About National Institute for Defense Studies:
The National Institute for Defense Studies (NIDS) holds historical documents related to the Imperial Army and Navy. These documents are useful to understand Japan’s military history. After Japan's surrender in 1945, most of the documents were destroyed, and some were scattered. Many of the papers that survived were taken by the Allied Occupation Forces and are held in the US National Archives. In April 1958, following extensive negotiations with the United States the documents in this collection were finally returned to Japan.