The atomic bombing of Nagasaki

At 11.02 a.m. Japanese time on 9 August 1945 the second atomic bomb ever used against people exploded over the valley of the Urakami river in the northern part of Nagasaki. It was dropped by the B-29 bomber Bockscar, flown by Major Charles Sweeney. It was an implosion-type plutonium bomb called “Fat Man” – the same kind of device that had been tested three weeks earlier in the New Mexico desert. Three days before, another bomb had destroyed Hiroshima, and less than eleven hours before the raid on Nagasaki the forces of the Soviet Union, which had declared war on Japan the previous evening, had entered Manchuria.

Nagasaki was not the primary target of the mission. The aircraft was heading for Kokura and reached Nagasaki only after the first target, shrouded in smoke and cloud, had to be abandoned and there was barely enough fuel left in the tanks to reach the nearest airfield. Nor did the bomb fall where it was aimed – it exploded some three kilometres from the intended aiming point, over the industrial district and Catholic suburb of Urakami. According to the most frequently cited estimates, between about 40,000 and about 74,000 people had died by the end of 1945, the overwhelming majority of them civilians.

The city and the decision

Nagasaki, a port on the west coast of the island of Kyushu, was the Japanese city that had been open to the world for longest. From the 16th century Portuguese ships called there and missionaries worked in the city, and in the era of national seclusion the Dutch trading post on the artificial islet of Dejima was Japan’s only window on Europe. In the Urakami valley communities of Christians survived in hiding for more than two centuries and were still being persecuted at the beginning of the Meiji era; after the ban on their faith was lifted, they built a cathedral in Urakami, one of the largest Christian churches in Asia. In the 20th century Nagasaki became above all a centre of the Mitsubishi concern: its shipyard had built, among others, the battleship Musashi, sunk in the autumn of 1944 at Leyte Gulf, and according to post-war American studies its steelworks, arms factory and electrical plants employed some 90 per cent of the city’s industrial workers.

The city had been bombed before. In August 1944 it was attacked by B-29s flying from airfields in China, on the same night that other aircraft struck Palembang, and on 1 August 1945 high-explosive bombs fell on it, hitting, among other things, the Mitsubishi shipyard and steelworks. It had, however, escaped the great incendiary raids that since March had been reducing Japan’s cities to ashes: lying in narrow valleys between hills, it was hard to pick out on radar screens at night. It was added to the list of atomic targets late, when Kyoto was struck off.

The order of 25 July, signed in Washington by General Thomas Handy on behalf of the Chief of Staff and addressed to the commander of the Strategic Air Forces in the Pacific, Carl Spaatz, directed that the “first special bomb” be dropped after 3 August, as soon as the weather allowed visual bombing, on one of four cities: Hiroshima, Kokura, Niigata or Nagasaki. Further bombs were to be used “as soon as made ready”. No separate presidential decision was taken on the second attack – historians point out that it followed from the same order, and that in practice its timing was determined by the readiness of the weapon and the weather forecasts.

On Tinian, captured by the Americans in the summer of 1944, further Fat Man bombs were being assembled from parts delivered by air. The bomb, weighing about 4.7 tonnes and one and a half metres in diameter, with a core containing some 6.2 kilograms of plutonium, was initially to be dropped on 11 August. Because the meteorologists were forecasting five days of bad weather over Japan, Colonel Paul Tibbets, commander of the 509th Composite Group, who had been entrusted with setting the date, brought the mission forward by two days.

The flight of Bockscar

The mission went wrong from the start – one of the aircrew later said that if “everything worked” at Hiroshima, over Nagasaki “everything went wrong”. Sweeney, commander of the 393rd Bombardment Squadron, normally flew The Great Artiste, but that aircraft carried measuring instruments that could not be moved in a few hours. The aircraft were therefore swapped: Sweeney and his crew flew Bockscar, the aircraft of Captain Frederick Bock, whose name gave the bomber its nickname, while Bock took The Great Artiste with the instruments. Before take-off the flight engineer reported that the fuel pump in the reserve tank was not working: some 2,400 litres of petrol would have to be carried to Japan and back without any way of using them. Tibbets and Sweeney decided that replacing the pump or transferring the armed bomb to another aircraft would take too long and be too risky.

Bockscar took off from Tinian at 3.47 a.m. local time (2.47 a.m. Japanese time). On board were, among others, the co-pilot Charles Donald Albury, the bombardier Captain Kermit Beahan, the officer responsible for the bomb – Commander Frederick Ashworth of the US Navy – and Lieutenant Jacob Beser, a radar specialist and the only man to fly on both atomic missions. Two weather reconnaissance aircraft (one of them the Enola Gay) had taken off an hour before them, and Sweeney’s formation included The Great Artiste and the camera aircraft Big Stink, flown by Major James Hopkins. Aboard the latter, as observers for the British government, were the RAF bomber pilot Leonard Cheshire and the physicist William Penney. On The Great Artiste flew William L. Laurence of the New York Times, the only journalist admitted to the project.

Over the island of Yakushima, where the aircraft were to rendezvous, Big Stink failed to appear – according to Cheshire, it was circling at the wrong altitude. Although his instructions allowed him to wait fifteen minutes, Sweeney circled for about forty minutes and then, after conferring with Ashworth, set off with The Great Artiste for Kokura – a city with a large army arsenal, now part of Kitakyushu. The delay proved fatal. The reconnaissance aircraft had earlier reported good visibility, but now cloud and smoke from fires in neighbouring Yawata, bombed the previous day by more than two hundred B-29s, hung over Kokura; according to some accounts the Yawata steelworks was deliberately laying a smokescreen. The order required visual bombing. Over nearly fifty minutes the crew made three runs on the target, and each time Beahan could not see the aiming point. Anti-aircraft fire was getting closer, and Beser could hear increasing traffic on the Japanese fighter-control frequencies.

So little fuel was left that a return to Tinian, or even a landing on Iwo Jima, was out of the question; the only possible airfield was Okinawa, captured by the Americans six weeks earlier. Sweeney turned for the secondary target – Nagasaki. Ashworth agreed, contrary to orders, that if the target was cloud-covered they would bomb by radar rather than drop the bomb into the sea. In Nagasaki an air-raid alert had been sounded at 7.50 a.m. and lifted at 8.30; when two B-29s appeared over the city at about 10.53, it was not sounded again – evidently they were taken for reconnaissance aircraft.

11.02 a.m.

At 11.00 The Great Artiste dropped three canisters of measuring instruments by parachute. Attached to them was an unsigned letter from Los Alamos physicists, including Luis Alvarez, to the Japanese physicist Ryōkichi Sagane, whom they knew from Berkeley – urging him to persuade his country’s leaders to end the war before more bombs fell. The military found the letter, but its addressee received it only after the surrender.

A minute later a gap opened in the cloud and Beahan caught sight of the city. The bomb was released at 11.01; after falling for 47 seconds it exploded at a height of about 500 metres over the Urakami valley, roughly halfway between the Mitsubishi steelworks and arms factory to the south and the armaments works to the north – almost three kilometres north-west of the planned aiming point in the city centre. According to American measurements and later analyses, the yield was about 21 kilotons of TNT (with an uncertainty of around two kilotons), more than at Hiroshima, where the uranium bomb is estimated at about 15 kilotons.

Despite the greater yield, the destruction was less than at Hiroshima. Hiroshima lay on a flat river delta, whereas Nagasaki lies in several valleys separated by hills. The blast and heat burned out the Urakami valley, but a ridge of hills largely shielded the city centre, the port and the older districts by the bay. Had the bomb fallen where it was aimed, the damage to hospitals, public offices and the densely built centre would – in the judgement of American experts after the war – have been far greater. Within a radius of about 1.6 kilometres of ground zero almost everything was destroyed; fires engulfed the northern part of the city, but – unlike at Hiroshima – no firestorm developed. About twenty minutes after the explosion “black rain” carrying radioactive dust fell from the cloud over the hills.

Bockscar circled the city, photographed the mushroom cloud and headed for Okinawa. It landed at Yontan airfield unannounced, on its last drops of fuel, firing off all its signal flares because the control tower was not answering; one engine cut out on the approach. Big Stink, which had seen the explosion from some 160 kilometres away, flew closer to observe the cloud.

The Urakami valley

At the time of the attack, according to post-war American estimates, some 260,000 people were in Nagasaki: residents, evacuees from other cities, about 9,000 soldiers, well over ten thousand Koreans, including several thousand conscripted labourers, several hundred Chinese forced labourers and several hundred Allied prisoners of war. Most of the victims were factory workers, schoolchildren mobilised for factory work, and women and children in the wooden houses that had been packed into the valley without any plan.

Estimates of the number killed vary. The Manhattan Project report of 1946 gave about 39,000 killed and 25,000 injured, and a joint American–Japanese commission of 1951 gave 39,214 killed. The Nagasaki authorities, who gathered data on the dead in the following years, put the number killed by the end of 1945 at 73,884, with 74,909 injured. The Radiation Effects Research Foundation (RERF), a joint Japanese–American body, now estimates that of the roughly 250,000–270,000 people present in the city, between 60,000 and 80,000 had died by the end of the year. Some were killed at the moment of the explosion, some in the fires and under the rubble, and many in the following weeks and months from wounds, burns and radiation sickness.

The Mitsubishi works that were meant to be the target of the attack were largely destroyed. According to data collected after the war, some 6,200 of the 7,500 employees were killed in the arms factory alone. The valley was also home to the Mitsubishi torpedo factory, which – as is often recalled – had produced the aerial torpedoes used in the attack on Pearl Harbor.

About five hundred metres from ground zero stood Urakami Cathedral, built from 1895 by the descendants of the hidden Christians on the land where they had once been forced to trample on holy images. Ahead of the Feast of the Assumption on 15 August, the faithful were making their confessions there; everyone present was killed beneath the collapsing walls. According to figures from the Archdiocese of Nagasaki, often cited in the literature, some 8,500 of Urakami’s roughly 12,000 Catholics were killed. Takashi Nagai, a radiologist at the Medical College hospital and a Catholic, who was injured in the explosion and whose wife was killed at home, organised help for the wounded together with the surviving staff; his later memoir The Bells of Nagasaki became one of the best-known books in Japan about the attack.

Prisoners of war were also among the dead. Fukuoka camp no. 14 in Nagasaki, situated, according to researchers into the fate of prisoners, about 1.7 kilometres from ground zero, held Dutch, Australian, British and American prisoners, among others. At least eight prisoners were killed – an RAF corporal and seven Dutchmen – and according to some sources as many as thirteen.

Tokyo on the same day

In Tokyo 9 August began with the news from Manchuria: just after midnight Tokyo time the Red Army had crossed the border, and the hope that Moscow would mediate in negotiations with the Allies had proved an illusion. Before eleven o’clock the Supreme Council for the Direction of the War, the so-called Big Six, met: Prime Minister Kantarō Suzuki, Foreign Minister Shigenori Tōgō, War Minister Korechika Anami, Navy Minister Mitsumasa Yonai and the two chiefs of staff – General Yoshijirō Umezu and Admiral Soemu Toyoda. According to most accounts, news of the second bomb arrived during the meeting.

It did not change the balance of forces. Tōgō and Yonai, and, hesitantly, Suzuki too, were ready to accept the Potsdam Declaration with a single reservation – the preservation of the Emperor’s position. Anami, Umezu and Toyoda demanded three further conditions: that the armed forces disarm themselves, that any war criminals be tried by the Japanese, and that occupation of the country be prevented or limited. Anami admitted that victory was unlikely, but argued that the army could still inflict losses on the invader that would make it possible to negotiate better terms.

In the afternoon, from 2.30 p.m., and then again from 6 to 10 p.m., the full cabinet met. Cabinet decisions had to be unanimous, and the majority of ministers, although they leaned towards Tōgō’s position, could not overcome the War Minister’s resistance. Meanwhile Suzuki conferred with the Lord Keeper of the Privy Seal, Kōichi Kido, who indicated that the Emperor would agree to convene a conference in his presence and would support surrender on condition that the imperial system was preserved. The Imperial Conference began at 11.50 p.m. in the air-raid shelter beneath the palace library. After midnight, when both sides had restated their arguments, Suzuki asked Hirohito to decide. The Emperor came out in favour of accepting the declaration with a single reservation, and on the morning of 10 August Tokyo sent its offer to the Allies through Switzerland and Sweden.

Washington and the third bomb

On the evening of 9 August Harry Truman gave a radio report on the Potsdam Conference. In it he said: “The world will note that the first atomic bomb was dropped on Hiroshima, a military base.” He announced that the United States would go on using it until Japan’s power to make war was destroyed. The next day, however, when the Japanese offer arrived, the President changed the procedure followed until then. According to the diary of the Secretary of Commerce, Henry Wallace, Truman told the cabinet on 10 August that he had given orders to stop the atomic attacks, because the thought of killing another hundred thousand people was too horrible. That day General Leslie Groves reported to the Army Chief of Staff that the next bomb would be ready for use in the first good weather after 17 or 18 August; from then on its use required the President’s express authorisation. A third bomb was never dropped.

What followed

Japan’s offer of 10 August did not end the war at once. The Allies replied evasively that the authority of the Emperor and the government would be subject to the Supreme Commander of the Allied Powers; in Tokyo the dispute between the diplomats and the military flared up again, and on 14 August Hirohito had once more to settle it in person. In the broadcast recorded that day and transmitted on 15 August, the Emperor justified ending the war partly on the grounds that the enemy had used “a new and most cruel bomb”. At the same time – as historians point out – in the rescript to the armed forces issued two days later he named the Soviet Union’s entry into the war as the chief reason for surrender. The debate over which did more to bring about the surrender – the bombs or the Soviet attack on Manchuria – continues to this day.

The photographs taken among the ruins on 10 August by the army photographer Yōsuke Yamahata appeared in the Japanese press in August, but after the Americans arrived the occupation authorities subjected material on the effects of the bombs to censorship, which lasted until 1952. The survivors, known as hibakusha, struggled for years with radiation sickness and with exclusion; only in 1957 were they given statutory medical care. The best known of them became Tsutomu Yamaguchi, a Mitsubishi shipyard engineer who was in Hiroshima on business on 6 August, returned home to Nagasaki and survived both explosions – the only person officially recognised by the state as a victim of both attacks.

Urakami Cathedral was rebuilt in 1958–1959; fragments of its walls were moved to the nearby Peace Park, where a statue by Seibō Kitamura was erected in 1955. Every year at 11.02 a.m. on 9 August the city honours the victims with a minute’s silence.

The two attacks have divided historians since 1945. Supporters of the decision, led by the Secretary of War, Henry Stimson, and his much-discussed article of 1947, argued that the bombs shortened the war and spared the casualties of an invasion of Japan and of continued blockade and bombing. Critics – among them a number of American historians – maintain that Japan was close to surrender and that the second attack, carried out only three days after the first, before Tokyo had been able to assess the effects of Hiroshima and of the Soviet entry into the war, is particularly hard to justify. Other scholars reply that even after Nagasaki Japan’s leaders remained divided and that only the Emperor’s unprecedented intervention broke the deadlock. One thing is certain: since 9 August 1945 nuclear weapons have not been used in any war. Nagasaki remains the last city on which one was dropped, and the attacks on Hiroshima and Nagasaki the only combat use of such weapons in history.