The Potsdam Declaration defining terms for Japan’s surrender appeared on July 26, 1945.
The United States, the United Kingdom, and China issued the declaration during the Potsdam Conference. It called for Japan’s armed forces to surrender and warned that refusal would bring “prompt and utter destruction.” The Soviet Union did not sign the initial declaration because it was still neutral in the war against Japan at that moment.
The declaration set out major postwar principles, including the occupation of selected Japanese territory, disarmament of Japanese forces, and the limitation of Japanese sovereignty to the home islands and other islands determined by the Allies.
Japan did not immediately accept the ultimatum. After the atomic bombings, the Soviet entry into the war, and internal debate among Japanese leaders, Emperor Hirohito authorized acceptance. The September surrender instrument then put the declaration’s terms into effect.