Which Japanese cabinet was in office when Japan signed its formal surrender in September 1945?

The Higashikuni Cabinet was in office when Japan signed its formal surrender in September 1945.

Prince Naruhiko Higashikuni became prime minister on August 17, 1945, two days after Emperor Hirohito’s surrender broadcast. His cabinet therefore governed Japan during the September 2 signing aboard USS Missouri.

The cabinet’s immediate responsibilities included managing the end of hostilities, demobilizing Japan’s armed forces, and cooperating with the Allied occupation authorities. It was formed during an exceptionally brief transition between the announcement of surrender and the beginning of occupation administration.

The Higashikuni Cabinet lasted only from August 17 to October 9, 1945. It is especially notable because Higashikuni was the only member of Japan’s imperial family to serve as prime minister. The preceding Kantarō Suzuki Cabinet had overseen the final wartime decision to accept the Potsdam Declaration, but it was no longer in office when the surrender document was signed.