The Bombing of Hiroshima and Nagasaki

Hiroshima & Nagasaki Explosions

Since 1941, when the Japanese attacked Pearl Harbor, the forces of the United States and her allies had been at war with Japan. The combined land, sea and air forces of the Allies fought back against Japan until only the Japanese homeland remained in Japanese control.

On July 26, Truman issued the Potsdam Declaration, which called for Japan's unconditional surrender and listed peace terms. He had already been informed of the successful detonation of the first atomic bomb at Alamogordo, New Mexico, ten days earlier. The Japanese were warned of the consequences of continued resistance by the terms of the Potsdam Declaration, signed by President Truman and by Prime Minister Attlee of the United Kingdom and with the concurrence of Chiang Kai-Shek, President of the National Government of China.

The bombing of Nagasaki

When Japan rejected the ultimatum, Truman authorized use of the bomb. Secretary of War Henry L. Stimson felt the choice of using the atomic bomb against Japan would be the "least abhorrent choice." This would be weighed against sacrificing the lives of thousands of soldiers. Military advisers had told Truman that a potential loss of about 500,000 American soldiers was at stake.

It was vital to produce the greatest possible blow upon the Japanese, if the war was to be effectively shortened and the lives of the U.S. soldiers were to be saved. The atomic bomb provided such a blow. The cities of Hiroshima and Nagasaki were selected as targets after exhaustive study by military specialists. Hiroshima and Nagasaki had been virtually untouched by the U.S. and Allied bombing runs.

On August 6, 1945, at 9:15 AM Tokyo time, a B-29 plane, the "Enola Gay" piloted by Paul W. Tibbets, dropped a uranium atomic bomb, code named "Little Boy" on Hiroshima, Japan's seventh largest city. In minutes, half of the city vanished. According to U.S. estimates, 60,000 to 70,000 people were killed or missing, 140,000 were injuried many more were made homeless as a result of the bomb. Deadly radiation reached over 100,000. In the blast, thousands died instantly.

The city was unbelievably devastated. Of its 90,000 buildings, over 60,000 were demolished. Another bomb was assembled at Tinian Island on August 6. On August 8, Field Order No.17 issued from the 20th Air Force Headquarters on Guam called for its use the following day on either Kokura, the primary target, or Nagasaki, the secondary target. Three days after Hiroshima, the B-29 bomber, "Bockscar" piloted by Sweeney, reached the sky over Kokura on the morning of August 9 but abandoned the primary target because of smoke cover and changed course for Nagasaki.

Nagasaki bomb

Nagasaki was an industrialized city with a natural harbor in Western Kuushu, Japan. At 11:02 a.m., this bomb, known as the "Fat Man" bomb, exploded over the north factory district at 1,800 feet above the city to achieve maximum blast effect. Buildings collapsed. Electrical systems were shorted. A wave of secondary fires resulted, adding to their holocaust.

Flash burns from primary heat waves caused most of the casualties to inhabitants. Others were burned when their homes burst into flame. Flying debris caused many injuries. A fire storm of winds followed the blast at Hiroshima as air was drawn back to the center of the burning area. Trees were uprooted. The bomb took the lives of 42,000 persons and injured 40,000 more.

It destroyed 39 percent of all the buildings standing in Nagasaki. According to U.S. estimates, 40,000 people were killed or never found as a result of the second bomb. Highly penetrating radiation from the nuclear explosion had a heavy casualty effect. Energy released by the explosion of this type of atomic bomb used over Nagasaki is roughly equivalent to the power generated by exploding 20,000 tons of TNT or 40 million pounds of TNT. It would fill two good sized cargo ships.

In the early stages of the explosion, temperatures of tens of millions of degrees were produced. The light emitted is roughly ten times the brightness of the sun. During the explosion, various types of radiations such as gamma rays and alpha and beta particles eminate from the explosion. These radiative particles give the atomic bomb its greatest deadliness. They may last years or even centuries in dangerous amounts. Gamma radiation and neutrons caused thousands of cases of radiation sickness in Japan. First the blood was affected, and then the blood making organs were impaired including the bone marrow, the spleen and the lymph nodes. When radiation was severe, the organs of the body became necrotic within a few days, marking the victim for certain death within a short period of time.

Surveys disclosed that severe radiation injury occurred to all exposed persons within a radius of one kilometer. Serious to moderate radiation injury occurred between one and two kilometers. Persons within two to four kilometers suffered slight radiation effects.

Hiroshima bomb picture

What the bomb had produced was concentrated chaos, from which no city or nation could easily or rapidly recover. No significant repair or reconstruction was accomplished until months later. On September 2, the Japanese government, which had seemed ready to fight to the death, surrendered unconditionally. Winston Churchill estimated that the lives of a million Americans and two hundred and fifty thousand British soldiers and sailors had been saved by this sudden shortening of the war.

Actual Nagasaki & Hiroshima bombing footage available in Trinity and Beyond.
Monument at the Hiroshima ground zero site available in Atomic Journeys.
Images from Hiroshima and Nagasaki are available in the book How to Photograph an Atomic Bomb (Hard Cover & Soft Cover) or the IPAD version.