Allows users to search the National Diet Library (NDL) Catalog, Japanese public library catalogs, NDL Periodical Indexes (国立国会図書館雑誌記事索引) and NDL Digital Archives all at once or separately. Search pages are available in Japanese, English, simplified Chinese or Korean. Login is not required. Search tips are located here. Note: The database is down for scheduled maintenance from 6:30-7:00 (Japan time) on the third Sunday of each month.