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Digitization of library materials

The National Diet Library (NDL) has been converting the content of materials into other media to achieve compatibility of use and preservation. A microfilming program was originally used as a method for preserving valuable materials, but since 2009, the NDL has been in general digitizing them for the following purposes.

  1. Preservation of materials
    The NDL has been digitizing materials and providing digitized contents as an alternative for use to prevent original materials from deterioration and damage by frequent use
  2. Digital library service
    Digitization improves convenience in reading materials. The NDL has been providing on the Internet digitized contents which cleared copyright so that people can access them anytime and anywhere on the web without visiting the NDL in person.

Overview of the digitized contents

Material type Explanation
Books Books acquired by the NDL up to 1968
Parts of books related to earthquakes and natural disasters (including books acquired after 1968)
Periodicals Periodicals published more than five years ago
Rare Books and Old Materials Rare books, Semi-rare books, Japanese old books up to the Edo Period and Chinese old books up to the Qing Dynasty
Doctoral Dissertations Japanese doctoral dissertations received by the NDL between FY1988 and FY2000
Official Gazettes Japanese official gazettes from the first issue published on July 2, 1883 to the issue of April 30, 1952
Modern Japanese Political History Materials Letters, documents, diaries, etc. held by Japanese politicians, bureaucrats, soldiers, etc. from the end of the Tokugawa period to the Showa era
Audio-Visual materials Cassette tapes, sono-sheets (including the attached booklet), laserdiscs (including the attached booklet), part of the broadcast scripts up to 1980 (TV / radio program screenplays / scripts) which were donated to the NDL by the Consortium for the Promotion of Broadcast Script Archives in Japan, part of the manuscript of Japanese composers after the Meiji era and related materials
Maps Maps published in Japan from the Meiji era to the early Showa era
others Digitized Collections from Other Institutions
  • Materials on the Allied Occupation of Japan:From the documents on the Allied Occupation of Japan held by the National Archives and Records Administration of the United States, parts of the Records of U.S. Strategic Bombing Survey, the Records of General Headquarters, Far East Command, etc.
  • The Gordon W. Prange Collection:Parts of the books in the Gordon W. Prange Collection (Japanese publications submitted to the Allied Forces for censorship)
  • Historical Recordings Collection:Sound recordings of music, speeches, etc. on 78rpm records and metal discs used to press commercial releases from around 1900 to 1950
  • Collections from Other Institutions:Science Films, Digitized materials of the University of Tokyo Library System, EXPO Aichi, Naimusho Keihokyoku Censorship Collection, etc.

There are some materials not digitized even if included in the above explanation. For more information please see the National Diet Library Digital Collections.

We have the dedicated homepage in which you could search and listen to the Historical Recordings Collection (Rekion).

For details of the material type, please refer to "About the National Diet Library Digital Collections".

Current situation of digitized contents (as of July 2021)

Material type Number of contents 1
Available Online Available only at the NDL and partner libraries2 Available only at the NDL Total
Total 560,000 1,510,000 720,000 2,790,000
Books 360,000 550,000 80,000 990,000
Periodicals 10,000 810,000 520,000 1,340,000
Rare Books and Old Materials 80,000 20,000 90,000
Doctoral Dissertations 10,000 120,000 30,000 160,000
Official Gazettes 20,000 20,000
Modern Japanese Political History Materials 7,000 1,000 8,000
Audio-Visual materials 3,000 6,000 9,000
Maps 1,000 1,000
others 70,000 20,000 90,000 170,000


  1. This figure is the round number of items the NDL has been providing.
  2. These materials are available only within the facilities of the NDL and on the site of the partner libraries that subscribe to the Digitized Contents Transmission Service for Libraries (in Japanese).

(Reference) Other breakdown

Material type Number of contents
Available Online Available only at the NDL and partner libraries Available only at the NDL Total
Materials on the Allied Occupation of Japan 60,000 10,000 70,000
The Gordon W. Prange Collection 10,000 30,000 40,000
Historical Recordings Collection 5,000 40,0001 50,000
Collections from Other Institutions 1,000 1,000 2,000


  1. These are the records you can listen to in the Historical Recordings Collection (Rekion) partner libraries and NDL.

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