The Osaka raid of 15 June

On the morning of 15 June 1945 several hundred American B-29 Superfortress bombers appeared over Osaka, Japan’s second-largest city, for the third time in two weeks. According to American figures, XXI Bomber Command dispatched 511 aircraft that day, of which 444 dropped more than 3,100 tons of bombs, mostly incendiaries, on Osaka and neighbouring Amagasaki. About 4.9 km² of Osaka’s built-up area and 1.5 km² of Amagasaki’s were burned out. It was the last of the great raids on Japan’s largest cities – after it, General Curtis LeMay’s command considered the first phase of the incendiary campaign complete and turned its bombers against medium-sized and small cities.

The statement found in war chronologies that on 15 June “Osaka is heavily bombed” is accurate. It is worth adding only that this was one of a whole series of raids on the city and that, in terms of the area destroyed, it was not the heaviest – the raids of March and of 1 June caused greater damage.

Osaka in the incendiary campaign

Before the war Osaka had more than 3 million inhabitants and was the largest industrial centre of western Japan: a port, a centre of the textile, metal and chemical industries, and the home of one of the army’s largest armament works – the Osaka Arsenal, which stood right next to Osaka Castle. As in other Japanese cities, industrial production here was dispersed among thousands of small workshops in residential districts built largely of wood. It was this pattern that American planners in 1943–1944 regarded as justifying incendiary attacks on entire urban areas.

B-29s first burned Osaka on the night of 13–14 March 1945, as part of the March series of raids that began with Tokyo and also took in Nagoya and Kobe. According to American figures, 274 bombers destroyed about 21 km² of the city, and according to Japanese figures nearly 4,000 people were killed. Then, through April and early May, a large part of LeMay’s force supported the fighting on Okinawa by bombing the airfields on Kyushu from which the kamikaze pilots took off.

In mid-May the offensive against the great cities resumed. The B-29s struck Nagoya, Tokyo twice and Yokohama, and in June it was the turn of Osaka and Kobe. By then the command had five bombardment wings in the Marianas, and since March the bombers had been able to make emergency landings on Iwo Jima, from which P-51 Mustang escort fighters also flew.

The June raids on Osaka

On 1 June 1945, in daylight, 521 bombers took off against Osaka with an escort of 148 fighters. On the way to Japan the fighters ran into dense cloud and, according to American figures, 27 of them were lost in collisions and accidents before even reaching the target. Even so, 458 bombers dropped their loads on the city, destroying about 8.2 km² of buildings, above all the port districts along the Aji River. According to figures cited in the literature, 3,960 people were killed. Mustangs also appeared over Osaka for the first time, strafing ground targets.

On 5 June 473 B-29s bombed Kobe, losing 11 aircraft, and on 7 June 409 bombers returned to Osaka. This time, alongside incendiaries, they also dropped heavy high-explosive bombs aimed at the arsenal. According to Japanese studies, many of them fell far from the target, on residential districts; a direct hit on the Nagara bridge, under which several hundred people had taken shelter, together with strafing, killed about 400 people according to these accounts. Another 5.7 km² of the city burned, and the Americans lost no bombers.

15 June: bombing through cloud

The raid of 15 June, Mission No. 203 in American records, was a joint undertaking of four bombardment wings – the 58th, 73rd, 313th and 314th. Five aiming points were designated: two in Osaka (around the Tsuruhashi and Tennōji stations and in the Nishiyodogawa district) and the rest in Amagasaki, an industrial city in Hyōgo Prefecture adjoining Osaka on the west. According to Japanese figures, the bombing lasted from 8.44 to 10.55 a.m. local time, more than two hours.

Thick cloud lay over the target, so the crews bombed by radar. About 100 P-51 fighters that were to have covered the mission turned back because of the bad weather. Japanese defences inflicted no serious losses on the bombers: according to American figures, two B-29s crashed in accidents near the bases in the Marianas (one on take-off, the other in the sea near Guam), and 43 aircraft landed on Iwo Jima on the way back. In addition, 25 bombers that did not reach the primary target attacked targets of opportunity.

Bombing through cloud was less accurate than low-level night raids in good visibility, so the damage was spread more widely. Not only Osaka and Amagasaki suffered, but also Sakai, Fuse (today part of Higashiōsaka), Toyonaka and Moriguchi. According to Japanese studies, 477 people were killed – far fewer than on 1 June. This was partly because, after the earlier raids, the central districts had already been largely burned out and depopulated, and hundreds of thousands of residents had left the city. According to some tallies, a total of about 300,000 houses in Osaka were destroyed in the four June raids; these figures, however, are uncertain.

The end of the first phase of the campaign

For the American command, the raid of 15 June closed the first stage of the incendiary offensive. Between March and mid-June the B-29s had largely destroyed Japan’s six largest cities – Tokyo, Osaka, Nagoya, Yokohama, Kobe and Kawasaki. According to American figures, more than 270 km² of built-up area and about 1.5 million houses burned in them, and in Tokyo, Osaka and Nagoya alone the area destroyed was greater than in all the German cities bombed by the Americans and British combined. Historians estimate the number killed in these cities between March and June, depending on the source, at 112,000–127,000, and millions of people lost their homes.

On the target list drawn up in the following weeks – which, according to Japanese studies, covered some 180 cities ranked by population – Osaka was marked as already destroyed. As early as the night of 17–18 June, 477 bombers struck four medium-sized cities: Hamamatsu, Kagoshima, Ōmuta and Yokkaichi. These cities were almost undefended, and each was attacked by a single bombardment wing using the same method as had earlier been used against the great cities. This pattern – incendiary raids on several smaller cities at once and, in good weather, precision attacks on selected industrial plants – remained in force until the end of the war.

Osaka until August 1945

Osaka did not, however, cease to be a target. The subsequent raids, on 26 June, 24 July and 14 August, were aimed chiefly at the Sumitomo works and the arsenal, and on the night of 9–10 July B-29s burned neighbouring Sakai, where according to Japanese figures more than 1,300 people were killed. The arsenal, which for many months had come through the raids without major damage, was destroyed only on 14 August, the day before Japan’s surrender was announced. Heavy bombs also struck the castle grounds – several historic turrets and gates burned, though the main keep, rebuilt in reinforced concrete in 1931, survived – and the nearby Kyōbashi station, where many travellers were killed. The total number of civilian victims of the raids on Osaka is estimated at more than 10,000.

Significance

The raid of 15 June was not the peak of the bombing of Osaka, but it marked a turning point in the campaign as a whole. By mid-June the Americans had achieved the goal planners had set themselves since 1943: they had largely destroyed the industrial centres of Japan’s largest cities, breaking up the network of small workshops on which armaments production depended. The offensive moved on to medium-sized and small cities, and its cost was borne above all by the civilian population. The destruction of the spring and summer of 1945 showed many Japanese that the army and navy could no longer defend the home islands, although the country’s leaders still rejected the idea of surrender. Japan’s great cities lay in ruins weeks before the atomic bomb was used – and that is the context in which the last decisions of the Pacific war were taken in the summer of 1945.