The Empire of Japan entered World War II by attacking Pearl Harbor in December 1941. The Japanese then launched offensives against Allied forces in East and Southeast Asia, with simultaneous attacks on Hong Kong, British Malaya and the Philippines. On February 15, 1942, Singapore, due to the overwhelming superiority of Japanese forces and encirclement tactics, fell to the Japanese, causing the largest surrender of British-led military personnel in history. The Japanese then seized the key oil production zones of Borneo, Central Java, Malang, Cepu, Sumatra, and Dutch New Guinea of the late Dutch East Indies, defeating the Dutch forces. The Japanese then consolidated their lines of supply through capturing key islands of the Pacific, including Guadalcanal.
In May 1942, failure to decisively defeat the Allies at the Battle of the Coral Sea, in spite of Japanese numerical superiority, equated to a strategic defeat for Imperial Japan. This setback was followed in June 1942 by the catastrophic loss of four fleet carriers at the Battle of Midway, the first decisive defeat for the Imperial Japanese Navy. It proved to be the turning point of the war as the Navy lost its offensive strategic capability.
In mid-August 1945, the United States dropped nuclear weapons on the Japanese cities of Hiroshima (August 6) and Nagasaki (August 9). Having ignored the Potsdam Declaration, the Empire of Japan surrendered and ended World War II, after the atomic bombings of Hiroshima and Nagasaki and the declaration of war by the Soviet Union. In a national radio address on August 15, Emperor Hirohito announced the surrender to the Japanese people.