This Day in History — The Atomic Bombing of Nagasaki
On this day in 1945
On August 9, 1945, Fat Man detonated over Nagasaki at 11:02 a.m. — three days after Hiroshima, because clouds over Kokura had saved that city instead.
The Off-Key Bard stands in silence once again. Only three days had passed since Hiroshima, and humanity was about to witness the destructive power of a nuclear weapon for a second time…
"Once might have been unimaginable. Twice proved that the world had changed forever."
On this day in 1945, the United States dropped a second atomic bomb on Japan. The plutonium-implosion device codenamed Fat Man detonated at 11:02 a.m. over the Urakami Valley in Nagasaki, at an altitude of approximately 500 meters — with a yield of roughly 21 kilotons, about 40 percent more powerful than the bomb that had destroyed Hiroshima three days earlier.
Nagasaki had not been the original target that morning.
Bockscar — the B-29 piloted by Major Charles Sweeney — had been assigned to strike Kokura, a city on the northern coast of Kyushu housing one of Japan's largest military arsenals. Bockscar arrived over Kokura on schedule and circled for 45 minutes. Smoke and haze, possibly from firebombing of a neighboring city, obscured the target. Visual confirmation was required; without it, the bomb could not be released. After three failed passes, with fuel running critically low, Sweeney turned south toward the secondary target. Kokura was spared by clouds. Nagasaki was not.
Over Nagasaki, clouds again obscured the city. Sweeney prepared to abort. At the last moment, a gap opened over the Urakami Valley — nearly two miles north of the intended aim point over the city center. Bombardier Captain Kermit Beahan had seconds to decide. He released the bomb.
The Urakami Valley's surrounding hills partially contained the blast, limiting the destruction compared to what had happened across Hiroshima's flat river delta. But the shockwave swept directly down the valley, destroying schools, hospitals, factories, and Urakami Cathedral — the largest Christian church in East Asia, standing approximately 500 meters from the hypocenter. Between 40,000 and 74,000 people were killed; estimates vary significantly across sources, with American government postwar figures at the lower end and Japanese estimates higher. By the end of 1945, the toll had risen to approximately 70,000–80,000 as radiation sickness and burn injuries claimed thousands more — the vast majority civilians.
The warning leaflets that had been prepared to inform Nagasaki's population of the possible coming attack were delivered to the city the day after the bomb fell, due to poor coordination between military units. They drifted down over the ruins on August 10.
Three days after Nagasaki, the Soviet Union formally declared war on Japan and invaded Manchuria. On August 15, Emperor Hirohito announced Japan's surrender. The formal ceremony took place on September 2, 1945.
Historians continue to discuss the complex intersection of factors that ended the Pacific War — the conventional firebombing campaign, the Allied naval blockade, the Soviet entry, and the atomic bombings — and the question of whether the bombings were necessary to achieve surrender without an invasion remains one of the most debated in twentieth-century history. Both sides of that argument are serious, and both remain active in the scholarly literature.
One fact endures above all others: Nagasaki remains the last city in human history to suffer a nuclear attack.
"A second flash, a second scar,
The consequences traveled far…
And from the ruins came the plea,
That no third city ever see."
History does not remember August 9 simply as one of the final chapters of World War II. It remembers it as a solemn, permanent warning — and as the last day the threshold between a world with nuclear weapons and a world that has used them in war was crossed.