What was the written agreement that formalized Japan's 1945 surrender called?

The written agreement that formalized Japan’s 1945 surrender was called the Japanese Instrument of Surrender.

The document recorded Japan’s acceptance of the terms announced by the Allied powers and confirmed the surrender of Japanese armed forces. It was signed aboard USS Missouri in Tokyo Bay on 2 September 1945. The document’s wording made the surrender a formal legal and military act rather than only a broadcast announcement.

The Japanese Instrument of Surrender is distinct from the Potsdam Declaration. The Potsdam Declaration, issued in July 1945, stated the terms Japan was expected to accept. The Instrument of Surrender was the document Japan actually signed. It is also different from the Treaty of San Francisco, which formally ended the state of war between Japan and many Allied countries in 1952.

Two Japanese representatives signed: Foreign Minister Mamoru Shigemitsu for the government and General Yoshijirō Umezu for Imperial General Headquarters. Allied representatives then signed on behalf of their governments.