Japanese Instrument of Surrender in the context of "Empire of Japan"

Japan was occupied and administered by the Allies of World War II from the surrender of the Empire of Japan on September 2, 1945, at the war's end until the Treaty of San Francisco took effect on April 28, 1952. The occupation, led by the American military with support from the British Commonwealth and under the supervision of the Far Eastern Commission, involved a total of nearly one million Allied soldiers. The occupation was overseen by the US General Douglas MacArthur, who was appointed Supreme Commander for the Allied Powers by the US president Harry S. Truman; MacArthur was succeeded as supreme commander by General Matthew Ridgway in 1951. Unlike in the occupations of Germany and Austria, the Soviet Union had little to no influence in Japan, declining to participate because it did not want to place Soviet troops under MacArthur's direct command.

This foreign presence marks the only time in the history of Japan that it has been occupied by a foreign power. However, unlike in Germany, the Allies never assumed direct control over Japan's civil administration. In the immediate aftermath of Japan's military surrender, the country's government continued to formally operate under the provisions of the Meiji Constitution.

The surrender of the Empire of Japan in World War II was announced by Emperor Hirohito on 15 August and formally signed on 2 September 1945, ending the war. By the end of July 1945, the Imperial Japanese Navy (IJN) was incapable of conducting major operations and an Allied invasion of Japan was imminent. Together with the United Kingdom and China, the United States called for the unconditional surrender of Japan in the Potsdam Declaration on 26 July 1945—the alternative being "prompt and utter destruction". While publicly stating their intent to fight on to the bitter end, Japan's leaders (the Supreme Council for the Direction of the War, also known as the "Big Six") were privately making entreaties to the publicly neutral Soviet Union to mediate peace on terms more favorable to the Japanese. While maintaining a sufficient level of diplomatic engagement with the Japanese to give them the impression they might be willing to mediate, the Soviets were covertly preparing to attack Japanese forces in Manchuria and Korea (in addition to South Sakhalin and the Kuril Islands) in fulfillment of promises they had secretly made to the US and the UK at the Tehran and Yalta Conferences.

On 6 August 1945, at 8:15 am local time, the United States detonated an atomic bomb over the Japanese city of Hiroshima. Sixteen hours later, American president Harry S. Truman called again for Japan's surrender, warning them to "expect a rain of ruin from the air, the like of which has never been seen on this earth." Late on 8 August 1945, in accordance with the Yalta agreements, but in violation of the Soviet–Japanese Neutrality Pact, the Soviet Union declared war on Japan, and soon after midnight on 9 August 1945, the Soviet Union invaded the Japanese puppet state of Manchukuo. Hours later, the U.S. dropped a second atomic bomb on the Japanese city of Nagasaki.

On 6 and 9 August 1945, the United States detonated two atomic bombs over the Japanese cities of Hiroshima and Nagasaki, respectively, during World War II. The aerial bombings killed 150,000 to 246,000 people, most of whom were civilians, and remain the only uses of nuclear weapons in an armed conflict. Japan announced its surrender to the Allies on 15 August, six days after the bombing of Nagasaki and the Soviet Union's declaration of war against Japan and invasion of Manchuria. The Japanese government signed an instrument of surrender on 2 September, ending the war.

In the final year of World War II, the Allies prepared for a costly invasion of the Japanese mainland. This undertaking was preceded by a conventional bombing and firebombing campaign that devastated 64 Japanese cities, including an operation on Tokyo. The war in Europe concluded when Germany surrendered on 8 May 1945, and the Allies turned their full attention to the Pacific War. By July 1945, the Allies' Manhattan Project had produced two types of atomic bombs: "Little Boy", an enriched uranium gun-type fission weapon, and "Fat Man", a plutonium implosion-type nuclear weapon. The 509th Composite Group of the U.S. Army Air Forces was trained and equipped with the specialized Silverplate version of the Boeing B-29 Superfortress, and deployed to Tinian in the Mariana Islands. The Allies called for the unconditional surrender of the Imperial Japanese Armed Forces in the Potsdam Declaration on 26 July 1945, the alternative being "prompt and utter destruction". The Japanese government ignored the ultimatum.

The Soviet invasion of Manchuria, formally known as the Manchurian Strategic Offensive Operation or simply the Manchurian Operation (Маньчжурская операция) and sometimes, mainly in the West, as Operation August Storm, began on 9 August 1945 with the Soviet invasion of the Empire of Japan's puppet state of Manchukuo, which was situated in Japanese-occupied Manchuria. It was the largest campaign of the 1945 Soviet–Japanese War, which resumed hostilities between the Union of Soviet Socialist Republics and the Empire of Japan after almost six years of peace.

The invasion began hours before the atomic bombing of Nagasaki and 3 days after the atomic bombing of Hiroshima. The Soviet entry into this theater of the war and the defeat of the Kwantung Army were significant factors in the Japanese government's decision to surrender unconditionally on 15 August, as it became apparent that the Soviet Union had no intention of acting as a third party in negotiating an end of the war on conditional terms. The Kwantung Army officially surrendered on 16 August, although fighting continued until 2 September, when was firmed the Japanese Instrument of Surrender.

Mamoru Shigemitsu (重光 葵, Shigemitsu Mamoru; July 29, 1887 – January 26, 1957) was a Japanese diplomat and politician who served as Minister of Foreign Affairs three times during and after World War II and as Deputy Prime Minister. As a civilian plenipotentiary representing the Japanese government, Shigemitsu cosigned the Japanese Instrument of Surrender on board the battleship USS Missouri on September 2, 1945.

USS Missouri (hull number BB-63) is an Iowa-class battleship built for the United States Navy (USN) in the 1940s and is now a museum ship. Completed in 1944, she is the last battleship commissioned by the United States. The ship was assigned to the Pacific Theater during World War II, where she participated in the Battles of Iwo Jima and Okinawa and shelled the Japanese home islands. Her quarterdeck was the site where the Japanese Instrument of Surrender was signed, officially ending World War II.

After World War II, Missouri served in various diplomatic, show of force and training missions. In 1950, the ship ran aground during high tide in Chesapeake Bay and after great effort was re-floated several weeks later. She later fought in the Korean War during two tours between 1950 and 1953. Missouri was the first American battleship to arrive in Korean waters and served as the flagship for several admirals. The battleship took part in numerous shore bombardment operations and also served in a screening role for aircraft carriers. Missouri was decommissioned in 1955 and transferred to the reserve fleet (also known as the "Mothball Fleet").