What was the official document signed aboard USS Missouri when Japan surrendered in 1945?

The official document signed aboard USS Missouri was the Japanese Instrument of Surrender.

This printed agreement formalized Japan’s capitulation and set out its acceptance of the Allied surrender terms. Japanese and Allied representatives signed it during the ceremony in Tokyo Bay on September 2, 1945. Its signing is generally treated as the formal end of World War II.

The Instrument was not the same document as the Potsdam Declaration. The declaration, issued on July 26, 1945, demanded Japan’s surrender and described the Allies’ conditions. Japan’s acceptance of those terms led to the later signing of the Instrument, which recorded the surrender in legal and ceremonial form.

Two Japanese representatives signed: Foreign Minister Mamoru Shigemitsu for the Japanese government and General Yoshijiro Umezu for Imperial General Headquarters. Allied representatives then signed for nine governments, including the United States, China, Britain, and the Soviet Union.