OSAWA Akihiko

050 Skyscrapers

GONDO Tomoyuki

099 Universal Design

TAKAHASHI Gihei

100 Introduction of Performance-Based Building Regulations/Standards
GOJO Wataru

C3

100 SELECTED BUILDING TECHNOLOGIESArchitecture
That Supported
Modernization of
Japan

002

003

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007

022

024

025

026

034

036

037

040

042

044

045

049

061

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064

066

090

092

093

094

100 selectedbuilding technologies
An English Summary

MORI Masayo						International Consultant and Translator
Area of expertise: Buildings and wood products

ISO Tatsuo		

Editor

ARATAME Shinobu

Book Design