B-29 raids on Japan in January 1945

On 6 January 1945 American B-29 Superfortress bombers appeared over Japan once again – this time not over the capital but over Ōmura on Kyushu, home to the Japanese navy’s aircraft works. Forty-nine aircraft of XX Bomber Command took off from the airfields around Chengdu. The forecast predicted cloud and proved right: according to the American official history of the air force (Wesley F. Craven and James L. Cate), 28 bombers dropped their bombs on Ōmura by radar, eleven attacked the secondary target at Nanjing visually, and six bombed targets of opportunity. One B-29 was lost. That same day Brigadier General Lauris Norstad, chief of staff of the Twentieth Air Force, flew into Guam and informed the commander of the bombers in the Marianas, Brigadier General Haywood Hansell, that he was being relieved.

Popular chronicles of the war state under this date that B-29s “bombed Tokyo again”. That was not the case: no raid on the capital by XXI Bomber Command from the Marianas is recorded on 6 January. In January the B-29s from the Marianas attacked Nagoya (3, 14 and 23 January), the Nakajima works at Musashino near Tokyo (9 and 27 January) and the Kawasaki works at Akashi (19 January). The date of 6 January nonetheless captures the turning point of that month well: the raids from China were coming to an end, and the command in the Marianas was the subject of a decision that would change the way the whole campaign was waged.

The end of the bombing from China

The B-29 raids from China, flown from Sichuan since June 1944, had not lived up to the hopes placed in them. Every sortie over Kyushu required many flights carrying fuel and bombs over the Himalayas, and the Japanese offensive in southern China, with Nanning taken and Kunming threatened, made supply even more difficult. Ōmura was one of the few targets where the bombers from China did serious damage – post-war analyses judged the Ōmura works to be the only target of this campaign effectively destroyed.

The last missions from Chengdu supported the American landing on Luzon: on 9, 14 and 17 January the B-29s attacked ports and airfields on Taiwan – Keelung, Chiayi and Hsinchu. The attack on Hsinchu was the last mission flown from the Chinese bases. From then on XX Bomber Command concentrated on targets in South-East Asia within reach of India, such as the Rama VI Bridge in the B-29 raid on Bangkok, and its commander, Major General Curtis LeMay, flew off to the Marianas.

The difficulties of precision bombing

General Hansell’s XXI Bomber Command had been attacking Japan from Saipan since November 1944, after the arrival of the B-29s in the Marianas and the first B-29 raids over Tokyo; at the turn of 1944 and 1945 further bomb wings were arriving on Tinian and Guam. Hansell, one of the architects of the American doctrine of daylight precision bombing, sent his bombers above all against aircraft and aero-engine plants. But he faced conditions the American air force had never encountered before. Over Japan, at bombing altitude – some 9,000–10,000 metres – blew the jet stream, at speeds of up to 200 knots and more according to the crews’ accounts. Bombers flying downwind raced over the target too fast for the bombsights to aim accurately, while those flying upwind almost stood still, exposed to anti-aircraft fire. Japan was almost constantly under cloud, and the B-29s’ engines, overstrained by the long climb with a full load, often failed; many aircraft ditched on the return leg of more than 2,000 kilometres over the ocean.

The January raids from the Marianas

The first January raid was a trial of a new method. The leadership of the Twentieth Air Force in Washington, increasingly convinced that burning Japan’s cities, built largely of wood, would be more effective than attacks on individual factories, instructed Hansell to test incendiary bombs. On 3 January 97 B-29s took off for Nagoya with a mixed load of high-explosive bombs and incendiary cluster bombs; according to the official history, 57 bombed the urban area. The fires they started, however, were quickly brought under control.

After that Hansell returned to precision attacks. On 9 January 72 bombers set out for the Nakajima aero-engine works at Musashino near Tokyo. A strong wind broke up the formations and only eighteen aircraft bombed the primary target; the rest dropped their bombs on the port and on districts of the city. Six B-29s were lost. On 14 January, of 73 bombers sent against the Mitsubishi aircraft works at Nagoya, forty dropped their bombs, and a mere four high-explosive bombs hit the works.

The best result came from the last raid Hansell planned. On 19 January 77 bombers (and three more in a diversionary attack) flew against the Kawasaki aircraft works at Akashi on the Inland Sea. In good weather 62 aircraft dropped 155 tons of high-explosive bombs and returned without loss; according to the American assessment, 38 per cent of the plant’s roofed area was seriously damaged, and production collapsed for a time. It was the first fully successful B-29 precision raid on Japan – and at the same time Hansell’s argument that his method could work when the weather allowed.

On 20 January LeMay took over command; Hansell left Guam the following day. The first raids under the new command produced results no different from the earlier ones: on 23 January, of 73 bombers sent once again against the Mitsubishi works at Nagoya, only 28 dropped their bombs, and on 27 January the attack on Musashino was frustrated by cloud and high winds – 62 B-29s bombed the port and urban districts of Tokyo instead of the factory. According to the official history, XXI Bomber Command’s losses rose in January to 5.7 per cent of the bombers that took off; in the first three months of the campaign they had averaged about 4 per cent per mission.

The defence of Japan

Japanese air defence was weak compared with Germany’s – there was a shortage of radar, of artillery capable of hitting targets at high altitude and of fighters with adequate performance – but American airmen felt it ever more keenly. The B-29s were opposed by the army’s Nakajima Ki-44, Kawasaki Ki-61 and twin-engined Kawasaki Ki-45 fighters and by the navy’s Mitsubishi J2M Raiden. Because they found it hard to climb to the bombers’ altitude and shoot them down with their guns, special detachments were formed in the units defending Tokyo whose pilots, in lightened aircraft with reduced armament, were to strike the B-29s by ramming. Some pilots managed to bail out after such an attack; for others it was a suicide attack, similar in spirit to the kamikaze attacks at sea, such as those in which kamikaze struck the carriers. The Japanese also attacked the airfields in the Marianas themselves, especially from Iwo Jima, which lay halfway and from which Japan’s defences were warned of approaching bombers.

At the end of January Imperial General Headquarters belatedly adopted a civil defence plan: firefighting was entrusted to district councils and neighbourhood groups of residents, since the professional fire brigades were short of men, a blackout from 10 p.m. was introduced, and firebreaks were created by demolishing buildings. In the face of mass incendiary raids these measures were to prove inadequate.

Hansell and LeMay

Hansell’s removal was not the result of a single unsuccessful raid. General Henry H. Arnold, commanding general of the Army Air Forces, who personally commanded the Twentieth Air Force and answered to Congress for the enormous cost of the B-29 programme, expected quick results. Hansell defended the precision bombing of factories, was sceptical of incendiary raids on cities and was – in his superiors’ view – too cautious in the face of technical and weather problems. LeMay, who in India had improved the training and maintenance of XX Bomber Command’s bombers, was regarded as a commander capable of getting more out of the B-29. According to American studies, Arnold took the decision to replace him at the end of December 1944; Norstad conveyed it to Hansell on 6 January.

LeMay at first continued his predecessor’s methods while improving maintenance and training. Only in February did he begin to try out incendiary raids on a larger scale – on Kobe on 4 February and on Tokyo on 25 February. During the night of 9–10 March 1945 more than 300 B-29s, flying low, at night and stripped of most of their defensive armament, dropped incendiary bombs on Tokyo. Flying low avoided the jet stream and saved engines and fuel, and Japanese night defences were weak. The firestorm destroyed several dozen square kilometres of the city and killed, according to various estimates, between about 80,000 and more than 100,000 people.

Place in the war

January 1945 closed the first stage of the strategic air offensive against Japan. It had become clear that the method developed over Germany – daylight precision bombing from high altitude – failed over Japan because of the weather, the distances and the wind, although the successful raid on Akashi showed that it was not useless. The change of commander opened the way to the incendiary raids, which from March to August 1945 destroyed most of Tokyo, Nagoya, Osaka, Kobe and Yokohama and dozens of smaller cities and killed hundreds of thousands of civilians. The assessment of this change – whether it was a military necessity or a crossing of the line between military targets and the civilian population – remains one of the main controversies in the history of air warfare. The campaign was brought to an end in August 1945 by the atomic bombs dropped on Hiroshima and Nagasaki by B-29s flying from Tinian.