Bombing of Osaka The bombing of Osaka during World War II first took place from the middle of the night on March 13 , 1945 , to the early morning of the next day . There were also bomb raids on June 6 , 7 , 15 , 26 , July 10 , 24 , and August 14 , the last day of the war . It is said that more than 10 , 000 civilians died in these bombings in Osaka , Japan . Importance . Osaka was the second largest city in Japan , with a population of 3 , 252 , 340 in 1940 . Traditionally , it was the most important industrial concentration in the Far East . Osaka was one of the principal centers of heavy industry , noted for its shipbuilding , iron , steel , rolling stock works , as well as non - ferrous metals enterprises ( notably copper and aluminum ) . In addition , it was outstanding for its production of aircraft propellers and governors , munitions and ordnance , textiles , special steels , wires , electrical equipment , chemicals , instruments , and machines and machine tools , particularly anti - friction bearings . It had also become a transportation center , and ranked third as a port . Much work had been done to develop its naturally shallow harbor . Lastly , it was the center of an extensive system of railways . First air raid - March 13 – 14 , 1945 . The first air raid on Osaka lasted for about three and a half hours from 23 : 57 on March 13 , 1945 to 03 : 25 . A total of 274 B - 29 heavy bombers attacked Osaka . At first , 43 bombers of the 314th Bombardment Wing flew from Guam island . It was a low - level night raid from an altitude of about 2 , 000m aiming at the local civilian housings . The pathfinder dropped napalm bombs at a target in Minato ward and made a conflagration . The following bombers dropped incendiary cluster bombs around the point . Then , 107 bombers of the 313th Bombardment wing arrived from Tinian and attacked Naniwa ward . Finally , 124 bombers of the 73rd Bombardment Wing from Saipan arrived and attacked Kita ward and Nishi ward . This bomb raid resulted in 3 , 987 dead and 678 missing . Results . There were 274 aircraft that dropped a total of 1 , 733 tons of bombs on the primary target ( Osaka urban area ) . One B - 29 bombed an unknown target and one bombed Chichi - jima . Five B - 29 ’ s bombed Ujiyamada , Kobe , Shirama , and Kushimoto . The destruction of Osaka was almost entirely concentrated in one area southwest of Osaka Castle . Total damage amounted to about 8 . 1 square miles destroyed . Thirteen numbered targets received damage . Two U . S . aircraft were lost . One was lost from an accident and one from an unknown reason . The U . S . suffered no crew member casualties during this mission . The aircraft lost from the accident crashed and burned on take - off , but all crew members escaped . Last air raid - August 14 , 1945 . The eighth bomb raid was executed on August 14 , 1945 , the day before the end of the war . Approximately 150 B - 29 ' s raided Osaka . They dropped about 700 1 - ton bombs , targeting the Japanese Army ' s factories in Eastern Osaka . Four units of 1 - ton bombs were also dropped onto Kyobashi Station of the Japan National Railway nearby around 1pm , resulting in substantial damage to the civilian - filled station . This air raid was also called " Kyobashi Station Bomb Raid " . There were two trains that had just arrived at the station when the bombs were dropped . The victims of the air raid in this station counted more than 210 dead civilians identified , more than 500 unidentified . References . XXI Bomber Command , Tactical Mission Report , Mission # 42 , 13 – 14 March 1945 .