What Allied command title did Douglas MacArthur use when signing Japan’s surrender?

Douglas MacArthur used the title Supreme Commander for the Allied Powers when signing Japan’s surrender.

MacArthur signed the Instrument of Surrender on September 2, 1945, aboard USS Missouri in Tokyo Bay. He signed first for the Allied powers, after Mamoru Shigemitsu and Yoshijiro Umezu had signed for Japan.

The title referred to MacArthur’s authority over the Allied occupation and surrender arrangements in Japan. It was commonly abbreviated as SCAP, which also came to describe the occupation headquarters and the administration that directed postwar reforms.

MacArthur had been appointed Supreme Commander for the Allied Powers after Japan’s surrender. He oversaw the occupation of Japan, including demilitarization, political reforms, and the preparation of a new constitutional order. Fleet Admiral Chester Nimitz signed next as the United States representative, while representatives of eight other Allied governments followed.