Chofu Airfield (Army Air Defense Base – Capital)

Chofu Airfield (調布飛行場) was constructed beginning in 1939 and opened on April 30, 1941, originally conceived as a public airport but immediately devoted to military use upon the outbreak of full-scale war. The airfield became the principal capital-defense (帝都防空) fighter base for the Imperial Japanese Army Air Service, assigned to the 10th Air Division (第10飛行師団). Its primary interceptor was the Kawasaki Ki-61 Hien ("Flying Swallow"), Japan's only mass-produced liquid-cooled fighter of the war, tasked with engaging USAAF B-29 Superfortress bombers targeting Tokyo. The airfield also served as a transit base for kamikaze units en route to Chiran and southern staging points. As B-29 raids intensified in 1944–1945, 30 individual reinforced-concrete aircraft shelters (掩体壕) were constructed across the surrounding area to protect Ki-61s from strafing and bombing. These distinctive semicircular structures, each sized for one fighter, were built using mobilized high school students and local laborers. Three shelters are preserved and open to the public today, two of them (Ōsawa No. 1 and No. 2) in Musashino-no-Mori Park on the north side of the current airport; a few others remain on private land. Post-surrender, US forces used the field for F-5 Lightning photo-reconnaissance missions mapping war damage until January 1946. The airfield was fully returned to Japan in March 1973 (some sources give 1972) and now operates as a small regional airport.