Japan’s surrender was first announced in the Americas on August 14, 1945. The announcement arrived on the American side of the International Date Line before the surrender broadcast was heard in Japan on August 15.
This difference explains why V-J Day is associated with more than one date. In Japan and many Commonwealth countries, August 15 is commonly observed because Emperor Hirohito’s recorded announcement was broadcast that day in Japan. In the United States, the news was announced on August 14 because of time-zone differences.
September 2 is another important date: Japanese representatives formally signed the Instrument of Surrender aboard USS Missouri in Tokyo Bay. That ceremony legally and ceremonially ended hostilities, while the earlier August announcements communicated Japan’s acceptance of the Allied terms.
These dates are sometimes confused because “V-J Day” can refer to the announcement, the celebration, or the formal signing, depending on the country and context.