What was the 1945 Allied proclamation that Japan accepted when it surrendered called?

The 1945 Allied proclamation that Japan accepted when it surrendered was the Potsdam Declaration. The United States, the United Kingdom, and China issued it on July 26, 1945, during the Potsdam Conference.

The declaration demanded Japan's unconditional surrender and set out broad terms for the country's disarmament and postwar occupation. It warned that rejecting the demand would bring “prompt and utter destruction,” although it did not specify the atomic bomb then being prepared for use.

Japan's government initially did not accept the declaration. After the atomic bombings of Hiroshima and Nagasaki and the Soviet Union's entry into the war against Japan, Japanese leaders moved toward surrender. The imperial rescript of August 15 stated that Japan would accept the Potsdam terms.

The declaration was not itself a peace treaty. It was a wartime ultimatum and framework for surrender; the later Treaty of San Francisco formally established peace between Japan and many Allied countries in 1951.