Analysis: The Atomic Bombings of Hiroshima and Nagasaki: The Selection of the Target

Date: June 19, 1946

Author: US Army

Genre: report

Summary Overview

In August 1945, the US military used two atomic bombs against the Japanese cities of Hiroshima and Nagasaki. Intended to show Allied military dominance and the futility of a continued war effort by the Japanese, the bombings leveled large parts of the cities and killed more than one hundred thousand people, military and civilian alike. By this time, US air raids had been dropping firebombs throughout much of Japan for months, and intense ground fighting was going on in parts of the Pacific. US leaders realized that defeating Japan would require immense human and economic resources from countries already exhausted by years of war. They hoped to use the devastating force of newly developed atomic weapons to force a rapid end to the war and avoid a lengthy invasion of Japan. Part of the process for achieving this aim, as described in this excerpt, was finding bombing targets that were both strategic and accessible.

Defining Moment

World War II began in Europe in 1939, but the United States resisted joining the conflict until the Japanese air attack on the US naval base at Pearl Harbor, Hawaii, in December 1941. Although the United States focused many of its resources during its early period of involvement on a strategy to achieve victory in Europe, US sentiment against the Japanese was extremely high throughout the war due to the attack on Pearl Harbor. Fighting against Japanese forces in the Pacific was extremely intense and quite bloody. Beginning in 1942, US troops sought to resist the Japanese in the Philippines, a strategic island nation in the Pacific. But they were largely unsuccessful. In one instance, harsh Japanese treatment of thousands of US prisoners of war in the Philippines resulted in so many casualties that it became known as the Bataan Death March. Japan's aggressive strategies and willingness to employ extreme tactics made it difficult for the United States and its allies to gain a foothold in the region.

As the war in Europe began to turn decisively in favor of the Allies, however, the United States began to recommit to the Pacific theater. US forces began to capture small islands such as Guam from Japanese control in 1944. Troops under General Douglas MacArthur managed to take back control of much of the Philippines from the Japanese in early 1945. From these sites across the Pacific, the US military was able to conduct a series of air raids against mainland Japanese cities. Air raids had been used to great effect by both sides in the war in Europe, and the US campaigns echoed some of the strategies of these earlier efforts; flyers varied tactics and targets in order to surprise the enemy and to cause the most damage possible and had no qualms about using weapons that affected both military and civilian installations. One common air bombing target, for example, were military complexes surrounded by workers' homes. Leaders believed that targets of this nature damaged the Japanese capability to wage war by both eliminating industrial prowess and weakening the morale of the people who were sustaining the war effort. Airplanes equipped with firebombs were particularly devastating. In a single US firebomb attack on Tokyo in March 1945, called Operation Meetinghouse, some one hundred thousand civilians perished.

By the time Allied scientists working on the Manhattan Project perfected the atomic bomb in July 1945, a precedent for using weapons against both military and civilian targets in Japan was already set. Political and military leaders also wanted to achieve a quick victory to stop human and economic resource depletion and to bolster US morale. President Harry S. Truman authorized the atomic bombing of Hiroshima, and this first bombing took place on August 6.

Author Biography

Published by the US Army in the June of 1946, this analysis of the bombings of Hiroshima and Nagasaki drew on research and commentary by numerous military and scientific groups, including the Special Manhattan Engineer District Investigating Group, the US Strategic Bombing Survey, the British Mission to Japan, and the Joint Atomic Bomb Investigating Group. In May 1945, US secretary of war Henry L. Stimson had organized a special committee to study possible applications of the atomic bomb and make recommendations for its usage. Known as the Interim Committee, this group included representatives from the Truman administration, branches of the military, and the Manhattan Project; some of the atomic bombs' main developers, including J. Robert Oppenheimer and Enrico Fermi, contributed to the deliberations. The Interim Committee briefly considered advising against the use of the atomic bomb or suggesting that it be detonated away from a populated area as a demonstration of its power. These strategies were quickly rejected, however, and the committee members turned their attention to identifying ideal military targets. This excerpt from the overall US Army report focuses mostly on the recommendations made by these groups.

Document Analysis

One goal of the US Army's report on the atomic bombings of Hiroshima and Nagasaki was to address common questions about relevant strategy and effects, including the choice of targets. This section of the report briefly lays out the consideration given to the target and explains the reasoning behind the selection of Hiroshima and Nagasaki, neither of which were among Japan's most populated cities nor main government centers. Instead, factors ranging from geographic location to climate to architecture shaped the strategic decisions.

The report emphasizes that the need for extensive research and testing made the use of the nuclear weapon impracticable before August 1945. It then summarizes the considerations used to select the bombing targets. The targets had to be accessible to US airplanes carrying the weapons, for example, and located near enough to other suitable sites to allow for the mission to be adjusted should weather impede the planned bombing.

Several characteristics made both Hiroshima and Nagasaki strategically suitable. Hiroshima was untouched by US firebombs; therefore, “the effect of a single atomic bomb could be determined” there as a result. The city housed a large number of military units, and its center contained the “closely-built frame buildings” that military planners rightly estimated “would be most susceptible to damage by blast and fire.” Nagasaki was an industrial and shipping hub that had experienced only a handful of firebombing raids. Although Nagasaki was a secondary target, conditions led bombers to choose the site when the primary target, the city of Kokura, was too clouded for a visual approach.

The report closes by summarizing the constraints on the selection of sites and the timing of the raids. As it had been with the decision to bomb Nagasaki rather than Kokura, weather proved a major factor. Tokyo, as the Japanese capital and largest population center, may have seemed like the most natural strategic target. In order to address any readers who would have preferred this target to be selected for bombing, the report specifically points out that climatic records showed a long history of poor visibility likely to make a bombing there a challenge. Weather also influenced the decision to conduct the bombings in early August, as conditions in September were expected to pose greater challenges to visibility and ground weather. The report, therefore, emphasizes that the decision of when and where to bomb was influenced as much by physical factors as by political ones.

Bibliography and Additional Reading

Hersey, John. Hiroshima. New York: Knopf, 1946. Print.

Hogan, Michael J., ed. Hiroshima in History and Memory. New York: Cambridge UP, 1996. Print.

Kort, Michael. Columbia Guide to Hiroshima and the Bomb. New York: Columbia UP, 2007. Print.