The 'Bombing of Osaka' was part of the US 20^th Army Air Force’s strategic bombing campaign against Japan in the later stages of World War II (13 March/14 August 1945).

Osaka is the second largest city in Japan, with a 1940 population of 3,252,340 persons, and was also the most important concentration of industrial targets in the Far East. Osaka was one of Japan’s principal centres of heavy industry, noted for its shipbuilding, iron, steel and rolling stock works, as well as enterprises concerned with non-ferrous metals such as copper and aluminium. In addition, it was notable for production of aircraft propellers and propeller governors, munitions and ordnance, textiles, special steels, wires, electrical equipment, chemicals, instruments, and machines and machine tools, particularly anti-friction bearings. It was also a transportation hub and the location of Japan’s third largest port, on which much work had been done to develop its naturally shallow harbour. The city was also the centre of Japan’s railway network.

The first air raid on Osaka lasted from 23.57 to 03.25 on 23 March 1945 as 274 Boeing B-29 Superfortress four-engined heavy bombers attacked. The first wave of 43 bombers of Brigadier General Thomas S. Power’s 314^th Bombardment Wing arrived from Guam island in the Mariana islands group and bombed from an altitude of about 6,500 ft (1980 m). The first bombers dropped incendiary bombs at targets in the Minato ward, and started a firestorm. The second wave of 107 bombers of Brigadier General John H. Davies’s 313^th Bombardment Wing arrived from Tinian in the Mariana islands group and attacked the Naniwa ward. Finally, 124 bombers of Brigadier General Emmett O’Donnell’s 73^rd Bombardment Wing from Saipan in the Mariana islands group arrived and attacked the Kita and Nishi wards. This single raid killed 3,987 persons and left 678 other persons missing, and destroyed 8.1 sq miles (21 km²) of the city for the loss of just two aircraft. The destruction of Osaka was concentrated almost wholly in one area to the south-west of Osaka Castle. The US forces suffered no crew casualties during the mission. The aircraft lost were accidental crashes on take-off, but all the crew members escaped the ensuing conflagrations.

On 1 June, 521 B-29 bombers escorted by 148 North American P-51D Mustang single-engined fighters were despatched in a daylight raid against Osaka. On their way to the Japanese city, the Mustang fighters flew through thick cloud and lost 27 of their number in collisions. Nevertheless, 458 heavy bombers and 27 P-51 fighters reached the city and the following bombardment killed 3,960 Japanese and destroyed 3.15 sq miles (8.2 km²) of buildings. A force of 409 B-29 bombers attacked Osaka again on 7 June: during this attack 2.21 sq miles (5.7 km²) of buildings were burned out and the Americans suffered no losses. Osaka was bombed for the fourth time in the month on 15 June when 444 B-29 bombers destroyed 1.9 sq miles (4.9 km²) of the city and another 0.59 sq miles (1.5 km²) of nearby Amagasaki; 300,000 houses were destroyed in Osaka.

On 24 July, 625 B-29 bombers were despatched against seven targets near Nagoya and Osaka. On the night of 6/7 July Brigadier General Frank A. Armstrong’s 315^th Bombardment Wing destroyed the Maruzen oil refinery near Osaka, and three nights later it completed the destruction of the Utsube refinery.

The eighth bombing raid on Osaka took place on 14 August, just one day before the end of the war, when about 150 B-29 bombers attacked the city and dropped about 700 2,000-lb (907-kg) bombs, targeting the Japanese army’s factories in the eastern part of Osaka. Four units of these bombs were also dropped onto the Kyobashi station of the Japan national railway nearby at about 13.00, causing substantial damage to the station, which was crammed with civilians at this time. Two trains had just arrived when the bombs were dropped, and the dead comprised more than 210 dead but identifiable civilians and more than 500 who could not be identified.