William Kumamoto was a major manufacturing base of airplanes and center of logistics during WWII. The Army Aviation Headquarters was located in Ikeda-cho, and two Mitsubishi aircraft factories producing the Ki-67 heavy bombers were located in Kengun (where the headquarters of Japan’s Western Army remains) and Obiyama-cho. Small plants producing airplane parts were spread throughout the prefecture.
US bombing of these facilities began in March, 1945, increasing in ferocity, with the largest coming on July 1st and 2nd and culminating on August 10. Collectively known as the Kumamoto Air Raid, by war’s end, some 30% of the city, including Shinshigai, Shimotori, Suidocho, Oe, Shinyashiki, Suizenji, Kusaba, and Kurokami, was destroyed by 1,007 tons of bombs and incendiary weapons.
On the northwestern corner of the densha bridge and Shirakawa stands a monument to this. It lists the areas bombed and notes, “11,000 households were affected, 43,000 were victims, 469 were killed, and 552 were injured. To mourn the spirits of the victims and pray that war will not be repeated.” During this time of year, the monument deserves a visit.
Link to a history of the bombings (Japanese): https://www.soumu.go.jp/main_sosiki/daijinkanbou/sensai/situation/state/kyushu_05.html