The National Diet Library (国立国会図書館, Kokuritsu Kokkai Toshokan) is the only national library in Japan. It was established in 1948.
The purpose of the library is to assist members of the Diet of Japan (国会, Kokkai). The library is similar in purpose and scope to the U.S. Library of Congress.
The National Diet Library has two main facilities. One is in Tokyo and the other is in Kyoto. There are also several branch libraries in Japan.