Cultural Heritage Online:
Information Access across Heterogeneous Cultural Heritage in Japan
Noriko Kando, Jun Adachi
National Institute of Informatics, Japan{kando|adachi}@nii.ac.jp

Abstract
This paper discusses the metadata schema for Japan’s
Cultural Heritage Online project. The purpose of the
project is to set up a portal site providing seamless
access to heterogeneous digitized cultural heritage
objects across a wide variety of digital collections
prepared by archives, museums, national, regional
and local cultural heritage centres, and other relatedorganizations in Japan for both Japanese andinternational users. It covers both tangible objects
such as paintings, buildings and other artefacts, andintangible objects including theatre performances anddance, as well as art that creates artefacts. The key
issues in system design are mechanisms forcontinuous
search-and-navigation
througha
combination of content- and structure-based retrieval.
Metadata and community-oriented ontology are themain components on the structure-based side,
together with an associative search engine on thecontent-based side. In conclusion, problems andfuture directions in design of structure and searchfunctionality are discussed.
Keywords:
CulturalHeterogeneous Metadata

Heritage,

Metadata,

1 Introduction
Cultural Heritage Online is a portal site to provide
access to various digitized cultural heritage objects inthe collections of museums, archives and relatedorganizations in Japan. It was proposed in an interim
report [1] of the Committee on Cultural Heritage
Digitization Strategy, under Japan’s Agency of
Culture. The report also emphasized the necessity toencourage the digitization of cultural heritage objects
in the various organizations. It strongly
recommended that Cultural Heritage Online should
cover 1000 sites of museums, archives and otherrelated organizations by the end of fiscal year 2006.
In response to the report, the committee’sTechnical Subcommittee has discussed detailed
problems to establish a roadmap of the project byApril 2004, and a pilot system was implemented toencourage and mediate discussion and dialogue
among the various communities related to thecreation and use of cultural heritage objects. The
roadmap will pay special attention to metadata

schemes and rights management. The discussion anddialogue include, but are not limited to, theimplications of digitization and building a portal site,
the site’s search functionalities and usability,
information architectures including the metadata
schema, types and formats of the digitized objects,
and the current status of the information managementof the cultural heritage objects in each site.
1.1 Digitization of Cultural Heritage
Unlike library materials, which are basicallypublished objects, and other tokens of the same typethat are available elsewhere, cultural heritage objects
are basically unique and their usage and accessibility
are quite limited in their original physical form. The
implications of the digitisation of cultural heritage
objects are tremendous and include the following
aspects:
1.
2.
3.
4.
5.

Enhanced usage and accessibility;
Multiple versions for different user groups or
purposes;
Independent from the collection or context;
Virtual combination, comparison, or restoration;
Preservation.

The digitized objects are accessible regardless ofgeographic location. Especially this enlarges theopportunities for educational purpose use and benefit
for enhance the mutual understanding between
different cultures in the world. Multiple versions ofimages are often available for different purposes, forexample, ultra high resolution images for publication,broadcasting, virtual exhibition or other content
industries; thumbnails to quickly identify therelevance of the objects, typically in search systems;
and mid-level resolution images for classroom use.
By digitization, any object can easily be moved to adifferent location or context from the originalcollection, a new collection or comparison with otherobjects can be virtually constructed, and objects caneven be restored virtually.
1.2 Digitization and Metadata
The importance of the metadata is increased when
cultural heritage objects are digitized. For example,
the metadata can improve the search effectivenessand usability of the search system by providing

multiple access points and preserving the semantics
and context of the objects. The metadata is also
critical in linking the multiple versions of the same
object and objects from the same collections. It can
provide detailed description frameworks appropriate
for each community as well as more generalframeworks for resource discovery across different
communities. Information for preservation and rights
management can be recorded as metadata.
The scope of Cultural Heritage Online is
introduced in the next section. Section 3 describes thepilot system and its functionality, and Section 4
discusses the difficulties and problems of metadata
for cultural heritage objects. Finally, some thoughts
on future directions are presented.

2 Scopewithout defining their information needs as specificqueries, and enjoy the interaction.
Currently the pilot system contains about 5,000
records, provided by 35 museums, archives and otherrelated organizations for experimental purposes. We
are grateful for their cooperation and quick responses
to our requests.
The current version of the pilot system was
implemented by Marukawa and Takano by modifying
their experimental system called Mozume [2].
Figure 1 shows an overview of the searchmechanism of the pilot system. The basic designconcept is “search and navigation”. It combines
content-based
moderninformation
retrievaltechnology using statistical features of the objects
with metadata-based navigation.

The scope of the cultural heritage objects included
is quite wide and heterogeneous. As shown in Figure
2, we plan to include such types of cultural heritage
object as tangible objects such as paintings,
sculptures, crafts, archaeological objects, historicsites, architecture and buildings, scenery, naturalmonuments and protection intangible objects like
performance and dance, and the arts of creating theartefacts and crafts. Each community related to a
genre has its own culture and ontology to describe theobjects. To provide access across these varieties ofcommunities is one of the challenges of Cultural
Heritage Online.
The categorization of the object types itself is amatter for discussion. For example, should an object
be categorized by the materials and techniques usedin its creation (e.g., porcelain), or by usage (e.g., tea
wares)? Such questions are deeply related to the
ontology of each community and school.
In the database, the formats of the digitized objects
are basically metadata and thumbnails of the digitizedobjects in each digital archive collection, with links
to these objects for further information and moredetailed images. The pilot system also accepts
multiple sizes and resolutions of images, and somevideos.

3 Pilot System
A pilot system was implemented as a tool or
medium to encourage discussion and dialogue among
the various communities related to the creation anduse of cultural heritage objects.
The primary target users are non-specialist ordinary
citizens without any technical or professional
background in cultural heritage. School students andteachers are one group likely to use the systemheavily. The users can initiate the search process

Retrieve
Related books

Metadata
Metadata
Name:
Metadata
Name:
Creator:Name:
Creator:Desc:
Creator:
Desc:
URL:
Desc:
URL:
URL:

keywords

keywords

Metadata
navigation
DATE
GENRE
PLACE

Objects on
Museum’s
site

Entry
page

Query terms
keywords

Search Results,
Displayed in Matrix form

Figure 1. Search mechanism of the pilot system
On the pilot system’s top page, shown in Figure 3, auser can enter query terms in a window or selectsome values from the pictorial pull-down menus foreach facet of metadata, Time, Type or Place. The
retrieved records are then displayed in the matrix
format so that the user can see as many images as
possible at a glance.1 Figure 4 shows an example of
the retrieval results when the user selected“porcelain” from the genre facet metadata pictorial
menu shown in Figure 2.
Among the displayed images, if the user isinterested in a round dish with red or pink flowers,
then the two are selected from the displayed results,
and searched again. As shown in Figure 5, objects
similar to the selected items are retrieved anddisplayed. In this way, users can continue the searchand navigation as far as they wish until they aresatisfied. In such a system, the total experience and1

The matrix format display is commonly used byonline shopping sites.

Architecture
Religious
CastlesHousesModernPre-modern

Historic Villages
Samurai towns
Post towns
Ports
Farm/Mt Villages
OthersPictures/Paintings
PrintsJapanese
WoodenOil paintings
Etchings
Water paintings
LithographAsia (Non-Japanese)
Silkscreen
OthersOthersSculptures
Wooden
Metal
Stone
Bone
Others

Craft/Artefacts
Metal
Lacquer
Dyeing/Textile
Porcelain
Glass
OthersArchaeology
Stoneware
Earthenware
Metalware
Bone/teeth
OthersHistory
Documents/Books
Maps
OthersOther Arts
Photographs
DesignHandwriting
OthersFolk Art
Tangible
Intangible

Traditional
Performing Arts
Noh
Bunraku puppets
KazukiMusic
OthersRestoration
Architecture
Paintings/Sculptures
Historic sites
Traditional
Artefacts

Historic Sites
Scenic Beauty
Ancient tombs
Gardens
Temples/Shrines
Ravines/Rivers
Castles
CastlesVillages
OthersNatural Monuments/Protection
Protected animals
Protected plants
Geological features/Minerals
Protected areas

Figure 2. Genres of Cultural Heritage Objects

Time

Type

Place

Figure 3. Top Page of the Pilot System

Use these selectedrecords as a query
Figure 4. Two Round Dishes with Red Flowers are Selected from the Search Results of “Porcelain/China”

Figure 5. Search Results of the Figure 3.

everything that the user learns through interaction
with the system are the results of the retrieval.
For the content-based retrieval, Mozume and thepilot system use a search engine called GETA [3]. It
is a content-based text retrieval system, and therefore
the pilot system currently does not utilize any
content-based information from images, but uses
textual description in the metadata. In GETA,
documents are usable as queries, and the system
retrieves related documents from the user-selected
documents and provides a list of highly associatedkeywords that can be used to enhance further
retrieval. Using this associative search function, users
can progressively search for similar objects.
This is also similar to the concept of the “Ostensive
Search”, search without query, proposed by Ian
Campbell [4], and thought to be effective and usefulfor users who do not have clear search requests prior
to the search.
From the textual description of the retrieved
metadata, information about related books can also be
retrieved using NII’s WebCAT Plus [5], an Online
Union Catalog Database freely available on the web,which also in corporates associative search functions
using GETA.

3.1 Simple Metadata
The current version of the pilot system barely
utilizes metadata, because it was implemented before
the detailed discussion of the metadata schema. The
metadata submitted from 35 museums and otherrelated organizations contained such fields as title,
title.yomi (pronunciation of title), description,
number, size, designation (for instance, as nationaltreasure), materials, structure and technique, creator,
publisher, contributor, date.created, date.published,date.collected, subject.local-classification, URL,
object id, place.produced, place.collected, place.used,
place.found, and place.archeological-site-name. The
pilot system uses only the very simple facets of date,genre and place in the search interface for navigation
using pictorial menus. Institutions were asked toprovide descriptions at least 300 characters long(about 150 words in English) to allow effective
associative search.
Figures 5 and 6 show the pictorial menus for the
facets of DATE and PLACE. An interesting point isthat DATE and PLACE are integrated with eachother. The era is defined by each country or area, and
PLACE name can vary according to the time period.

JapanKoreanPeninsula
Showa

China

TaishoMeiji
Edo
AduchiMomoyama

Muromachi
Figure 5. Example of Pictorial Menu on DATE/ERA (for Japan)

Figure 6. Example of Pictorial Menu on PLACE

3.2 Iterative Improvement and Redesign

consideration of the workforce in each member
museum to creating the metadata, we are discussing
metadata requirements carefully.

The technical subcommittee has discussed themetadata schema, and according to the roadmap wehave set, specialized working groups consisting of
curators and information architects from each
community will decide the metadata schema to be
used in Cultural Heritage Online. Ontology
development is also included in the task of thisworking group.

The primary aim of the metadata for Cultural
Heritage Online is to provide access acrossheterogeneous objects, i.e., metadata for resource
discovery and interoperability. Therefore it willbasically be rather simple, but we hope that the
mapping and conversion from each community’s
metadata and ontology can be done comfortably for
all communities.

A combination of content-based retrieval andstructure-based search using metadata features
theoretically has a good possibility of working well,as the two complement each other and are especiallyeffective for a large-scale database with a rather small
controlled vocabulary or less-controlled metadata
descriptions. Algorithms to combine the two
approaches more effectively will also be investigated.

4.2 Discussion of Cultural Heritage Metadata
Below are some examples that we have considered
so far. The point here is that the design of themetadata schema is deeply related to the design ofsearch functionalities, especially the user interface tomultifaceted metadata for navigation.

The search functionality and metadata schema will
be gradually improved through an iterative process ofusability tests or evaluation by users and creators, andredesigning.
The next section discusses some of the issues
related to metadata raised by the discussions we have
had so far. These may depict some of the problems
and challenges regarding metadata of cultural
heritage objects.

4 Discussion of Cultural Heritage
Metadata and Further Functionalities
To utilize all the advantages of cultural object
digitization mentioned above, effective and easy-touse search functionality and appropriate metadata
schemas are required.
4.1 Standards for Cultural Heritage Metadata
For the cultural heritage objects and related areas,
there are several well-used standards for metadata. As
a basis for discussion, we have surveyed thesestandards and their inter-relationships. They include:
SPECTRUM, by the Museum Documentation
Association (MDA); CIDOC CRM, by theInternational Council of Museums Documentation
Committee; the Simple Dublin Core and CIMI’s
Guide to the Best Practice Dublin Core; Categories
for the Description of Works of Art (CDWA);
Encoded Archival Description (EAD); and otherwork by some major museums and archives.
Based on the survey, we are reviewing the objects
currently included and to be included in Cultural
Heritage Online. Because of its wide variety,including intangible objects and scenery, and withTitlesIn some types of cultural objects, the title is notclearly defined, or more precisely, only a rather small
number of objects types have “titles”, which they
have often been given in recent times. For example,
the titles of archaeological objects are usually object
names. The titles may be also changed for eachexhibition. Naming is sometimes a right of theowner; owners of objects may name them according
to their preferences.
Owners and History
Related to the above observation, the owners of theobjects and the histories of the owners are often
critical attributes to differentiate one object fromothers. Relations such as “who created this forwhom?” and “who gave this to whom?” are useful
information to differentiate objects as well as toenvisage the value of the objects.
Value
Cultural heritage objects are generally valuable,
and users often wish to search and enjoy “valuableobjects” without a clear definition of how valuable
they are. However, as a metadata record to describe
the object, it is not appropriate to say, for instance, “itis valuable”. Instead, descriptions of attributes thatindicate the value of the object are often useful forthis purpose. Awards, designation as National
Treasures, signatures of creators, or the signature of
the eminent people who owned it before or to whom
it was dedicated are examples of attributes indicating
value.
Relationships
Cultural objects do not usually exist alone, and areoften part of a collection or have relationships toother objects. This provides the context of the object,
and without these contexts, the value and indicationof the objects cannot be assessed correctly.

Collections vs. Single Objects
The choice of collection-based description or itembased description is often an issue.
Community-based Metadata or Ontology
Each community has its own metadata schema andontology. In particular, intangible objects including
Japanese traditional theatre performances such as
Kabuki have very strong traditions. More detailed
analysis of this domain is necessary. Scenery is also acharacteristic object included with cultural heritage
objects, but is often closely related to architecture andreligious objects.
Scaling and Fuzzy Matching
Numeric descriptions of size or year are often too
rigid and strict. In the historical record, there issubstantial confusion about the time periods ofdynasties. It will thus be useful and more practical tospecify these numeric values in more tolerant orvague ways.
Place Names and GIS
Place names and the places indicated by a given
name are not stable over time.
Exhaustivity vs. Selectivity
What objects should be included in Cultural
Heritage Online? Should we try to include the wholecollection of every museum, or should each museum
select the “good” or “valuable” objects that they wish
to show many people all over the world?
Isolated Objects vs. Systematic Knowledge
The current pilot system has search functionality
only over isolated objects. We can enjoy finding
unexpected relationships or similarities between
objects through associative search. Often, however,
we would like to gain more-systematic knowledge
about objects and their relationships, and understandthe value and meanings of an object by relating theobject to systematic knowledge. How to construct thedata for systematic knowledge and how to implement
it on the system is an interesting challenge.
Currently, the pilot system has a link to NII’s
WebCAT Plus, a web-based union catalogue searchservice of Japanese university and research libraries,
which is also powered by the same search engine
with the pilot system. The users can retrieve therelated books using the retrieved cultural heritage
object as a query. We also solicit museum curators orother specialists to contribute “virtual exhibitions” toconnect and relate isolated objects in systematic ways.
This is an example of an attempt to overcome theproblem of simple aggregation of single object andproviding some systematic view among them byhuman effort.

RightsWe tried to restrict the scope of the system todescription and discovery of the resources. Rights
management is not the primary target of the project
and will be done elsewhere. However, we must still
consider rights management to some extent.
Paradigms and Viewpoints
Description of cultural heritage objects may differ
in the principles, paradigms, viewpoints andinterpretation of each creator of the metadata andusers. When aggregating metadata from various sites,
there can be conflicts between descriptions andvalues.
Other Issues to be InvestigatedFurther possible research and investigation for
better information access for cultural heritage objects
includes: cross-lingual information access, especiallyfor Asian communities; content-based retrieval using
image content information combined with textual
information in metadata and metadata; and automatic
metadata enrichment using natural language
processing techniques.

6 SummaryThis paper offers a brief overview of the Cultural
Heritage Online project and discusses the issues
relating to the metadata for cultural heritage. The
project itself is under way, or more precisely will
start from this coming April. From April we areorganizing a working group to discuss in detail about
metadata scheme in each of the communities related
to cultural heritage, then finalize the metadata scheme
used for the Cultural Heritage Online, as well asorganizing various attempts and effort to digitizing
the cultural heritage and enhancing the access to them.
Any comments, leads or suggestions are always morethan welcome.

References[1] “Bunka Isan Johoka Suishin Senryaku Chukan Matome(Interim Report. Strategy of Cultural Heritage Objects
Digitization, translated by the authors)”. Bunka Isan Johoka
Suishin Senryaku Kaigi, 26 August 2003, 21pp. (inJapanese)[2] Marukawa, Y., Takano, A., Takamizawa, A., “Mozume:
An Associative Information System for Cultural Heritage”,
in: Proceedings of the Second NII International Symposium,
Nara Symposium for Digital Silk Roads, December 2003,
Nara, Japan[3] GETA. The Source code is available at:
http://geta.ex.nii.ac.jp/e/index.html[4] Campbell, I., Reisbergen, K. “Ostensive Retrieval of
Image Documents”, in: Proceedings of the Second CoLIS,
October 1996, Copenhagen, Denmark[5] WebCAT Plus: http://geta.ex.nii.ac.jp/e/index.html