Victoy Over Japan Day, or V-J Day, is the day on which the Empire of Japan surrendered to the Allied Forces during the Second World War. The Japanese authorities announced that they would surrender on 15 August 1945, but the formal signing of their unconditional surrender was made on 2 September 1945. 15 Augustis the official V-J Day for the United Kingdom, while the official US commemoration is 2 September.