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Mission and Roles


"The NDL is hereby established as a result of the firm conviction that truth makes us free and with the object of contributing to international peace and the democratization of Japan as promised in our Constitution."

(From the Preamble of the National Diet Library Law)

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Support to the Diet

(1) The NDL supports the Diet and assists the activities of Diet members, using its professional expertise in research and accumulated information resources.

  • Research on request: The NDL carries out legislative research on a wide variety of national issues related to politics, economy, society, or science and technology in response to requests from Diet members.
  • Anticipatory research: The NDL carries out research and publishes research papers in advance on subject matter it anticipates will prove germane to national politics.

(2) The NDL database of the minutes of the Diet and laws in the Japanese language keep the general public informed of Diet activities via the internet.

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Acquisition and preservation of materials and information

(1) Material Acquisition

Domestic Publications - Legal Deposit System

The National Diet Library Law requires that all publications published in Japan, including microfilms, CDs, DVDs, maps, and more, must be deposited with the NDL. Through the Legal Deposit System, the NDL collects many domestic publications as the only legal deposit library in Japan. It also holds domestic publications which were published before the legal deposit system was initiated. The NDL owns the largest library collection in Japan.

Foreign Publications

The NDL selects and collects materials on Japan, as well as materials which are useful to support Diet activities and for conducting research and studies, by purchase, international exchange, and donation.


The NDL archives domestic websites.

Online Publications

The NDL collects e-books and e-magazines which are free, private online publications without Digital Rights Management (DRM).

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(2) Making and Providing Bibliographic Data

The NDL provides bibliographic data of collected materials.

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(3) Preservation and Conservation

To preserve and ensure future access to the library materials the NDL has collected, which are the shared cultural heritage of the nation, the NDL has initiatives to digitize materials, repair damaged materials, and develop a proper environment for preservation.

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Providing the public with access to information resources

(1) Services Available by Visiting the Library

The NDL provides services including access to materials held by the NDL, copy services, and reference services.

Users can apply for user registration in accordance with the normal procedure and obtain a Registered-User Card at the User Registration Counter in the Annex. You can then search for and request the materials you require from the NDL Online on a user terminal. When the materials you requested arrive, pick up the materials at the specified counter. Materials cannot be taken outside the library.

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(2) Services Available without Visiting the Library

Services Available from Local Libraries

The NDL delivers materials to public and university libraries. You can also request copying and reference services through these libraries. The NDL provides a Digitized Contents Transmission Service in Japan only, through which digitized versions of NDL holdings that are out-of-print or otherwise difficult to obtain are available at domestic libraries and institutes that are partners of the NDL.

Services Available via the Internet

The NDL provides online services available to anyone at any time.

  • NDL Online
    Remote copying services are available for registered users via NDL Online.
  • NDL Digital Collections
    NDL Digital Collections enables users to search and view a wide variety of digital materials.
  • Other Databases
    Many other databases are also available.

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(3) Services for Persons with Print Disabilities

The NDL produces talking books of academic literature for users with print disabilities and lends them through libraries across Japan. In addition, the NDL collects Digital Accessible Information System (DAISY) data and braille data made by public libraries, and provides them to libraries and individuals through an online data transmission service for persons with print disabilities.

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(4) Services for Libraries

The NDL engages in collaborative projects including training programs for librarians, and distribution of information in the field of library and information science.

  • Collaborative Reference Database
    In order for public, university, and other libraries nationwide to effectively respond to users' inquiries on materials (reference services), the NDL provides a Collaborative Reference Database in the Japanese language which enables libraries to share both information and methods for providing information.

The NDL interacts with foreign libraries extensively through international organizations such as the International Federation of Library Associations and Institutions (IFLA) and the Association of Parliamentary Librarians of Asia and the Pacific (APLAP), discussing and cooperating on common issues and international challenges facing libraries.

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