Which Japanese official signed the surrender document first for Japan aboard USS Missouri?

Mamoru Shigemitsu was the first Japanese official to sign the surrender document aboard USS Missouri.

Shigemitsu was Japan's foreign minister and signed at approximately 9:04 a.m. on 2 September 1945. The document recorded that he signed by command and on behalf of the emperor and the Japanese government. General Yoshijiro Umezu, chief of the Army General Staff, signed shortly afterward for Japanese Imperial General Headquarters.

The Japanese delegation contained eleven representatives, but only Shigemitsu and Umezu signed the instrument. Their separate roles reflected the division between Japan's civilian government and military command. After the two Japanese signatures, Douglas MacArthur signed as Supreme Commander for the Allied Powers, followed by representatives of the Allied nations. Shigemitsu had previously represented Japan during the war and had served as foreign minister in several cabinets. His presence at the ceremony illustrated how the surrender required both political and military authorization, rather than the signature of a single institution alone.