In the United States, August 14, 1945, is commonly called V-J Day for Japan’s surrender announcement. President Harry S. Truman announced the Japanese government’s acceptance of Allied terms to the American public that evening.
The date differs internationally because the announcement crossed the International Date Line and occurred at different local times. In Japan, Emperor Hirohito’s broadcast was heard on August 15, while many Allied countries also commemorate August 15. American newspapers and celebrations generally used August 14.
This date should not be confused with September 2, 1945. September 2 was the day Japanese representatives formally signed the Instrument of Surrender aboard USS Missouri in Tokyo Bay. President Truman later designated September 2 as the official V-J Day, although popular usage in the United States strongly associated V-J Day with the August 14 announcement.
The distinction explains why reputable historical accounts give both August 14 and August 15 for V-J Day. The difference is chiefly a matter of local time and commemorative tradition, not a disagreement about the surrender itself.