What was the name of the document that formalized Japan’s surrender in 1945?

The document that formalized Japan’s surrender in 1945 was the Japanese Instrument of Surrender.

The instrument was the printed agreement signed on September 2, 1945, aboard USS Missouri in Tokyo Bay. It recorded Japan’s capitulation and brought the formal hostilities of World War II to an end. Japanese representatives and Allied representatives each signed copies.

The instrument implemented Japan’s acceptance of the surrender terms announced in the Potsdam Declaration. It was not a later peace treaty. The Treaty of San Francisco, signed in 1951, restored peace formally with Japan and ended the Allied occupation under a separate postwar settlement.

The ceremony included two Japanese signatories: Foreign Minister Mamoru Shigemitsu for the government and General Yoshijiro Umezu for the military. Douglas MacArthur accepted the surrender for the Allied powers. A Canadian signing error caused the printed titles on one copy to be corrected by hand, a small detail that distinguishes the surviving versions.