What document did Japan accept before signing its formal surrender in World War II?

Japan accepted the Potsdam Declaration before signing its formal surrender in World War II.

The declaration was issued on July 26, 1945, by the United States, the United Kingdom, and China. It demanded Japan’s unconditional surrender and outlined broad Allied goals, including the disarmament of Japanese forces and the limitation of Japanese sovereignty to the home islands and other territories specified by the Allies.

The declaration warned that rejecting its terms would bring “prompt and utter destruction.” Japan did not immediately accept it. After the atomic bombings of Hiroshima and Nagasaki, the Soviet declaration of war, and internal political debate, Japan notified the Allies that it would accept the terms with a condition concerning the imperial institution.

The surrender instrument signed on September 2 formalized the capitulation. The Potsdam Declaration is therefore the political ultimatum Japan accepted, while the Japanese Instrument of Surrender is the document that recorded the formal act of surrender.