The First Period (Sato Eisaku Papers)
Unpublished materials left by Minoru Kusuda (1924-2003), the chief secretary who supported the Eisaku Sato administration (1964-1972).
The documents are virtually the "Sato Eisaku Papers," consisting of first-class, top-secret materials on everything from diplomacy to domestic politics.
This is a large collection of over 4,000 items, and is an indispensable basic historical document for the future of postwar history.

The Second Period
The second period of the collection consists of a vast amount of previously unpublished materials, beginning with the Kishi and Ikeda administrations before Kusuda Minoru became secretary general, and continuing with the Sato administration, which is a supplement to the first period, as well as materials from the Fukuda administration, Shintaro Abe, and the Takeshita administration after Sato left office. It is an indispensable collection of primary historical documents that fills in the material gaps in Japanese politics, especially from the late 1970s to the early 1990s.
Part I The Kishi and Ikeda Administrations, the Sato Administration, and the Fukuda Administration