The Potsdam Declaration demanded Japan’s unconditional surrender on July 26, 1945, before V-J Day.
The declaration was issued by the United States, the United Kingdom, and China during the Potsdam Conference. It warned Japan that rejecting the demand would bring “prompt and utter destruction,” while also outlining broad Allied goals for Japan’s postwar disarmament and occupation.
The Soviet Union did not initially sign the declaration because it was still neutral in the war against Japan. The Soviet Union declared war on Japan on August 8, 1945, and joined the conflict shortly before Japan’s surrender announcement.
Japan’s government eventually accepted the declaration’s terms in August 1945, after the atomic bombings of Hiroshima and Nagasaki, the Soviet entry into the war, and intense internal debate. Emperor Hirohito announced acceptance on August 15, and the formal surrender followed on September 2.