What was the official name of the document signed by Japan on September 2, 1945?

The official name of the document signed by Japan on September 2, 1945, was the Japanese Instrument of Surrender.

The document formally ended hostilities between Japan and the Allied powers. It recorded Japan’s acceptance of the Potsdam Declaration and ordered Japanese forces to cease resistance, surrender their weapons, and comply with Allied instructions. Japanese representatives signed it aboard USS Missouri in Tokyo Bay.

Foreign Minister Mamoru Shigemitsu signed for the Japanese government, and General Yoshijiro Umezu signed for the Imperial Japanese General Headquarters. General Douglas MacArthur signed for the Allied powers, followed by representatives of the United States and other Allied nations.

The instrument is not the same as the later peace treaty between Japan and many Allied countries. The San Francisco Peace Treaty, signed in 1951 and effective in 1952, formally ended the state of war for its participating countries and restored Japan’s sovereignty. The 1945 instrument instead established the immediate military surrender and occupation arrangements.