The surrender of Japan in August 1945 brought World War II to a close. By August 1945, the Imperial Japanese Navy effectively ceased to exist, and an Allied invasion of Japan was imminent. While publicly stating their intent to fight on to the bitter end, Japan's leaders at the Supreme War Council (the "Big Six") were privately making entreaties to the Soviet Union to mediate peace on terms favorable to the Japanese. The Soviets, meanwhile, were preparing to attack the Japanese, in fulfillment of their promise to the Americans and the British made at the Yalta Conference.
On August 6 and 9, the Americans dropped atomic bombs on Hiroshima and Nagasaki, respectively. Also on August 9, the Soviet Union launched a surprise invasion of the Japanese colony in Manchuria (Manchukuo), in violation of the Soviet–Japanese Neutrality Pact. These twin shocks caused Emperor Hirohito to intervene and order the Big Six to accept the terms the Allies had set down for ending the war in the Potsdam Declaration. After several more days of behind-the-scenes negotiations and a failed coup d'état, Hirohito gave a recorded radio address to the nation on August 15. In the radio address, called the Gyokuon-hōsō (Jewel Voice Broadcast), he read the Imperial Rescript on surrender, announcing Japan's surrender to the Japanese populace.On August 28, the occupation of Japan by the Supreme Commander of the Allied Powers began. The surrender ceremony was held on September 2 aboard the U.S. battleship Missouri, at which officials from the Japanese government signed the Japanese Instrument of Surrender, officially ending World War II. Allied civilians and servicemen alike celebrated V-J Day, the end of the war. However, some isolated commands and personnel from Japan's far-flung forces throughout Asia and the Pacific islands refused to surrender for months and years after, into the 1970s. Since Japan's surrender, historians have debated the ethics of using the atomic bombs.