Even after the Allied victory in Europe, World War II continued to rage in the Pacific Theater. American forces had made a slow, but steady push toward Japan after turning the course of the war with victory at the June 1942 Battle of the Midway. The Battles of Iwo Jima and Okinawa in the winter and spring of 1945 were among the bloodiest of the war, and the American military projected that as many as 1 million casualties would accompany any invasion of the Japanese mainland.
Weeks after the first successful test of the atomic bomb occurred in Alamogordo, New Mexico, on July 16, 1945, President Harry Truman, who had ascended to the presidency less than four months earlier after the death of Franklin D. Roosevelt, authorized its use against Japan in the hopes of bringing a swift end to the war. On August 6, 1945, the American B-29 bomber Enola Gay dropped an atomic bomb on the manufacturing city of Hiroshima, immediately killing an estimated 80,000 people. Tens of thousands later died of radiation exposure. When Japan failed to immediately surrender after the bombing of Hiroshima, the United States detonated an even more powerful atomic bomb on Nagasaki three days later that killed 35,000 instantly and another 50,000 in its aftermath.
The End of World War II: Soviets Declare War and Japan Surrenders
In addition to the bombings of Hiroshima and Nagasaki, Japan came under increasing pressure when the Soviet Union formally declared war on August 8 and invaded Japanese-occupied Manchuria in northeastern China. With his Imperial Council deadlocked, Japan’s Emperor Hirohito broke the tie and decided that his country must surrender. At noon on August 15 (Japanese time), the emperor announced Japan’s surrender in his first-ever radio broadcast.
On September 2, World War II ended when U.S. General Douglas MacArthur accepted Japan’s formal surrender aboard the U.S. battleship Missouri, anchored in Tokyo Bay along with a flotilla of more than 250 Allied warships.