Over 360 volumes of compilations and related materials, investigation documents, collected materials, such as historical overviews produced by the Ministry of Justice, from Judicial System and Research Department research on war crimes trial material transferred from the Ministry of Justice to the National Archives.

Part I: Historical overview and compilation-related material/research material.
Contains historical compilations and compilation-related material assembled by the Ministry of Justice, starting with the key sources for research on the Tokyo Trial Senso hanzai saiban gaishi ("A brief history of the war crimes trials") (those parts already in the public domain), Senso hanzai saiban gaishiyo ("A brief history of the war crimes trials - main points") and Senpan shakuho shiyo ("Brief history of the release of war criminals"). Also includes research resources such as minutes from a study group on the war crimes trials. Approximately 140 volumes.

Part II: Investigation reports
Contains records of interviews with over 100 witnesses from the former Imperial navy and army, and the foreign ministry, starting with former Class A convicted war criminals, legal counsel, and others connected to the Tokyo Trial. This includes not only pivotal agents of the state such as politicians and palace officials, but extends to diplomats, undersecretaries, and military field officers. Also included are handwritten or typed investigation reports, plus correspondence and notes. Approximately 100 volumes.

Part III: Collected resources/Notes by staff responsible for material on war criminals
Group of primary source materials on the Tokyo Trial and war crimes, gathered by the Ministry of Justice, with particular emphasis on records of the debate around war crimes and the "definition of aggression" at the UN, and Japan's response to these. Handwritten notes by those responsible for materials connected with war criminals are composed of memos from interviews etc. and serve as a supplement to the investigation reports in Part 2. Approximately 120 volumes.