The Atomic Bomb and the Surrender of Japan
In 1939, a group of scientists, many having recently arrived in the United States after fleeing Nazi persecution in Germany, informed government officials that recent experiments conducted in Germany had demonstrated the feasibility of building an atomic weapon. Unless a concerted effort were made by the United States in atomic research, they warned, the Nazis could be first to possess an atomic bomb.
Although some preliminary work was done, serious progress was not made until 1942, when the atom bomb project, called the Manhattan Project, was reorganized under the command of Brigadier General Leslie R. Groves and given enormous funding. The main scientific effort took place near Santa Fe, New Mexico, where a laboratory under the direction of J. Robert Oppenheimer was constructed. On July 16, 1945, an experimental atomic bomb was exploded near Alamogordo, New Mexico.
The decision to use the atomic bomb against Japan came after studies by the military showed that, based on the kind of fierce Japanese resistance experienced in previous operations, an invasion of the Japanese home islands would probably result in hundreds of thousands of American casualties. From Potsdam, Germany, where he was conferring with the new British Prime Minister, Clement Attlee, and Stalin, President Harry S. Truman warned Japan that a new and terrible weapon would be used unless Japan surrendered unconditionally.
On August 6, a uranium bomb nicknamed "Little Boy" was dropped on the city of Hiroshima. The plane that dropped it, a B-29 called Enola Gay, was piloted by Colonel Paul W. Tibbets, Jr. At least 68,000 people were killed. Three days later, a plutonium bomb called "Fat Man" was dropped on Nagasaki, killing about 40,000.
The Surrender of JapanA plan to invade Japan in the autumn of 1945, followed in the spring by a larger invasion with troops released in Europe, did not have to be carried out. The Japanese navy had been destroyed in Leyte Gulf. Japan could no longer import the grain, coal, oil, and vital raw materials needed to sustain its war effort because a large part of its merchant marine had been destroyed and because it was under a tight air and sea blockade. The Soviet Union declared war on Japan on August 8 and immediately attacked Japanese troops in Manchuria. The two atomic bombs underlined the hopelessness of Japan's position.
On August 14 Emperor Hirohito announced that Japan would surrender unconditionally. The surrender took place September 2 aboard the U.S.S. Missouri in Tokyo Bay. Japan was reduced to its home islands and occupied by American forces.
The Air and Submarine War Against JapanAir WarEvery advance in the Pacific was made possible by the use of air power. Both carrier- and land-based planes bombarded Japanese-held islands prior to invasions and supported ground troops once the invasions were under way. In 1944 raids of 100 bombers were carried out against Japan itelf. As forward bases were taken, this number was increased until in August, 1945, a single raid used 800 planes.
Japanese losses from these raids were extremely heavy. Incendiary raids were particularly devastating, as many Japanese buildings were constructed of wood and paper. An incendiary raid against Tokyo on March 9, 1945, killed at least 80,000 people and completely destroyed large sections of the city. Other raids also caused high casualties, and destroyed much of Japan's industrial base.
Submarine WarSince Japan's far-flung island empire relied heavily on merchant shipping, the U.S. Navy quickly brought its submarines into action against this target. United States submarines sank 5,000,000 tons of Japanese merchant shipping, including more than 1,000 merchant ships of 1,000 tons or more. This tonnage, although only one-fifth that sunk by German submarines, represented more than half of the entire Japanese merchant fleet. American submarines also sank 8 Japanese carriers, 1 battleship, 14 cruisers, 42 destroyers, and 23 submarines. Forty-six United States submarines were lost by enemy action.
Japanese submarines were used more against naval vessels than against merchant shipping. Japanese submarines sank three carriers, the Yorktown, Wasp, and Liscome Bay; the heavy cruiser Indianapolis; and the antiaircraft cruiser Juneau.