What was the formal document that ended hostilities between Japan and the Allies in 1945?

The Japanese Instrument of Surrender was the formal document that ended hostilities between Japan and the Allies in 1945.

The document recorded Japan's acceptance of the terms announced in the Potsdam Declaration and required Japanese forces to cease hostilities and disarm. It was signed on September 2, 1945, aboard USS Missouri in Tokyo Bay.

The Potsdam Declaration was different: it was an Allied proclamation issued on July 26 demanding Japan's surrender. Japan's formal acceptance was later recorded through the Instrument of Surrender. The Treaty of San Francisco was a later peace treaty, signed in 1951 and effective in 1952, so it did not serve as the document ending the 1945 fighting.

Two versions of the Instrument were signed, one for the Allied powers and one for Japan. A signing error by Canadian representative Lawrence Moore Cosgrave caused the printed labels on one copy to be corrected by hand. The documents are preserved in archival collections, while copies and related artifacts remain associated with USS Missouri.