Zasshi Kiji Sakuin (雑誌記事索引, "Japanese Periodicals Index"), often called Zassaku in short, is a searchable database of scholarly articles in Japanese. The database, produced by the National Diet Library (NDL) in 1948, catalogs selected articles from NDL's extensive collection of periodicals. The database was created for the purpose of facilitating scholastic research in providing citation information. Scholarly journals, specialized magazines, institutional periodical publications and general-interest magazines are included in the database from all areas of academic interest: humanities, social sciences, science and technology, and medical sciences, including pharmacology. Approximately 10,000 periodicals and more than 6,660,000 articles are currently registered in Zasshi Kiji Sakuin. It is updated every two weeks. Zasshi Kiji Sakuin's extensive coverage of periodicals provides an excellent bibliography of research and publications in Japan, which may not necessarily appear in non-Japanese journals of Japanese studies.