Chapter 19
The Paradigm Shift in Urban Regeneration
Field of expertise: Planning technology for urban revitalization

Tsukasa Iwata
Summary
Most of the areas affected by the Great East Japan Earthquake are mainly low-rise wooden
houses, and most of the reconstruction houses are also wooden houses, except for disaster public
housing in urban areas. Utilizing the local living culture and existing stock in the area for housing
reconstruction in these areas will be a new urban renewal method for regional revitalization and asuper-aging society.
Keywords: wooden emergency temporary housing, local reconstruction housing, group relocation,local revitalization, local housing builder

Introduction
In the event of a disaster, it is necessary to revitalize the lives of not only the city but also
the entire area such as the surrounding rural areas. In addition, the rapid changes in the social
structure after World War II have significantly changed the way of life in modern areas that havebeen cultivated over many years, and the appearance of the regenerated areas will change
significantly from before.

1: Problems revealed by the Great East Japan Earthquake
What happened?
Most of the building damage caused by the Great East Japan Earthquake was caused by
the tsunami. Most cities in Japan are occupied by wooden houses (Figure 19-1), so many buildings
were washed away. Therefore, it was necessary to reconstruct these areas by providing newresidential areas such as relocating residential areas from areas that are in danger of tsunamis andland reconstruction, accompanied by raising the ground level to prevent tsunamis, and as a result,it took a long time for reconstruction. During that time, the supply of comfortable temporary housing
became an important issue.
In the Great Japan Earthquake, more than 50,000 temporary housing units were built. Thistime, a local construction company also constructed wooden temporary housing. Especially inFukushima Prefecture, the total supply of 17,143 temporary housing units, 6,639 (38.7% of thetotal supply) was supplied by local contractors (Photo 19-1). It was reported that this wooden
emergency temporary housing is much more comfortable than the prefabricated temporary1housing because it was designed and constructed by a local contractor who is familiar with thelocal climate and housing culture.
For reconstruction housing, local production groups were formed and constructed by local
builders, design offices, foresters, timber manufacturers, building material manufacturers, etc. whoare familiar with the local climate and housing culture. For these groups, the Ministry of Land,
Infrastructure, Transport and Tourism supported the construction of these houses by utilizing theRegional Housing Branding Project subsidy system. These are also efforts that consider regionalrevitalization as well as reconstruction.

Figure 19-1. The number of Japanese housing units by structure/building (left), number offloors/building (right). There are about 53,655,600 houses in Japan, 55% of which have a woodframe, and half of them are wood-frame detached houses. Sixty-five percent are detached houses
and apartments with 2 floors or less, and only about 7% of high-rise houses with 11 floors or more.
(From the 2018 Housing and Land Statistics Survey)

Photo 19-1. Wood-frame temporary housing by the Miharu Reconstruction Housing Association, agroup of local construction companies in Miharu, Fukushima Prefecture. It was built on the groundsof the park using the current greenery. These are comfortable temporary houses with the scent ofwood, which use a lot of natural wood for both interior and exterior, and at the same time consider
high heat insulation and high airtightness. Residents also highly evaluated these temporaryhouses. (Photo by Iwata)
The reality of the damage
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The number of buildings that were seriously damaged by the Great East Japan Earthquake
amounted to about 400,000, and it was thought that 100,000 homes would need to be rebuilt. Of
these, about 30,000 were built as disaster public housing. Approximately 18,000 plots wereprepared as residential land through the land readjustment project, disaster prevention group
relocation promotion project, and the fishery settlement disaster prevention function enhancement
project. It took 7-8 years for all of the construction.

2: Paradigms Destroyed by the Earthquake
Conventional wisdom and necessary responses
Japan is facing a declining population and a super-aging society with a declining birthrate.
For this purpose, urban renewal methods need to prevent urban sprawl to the suburbs, bring thepopulation back to the old urban area where infrastructure already exists, and create a walkabletown that responds to the aging society. In other words, it is necessary to make it a compact city.
However, the Great East Japan Earthquake created a banned area due to the tsunami, and manygroup relocations resulted in many suburban housing estates scattered in the mountains. In
addition, more residential areas were supplied to the suburbs through land readjustment projects.
On the other hand, there are many traditional towns and villages in the disaster area. The
reconstruction of these commercial, agricultural and fishing facilities was separate from thereconstruction of housing. This is because housing cannot be built in the areas affected by thetsunami. This situation is similar to the relationship with suburban housing estates and largecommercial facilities. In addition, the lifestyle will be commuting, shopping, and entertainment
based on the premise of a car-based society.
As a result, we went against the urban renewal method required by Japan's current
population decline, declining birthrate and super-aging society, and used the method of expanding
to the suburbs of the 20th century. As a result, Japan's compact system of towns and villages
close to work and residence that has existed since ancient times has been abandoned, and at thesame time, the landscape of Japan's wood-framed buildings along streets and villages has beenlost.

3: A New Approach
The Regional Housing Plan was started in 1983 as a national subsidy project to implementa housing policy unique to the region based on the living culture of the region. This was done fromthe reflection on the overconcentration in big cities and the standardization of cityscapes andhouses nationwide. As a result, it has become common to consider the regional characteristics ofcurrent housing and community development.
Japan belongs to the monsoon climate zone as a whole. It is hot and humid mainly in summer, andlow temperature and low humidity in winter. In addition, there are regions with a wide variety ofclimate characteristics, from Hokkaido, which has a cold climate, to Okinawa, which has asubtropical climate. Each region has cultivated a unique culture made of wood-framed buildings. Itis the traditional construction companies in each region of Japan that have supported these fromancient times.
The economic spillover effect on housing construction is great. In addition to direct
construction costs, there are various ripple effects such as incidental works such as electrical work
and water and sewage works, moving costs, purchase of durable consumer goods, and interest
payments on mortgages. It can be derived from the input-output table that the final demand3amount considering the secondary effect is more than twice the direct investment amount, andabout 20% of it is tax revenue. For example, if the construction cost per building is 25 million yen(approximately 217,000 USD), the final price including the secondary effect will be 51.7 million yen(approximately 450,000 USD), and the tax revenue will be 4.8 million yen (approximately 42,000USD). Most of the houses in the area are wood-frame detached houses, and if a local builder canbuild it, it will lead to great revitalization of the area. Therefore, if a local builder who is familiar withthe local climate and culture actively participates in these series of housing reconstructions, it will
be possible to simultaneously realize regional housing/town development and regional
revitalization as well as reconstruction.

4: Achievements and the Future
In the Great East Japan Earthquake, regional production groups cooperated to open thedoor to the supply of regional reconstruction housing, rooted in the local culture at the time of thedisaster. Regional reconstruction methods that utilize the power of these regions were also
realized in Totsukawa Village in the 2011 Kii Peninsula flood, the 2016 Kumamoto earthquake, andthe 2017 northern Kyushu flood. In Totsukawa Village, we have realized the construction of awooden emergency temporary housing and a regional reconstruction housing using local timber.
Instead of constructing housing that needs to be relocated in a new land like the Great East Japan
Earthquake, regional disaster public housing was constructed by utilizing the vacant lot of theexisting village. In other words, it shows that the relocation project and the disaster public housing
construction project can be constructed of wood-frame structures and the vacant lots in the existing
urban areas can be used to revitalize the area and realize a compact city.

Conclusion - from the author
Trees are living things. Therefore, if used improperly, it will rot and die. Japan's woodtechnology for over a thousand years has overcome it and built up local housing cultures. Due to
new technological innovations such as CLT, wooden skyscrapers are beginning to be realized.
Many of Japan's buildings are made of wood and this will continue to be the mainstream. When
local communities realize this, a resilient and truly sustainable housing and town space, unique toJapan, will be created. I want to expect that.

References
Architectural Institute of Japan. (2016). Final Report of Special Investigation Committee onConstruction of Effective Reconstruction Assistance in the Great East Japan Earthquake. (InJapanese)
Iwata, T. (2016). Kumamoto Earthquake Damage Survey Report-Housing / Community
Development-. Tohoku University, International Research Institute of Disaster Science.
https://irides.tohoku.ac.jp/media/files/_u/topic/file/20160929_Kumamoto_EQ_report_Iwata_web.pdf(In Japanese)
Iwata, T., Miisho, T. (2012). How to supply temporary housing by local carpenters who support
local housing construction. Architectural Institute of Japan Technical Report, 20(45), 503-508.
https://doi.org/10.3130/aijt.18.1093
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