Atomic bombing of Nagasaki, August 9, 1945

The atomic bombing of Nagasaki on August 9, 1945, brought a second atomic strike against Japan within three days, while Soviet forces entered the war in Asia. The attack killed an estimated 70,000 people. Its place in the closing days of the war is defined not only by its immense destruction but by the convergence of events: the bomb was released under an existing military directive, and Japan’s leaders were still divided when news of the strike reached them.

Strategic Context

The weapon’s existence had been kept secret even from many government officials. In June 1943, after staff investigators encountered unexplained expenditures associated with the Manhattan Project, Harry S. Truman asked Secretary of War Henry L. Stimson about the project. Stimson told him it was a highly important secret development and assured him it had a specific, unique purpose. Truman accepted that assurance without demanding further explanation. By July, however, he had learned enough to recognize the essential nature of the project.

In June 1945, the prospect of invading Japan remained an immediate problem. Truman recorded that he had to choose between invasion and bombing and blockade, calling it his hardest decision to date. At a White House meeting on June 18, General George C. Marshall presented a two-phase invasion plan beginning with Kyushu in November. Marshall said the initial phase could produce losses comparable to those on Luzon, about 31,000 in its first thirty days. The atomic bomb was not discussed at that meeting, a silence that struck Assistant Secretary of War John J. McCloy as if planning were proceeding on the assumption that the weapon did not exist.

The public terms announced at Potsdam also formed part of the immediate setting. The Potsdam Declaration promised humane treatment and said that Japan would not be enslaved as a race or destroyed as a nation. Its sole use of the phrase “unconditional surrender” applied to the armed forces, not the Japanese nation. The declaration threatened “prompt and utter destruction,” but did not explain what that phrase meant or specify the fate of Emperor Hirohito. The government in Tokyo would later accept the declaration on the understanding that the Emperor could remain sovereign.

The Second Bomb and Its Release

On August 7, Harry S. Truman returned to Washington aboard the Augusta. Japan had still offered no sign of surrender, and Henry L. Stimson and General George C. Marshall privately worried that the first bomb had failed to produce the shock they hoped for. Two days later, the news changed abruptly: a million Russian troops had crossed into Manchuria, and a second atomic bomb had been dropped on Nagasaki, a major Japanese seaport.

The weapon was a plutonium bomb nicknamed Fat Man. It had been transported from Tinian and used two days ahead of schedule because of weather conditions. Later estimates put the death toll at 70,000. The damage would have been worse had the bombardier not missed the intended target by two miles. Those figures describe a devastating attack, while also revealing how the strike’s actual effects were shaped by the bomb’s destructive force and the distance between its detonation and the target.

The bomb’s power had already been demonstrated at the Trinity test. A 220-ton steel test cylinder, set half a mile from the explosion and encased at its base in concrete, was torn from its foundations; its surrounding steel tower was twisted, ripped apart, and flattened. The test report said that the tower’s destruction suggested unshielded permanent steel and masonry buildings at that distance would have been destroyed. Nagasaki translated such technical evidence into mass civilian death.

No New Presidential Decision

No high-level meeting had been held about using the second bomb, and Truman made no additional decision before it was dropped. The operative authorization was a military directive issued on July 25 for the first bomb. Its second paragraph stated: “Additional bombs will be delivered on the above targets as soon as made ready by the project staff….” Once Fat Man was ready, it was delivered under that standing instruction.

This sequence distinguishes the second strike from a fresh presidential choice made in response to events in Japan. The book describes no new meeting at which Truman weighed Nagasaki as a separate decision, and no additional order from him. Instead, the existing directive supplied the authority under which the weapon was used. The distinction matters in understanding how a decision made earlier had continuing consequences after the immediate strategic and political circumstances changed.

Japan’s Decision and the Immediate Aftermath

On the morning Nagasaki was bombed, Japan’s Supreme Council for the Direction of the War was meeting in Prime Minister Kantaro Suzuki’s bomb shelter outside the Imperial Palace in Tokyo. The council was deadlocked. Three powerful military commanders—two generals and an admiral—argued fervently against surrender. War Minister Korechika Anami called for a final battle on Japanese soil and argued that the country should draw the American forces ashore. He framed the prospect of national destruction as a matter of honor.

News of the Nagasaki bombing brought the meeting to an end for the time being. The council reconvened that night with Hirohito in the Imperial Library. Less than twenty-four hours after Nagasaki, the Emperor decided that Japan must “bear the unbearable” and surrender. The Japanese government then agreed to accept the Potsdam Declaration on the condition that the Emperor remain sovereign. The sequence shows that the bombing arrived amid a fierce internal dispute, followed quickly by an imperial decision; it does not, by itself, establish that the bomb alone determined the outcome.

Significance

The date marks both a second nuclear attack and a moment when several pressures converged. The Soviet entry into the war, the unresolved terms surrounding the Emperor, the Japanese leadership’s resistance to surrender, and the bomb’s use under a pre-existing order all belong to the event’s immediate context. The evidence supports a precise account of the sequence, rather than a simple claim that one factor alone ended the war.

The Nagasaki strike also exposed the difference between the abstraction of military instructions and their human consequences. A directive could describe additional bombs as weapons to be delivered when ready; the result in Nagasaki was an estimated 70,000 deaths, with still greater destruction narrowly avoided by the bombardier’s two-mile miss. In the political and military story, the bomb was one instrument in the final crisis. In the city, its arrival was catastrophic.