What was the formal written agreement signed by Japan on September 2, 1945?

The formal written agreement signed by Japan on September 2, 1945, was the Japanese Instrument of Surrender.

The instrument recorded Japan’s unconditional capitulation and brought the formal hostilities of World War II to an end. Japanese representatives signed it aboard the American battleship USS Missouri in Tokyo Bay, followed by representatives of the Allied governments.

It was a capitulation document rather than a peace treaty. The later Treaty of San Francisco, signed in 1951 and effective in 1952, established the postwar peace settlement between Japan and many Allied countries. Confusing those two documents can obscure the difference between ending combat and arranging the long-term legal settlement.

The instrument contained Japanese commitments to carry out the emperor’s orders, surrender military forces, and comply with Allied occupation requirements. Its signing made the earlier political announcement and broadcast surrender legally and ceremonially concrete.