Atomic Bombing of Nagasaki (1945): Fat Man and Its Victims

The atomic bombing of Nagasaki on 9 August 1945 was the second, and so far the last, use of a nuclear weapon in war. Three days after Hiroshima, an American B-29 named Bockscar dropped a plutonium bomb called Fat Man on the Japanese port city of Nagasaki, devastating the Urakami valley in the north of the city.

The bomb killed an estimated 40,000 to 80,000 people by the end of 1945. The attack came on the same day that the Soviet Union invaded Manchuria, and within a week Japan had announced its surrender, ending the Second World War.

Background

The Manhattan Project had developed two kinds of atomic bomb. One used uranium-235 in a relatively simple gun-type design; the other used plutonium in a more complex implosion design, in which explosives squeezed a plutonium core until it went critical. The implosion design was the one tested at Trinity in New Mexico on 16 July 1945.

Nagasaki itself had a long and unusual history. Founded as a port for Portuguese traders in 1571, it became Japan’s main window on the outside world during the centuries of restricted foreign contact, when Dutch merchants were confined to the artificial island of Dejima in its harbour. By 1945 it was a major shipbuilding and industrial centre dominated by Mitsubishi works, and it had been bombed only a few times before.

After the atomic bombing of Hiroshima on 6 August, the Japanese government had not yet responded to the Allied demand for surrender. American commanders on Tinian had standing orders to use further bombs as they became ready. Because bad weather was forecast from 11 August, the second mission was brought forward from 11 to 9 August.

The mission

Bockscar, normally flown by Captain Frederick Bock, was piloted on this mission by Major Charles Sweeney, whose own aircraft, The Great Artiste, carried the measuring instruments, as it had over Hiroshima. Navy Commander Frederick Ashworth served as weaponeer and Captain Kermit Beahan as bombardier. Bockscar took off from Tinian before dawn on 9 August 1945.

The bomb it carried, Fat Man, was a bulky, rounded weapon about 3.3 metres long and 1.5 metres wide, weighing roughly 4,670 kg (10,300 lb). Its core contained about 6 kg of plutonium. Unlike the Hiroshima bomb, its nuclear components could not be assembled in flight, so it was loaded fully assembled, and a crash on take-off risked a disaster on Tinian.

Problems began early. A fuel pump failure meant that hundreds of gallons of fuel in a reserve tank could not be used. At the rendezvous point over the island of Yakushima, the photographic aircraft failed to join the formation, and Sweeney waited about 40 minutes before going on.

The primary target was Kokura, home to one of Japan’s largest arsenals. When Bockscar arrived, the city was obscured by haze and smoke, partly from a conventional air raid on nearby Yawata the previous day. The crew made three bomb runs without seeing the aiming point, while anti-aircraft fire grew heavier and Japanese fighters were reported climbing towards them. With fuel running low, Sweeney turned to the secondary target, Nagasaki.

The bombing

Nagasaki, too, was largely covered by cloud. At the last moment Beahan found a gap in the clouds and released the bomb visually. Fat Man exploded at 11:02 am at a height of about 500 metres over the Urakami valley, roughly 2–3 km north-west of the planned aiming point in the city centre.

The explosion released energy equivalent to about 21 kilotons of TNT, considerably more than the Hiroshima bomb. Because the city’s steep hills shielded parts of it from the blast, the area destroyed, around 6.7 square kilometres, was smaller than at Hiroshima, and the older harbour district and city centre were less badly damaged.

The Urakami valley, however, was almost completely destroyed. The bomb exploded between two large Mitsubishi factories, the steel and arms works and a torpedo plant, both of which were wrecked. Schools, hospitals, a prison and dense residential districts nearby were flattened and burned.

Nagasaki Medical College, close to the hypocentre, was destroyed, and many of its staff and students were killed. Survivors fled to the hills or to the river, and fires burned through the afternoon and night. Relief trains carried some of the injured to nearby towns, but medical help was overwhelmed for weeks.

Short of fuel, Bockscar could not return to Tinian and made an emergency landing at Yontan airfield on Okinawa with almost empty tanks.

The victims

Nagasaki had a population of roughly 240,000–260,000 people at the time. Estimates of the number killed by the end of 1945 range from about 40,000 to 80,000, with tens of thousands more injured. As at Hiroshima, many who survived the blast died in the following weeks from burns and radiation sickness.

The dead included Japanese civilians and workers, mobilised students, Korean labourers and a small number of Allied prisoners of war held at a camp in the city. The Urakami district was the historic heart of Japan’s Catholic community, whose ancestors had kept their faith in secret during centuries of persecution. Urakami Cathedral, then the largest church in East Asia, stood about 500 metres from the hypocentre and was reduced to ruins, killing the worshippers inside. Thousands of the area’s Catholics died.

Key people

Charles Sweeney commanded the mission and later defended it in his memoirs. Kermit Beahan, the bombardier, released the bomb through a gap in the clouds. Frederick Ashworth was the senior officer responsible for the weapon on board.

Takashi Nagai, a Catholic radiologist at Nagasaki Medical College, lost his wife in the bombing and was himself injured. Despite suffering from leukaemia, he treated victims and wrote books including The Bells of Nagasaki, which made him one of the best-known survivors. He died in 1951.

Tsutomu Yamaguchi, an engineer from Nagasaki who was on a business trip to Hiroshima on 6 August, returned home and was exposed to the second bomb as well. In 2009 he became the only person officially recognised by the Japanese government as a survivor of both bombings. He died in 2010.

Yosuke Yamahata, a Japanese army photographer, entered the city on 10 August, the day after the bombing, and took more than a hundred photographs of the devastation and the victims. His pictures are among the most important visual records of the immediate aftermath of a nuclear attack.

Japan’s surrender

When news of the Nagasaki bomb arrived, Japan’s Supreme Council for the Direction of the War was already meeting in Tokyo to discuss the Soviet declaration of war and the Soviet invasion of Manchuria, which had begun shortly after midnight. The council and the cabinet remained deadlocked between accepting the Potsdam Declaration with a single condition, the preservation of the emperor’s position, and holding out for further conditions.

Late that night, at an imperial conference, Emperor Hirohito broke the deadlock and favoured acceptance. Japan sent its conditional acceptance on 10 August. After further exchanges and a failed coup attempt by army officers, the emperor’s recorded broadcast announced the surrender of Japan on 15 August 1945.

On 10 August President Truman ordered that no further atomic bombs be used without his express authority. A third bomb could have been ready later in August, but it was never used.

Debate and legacy

The Nagasaki bombing is debated even more sharply than Hiroshima. Some historians argue that the second bomb was unnecessary because Japan had not had time to respond to the first, and that the Soviet entry into the war was already pushing it towards surrender. Others hold that the second bomb showed Japan’s leaders that the United States could continue such attacks, strengthening the case for surrender.

Nagasaki was rebuilt after the war. The Nagasaki Peace Park, near the hypocentre, contains the Peace Statue by the sculptor Seibo Kitamura, completed in 1955. Urakami Cathedral was rebuilt in 1959, and the Nagasaki Atomic Bomb Museum opened in its current form in 1996. Every year on 9 August, a memorial ceremony is held in the city and a moment of silence is observed at 11:02 am.

The mayor of Nagasaki reads a Peace Declaration at the ceremony each year, and the city has sought to preserve the ruins and testimonies of the bombing. Remnants of the old Urakami Cathedral, including a wall and a damaged bell tower, can still be seen, some at the cathedral and some in the Peace Park area.

The city’s survivors have campaigned for the abolition of nuclear weapons, often expressing the wish that Nagasaki remain the last place ever to suffer a nuclear attack.

Timeline

• 1945, 16 July: The plutonium implosion design is tested at Trinity.
• 1945, 6 August: The first atomic bomb destroys most of Hiroshima.
• 1945, 9 August, shortly after midnight: Soviet forces invade Manchuria.
• 1945, 9 August, before dawn: Bockscar takes off from Tinian.
• 1945, 9 August, morning: Clouds and smoke prevent bombing at Kokura.
• 1945, 9 August, 11:02 am: Fat Man explodes over Nagasaki.
• 1945, 10 August: Japan offers to surrender on condition that the emperor’s position is preserved.
• 1945, 15 August: Emperor Hirohito’s broadcast announces Japan’s surrender.

Why it matters

Nagasaki was the last nuclear attack in history. Together with Hiroshima, it showed the world the devastating human cost of atomic weapons and helped end the Second World War, while raising moral and strategic questions that still shape debates about nuclear arms today.