Toyohashi Air Raid The was a strategic bombing operation on the night of 19 June 1945 against the city of Toyohashi , Japan . The air raid was part of the Allies ' aerial campaign against the Home Islands of the Empire of Japan during World War II . Background . During World War II , as now , the city of Toyohashi , Aichi was an important hub in the transportation network of central Japan . Toyohashi Station is located along the Tōkaidō Main Line linking Tokyo and Osaka , and also serves as the origin of the Iida and Atsumi Lines which facilitate access to rural areas of eastern Aichi Prefecture . The city had a fairly small industrial base at the time , but it was more important for its port facilities on Mikawa Bay . In addition to these strategic civilian targets , Toyohashi hosted a number of military targets , such as a large training area for Imperial Japanese Army recruits located near Aichi University , and the headquarters of several army units , including the 18th Infantry Regiment , the 4th Cavalry Brigade , and the 4th Independent Combat Engineer Regiment . Toyohashi also had an airfield that served the 381st Naval Air Group which flew Mitsubishi J2M " Raiden " interceptors . Air Raid . There were nine air raids on Toyohashi between January and June 1945 . About 25 - 30 people were killed in the first eight . These early air raids are barely mentioned in relevant historical texts and were probably the result of Allied bombers hitting Toyohashi as an alternate target or a target of opportunity . Only the ninth raid , by far the largest , became known as " The Toyohashi Air Raid " . Starting late on the night of 19 June or after midnight , in the early hours of 20 June 1945 , 136 Boeing B - 29 Superfortress es conducted a firebombing operation on the city of Toyohashi . The air raid lasted for about three hours , and ended a little before dawn . The areas primarily affected included a large part of the downtown area between Toyohashi Station and City Hall , large sections of the Azumada and Maebata neighborhoods , and neighborhoods around Azumada Elementary School . On the same night as the Toyohashi Air Raid , two other firebombing operations were being conducted elsewhere in Japan . One was in neighboring Shizuoka prefecture , and would become known as the Great Shizuoka Air Raid ( 静岡大空襲 " Shizuoka dai - kūshū " ) . The other was the Great Fukuoka Air Raid ( 福岡大空襲 " Fukuoka dai - kūshū " ) on the island of Kyushu . Results . In the aftermath of the Toyohashi Air Raid , Japanese authorities compiled the following data on the damage done on the night of 19 – 20 June 1945 : Among the buildings that were destroyed were five temples , Azumada Elementary School , and the Kawai Hospital ( which was rebuilt , though it has changed ownership and location several times , and is now the Oshima Orthopedic Clinic in the Ihara neighborhood ) . In 1946 , the United States Army Air Forces estimated that 61 . 9 % of the city had been destroyed . While property damage in Toyohashi was high , casualties were relatively light . This was due in part to lessons learned from the several air raids on neighboring Hamamatsu city , which had suffered much more since its first air raid in February 1945 .