Which Japanese foreign minister was the first person to sign Japan’s surrender document in 1945?

Mamoru Shigemitsu was the first person to sign Japan’s surrender document in 1945.

Shigemitsu signed the Japanese Instrument of Surrender at 9:04 a.m. on September 2, aboard USS Missouri in Tokyo Bay. His signature was made “by command and in behalf of the Emperor of Japan and the Japanese Government.”

General Yoshijirō Umezu, Chief of the Army General Staff, signed next at 9:06 a.m. on behalf of Imperial General Headquarters. Their separate signatures reflected the distinction between Japan’s civilian government and its military command structure.

Shigemitsu had previously served as Japan’s foreign minister and had signed Japan’s surrender to the Allies in his formal diplomatic capacity. After the war, he was convicted by the International Military Tribunal for the Far East, served part of his sentence, and later returned to political life before dying in 1957.