What name is given to the September 2, 1945 document that legally ended Japan's war?

The September 2, 1945 document that legally ended Japan's war is called the Instrument of Surrender. Japanese representatives signed it aboard USS Missouri in Tokyo Bay before Allied witnesses.

The instrument stated that Japan accepted the provisions of the Potsdam Declaration and ordered all Japanese forces to cease hostilities. It also required Japanese commanders to surrender their weapons and obey the orders of the Supreme Commander for the Allied Powers.

The document was not the later peace treaty that restored Japan's sovereignty. That treaty, the Treaty of San Francisco, was signed in 1951 and entered into force in 1952. The Instrument of Surrender instead established the immediate legal and military conditions of capitulation and occupation.