This collection comprises archival materials related to the Cabinet Research Office (Naicho), one of Japan’s principal intelligence organizations. The documents originate from the personal archive of Shigaki Tamiro (1922–2020), a founding member of the Office who later served as its Chief Executive. In addition to primary source materials, the collection includes Shigaki’s original diaries, covering the period from the establishment of the Cabinet Research Office in 1952 through his retirement as President of the National Publishing Association in 1990, which oversaw commissioned research activities for the Office from its earliest years.