The 1945 celebration of victory over Japan is commonly called V-J Day.
The abbreviation means “Victory over Japan,” paralleling V-E Day, which marked victory in Europe earlier in 1945. In the United States, celebrations followed President Harry Truman's announcement that Japan had accepted the Allied surrender terms. Crowds filled streets, factories, public squares, and military bases as news spread.
The date associated with V-J Day varies. Japan and many Commonwealth countries traditionally observe August 15, the date Hirohito's surrender broadcast was heard locally. The United States often uses August 14 because Truman's announcement reached the American public on that date. September 2 marks the formal signing of the surrender document and is also called V-J Day, especially in historical and military contexts.
V-J Day therefore describes both a historical event and a commemorative date. It should not be confused with V-E Day, which commemorates Germany's surrender in Europe on May 8, 1945.