Which Allied declaration did Japan accept before signing its formal surrender in 1945?

Japan accepted the Potsdam Declaration before signing its formal surrender in 1945.

The declaration was issued on July 26, 1945, by the United States, the United Kingdom, and China. It demanded the unconditional surrender of Japan's armed forces and warned that rejecting the terms would bring “prompt and utter destruction.”

The statement also outlined postwar conditions. Japanese sovereignty was to be limited to the home islands and other islands designated by the Allies, while the country's military was to be disarmed. The declaration did not directly specify what would happen to Emperor Hirohito, an omission that complicated Japanese deliberations.

After the atomic bombings of Hiroshima and Nagasaki and the Soviet declaration of war against Japan, the Japanese government accepted the declaration. Hirohito announced that decision on August 15, and the surrender instrument was signed on September 2.