Sayama Airfield

Military Conversion and Expansion

The site is the location of the active Iruma Air Base (ICAO: RJTJ), a major and strategic installation for the Japan Air Self-Defense Force (JASDF). It hosts the Air Defense Command Headquarters, the Central Air Defense Force Headquarters, transport squadrons (flying aircraft like the C-1, C-2, and U-4), and an electronic warfare unit. The base is well-known for its large annual air show, which attracts hundreds of thousands of visitors.

The designation 'Sayama Airfield' refers to the historical predecessor of the modern Iruma Air Base. The site was not 'closed' in the sense of being abandoned, but rather transformed. In 1937, the Imperial Japanese Army Air Force Academy (Rikugun Kōkū Shikan Gakkō) relocated to this site, which was then a newly constructed airfield in the Sayama Hills area. The airfield became a primary training center for army pilots. During this period, it was also developed into the Iruma Air Arsenal, a major facility for aircraft testing and manufacturing. The original airfield was absorbed and expanded into this large military complex, effectively ceasing to exist as a separate, smaller entity. After WWII, it was taken over by the United States Air Force and renamed Johnson Air Base, serving as a key logistical and operational hub during the Korean War and Cold War. In 1958, it was returned to Japan and became the Iruma Air Base for the Japan Air Self-Defense Force (JASDF). The ICAO code 'JP-2227' is a non-standard, unofficial identifier, possibly from a historical or flight simulator database; the official ICAO code for the active base is RJTJ.

There are no prospects for reopening 'Sayama Airfield' as it is not a closed or abandoned site. The location is fully occupied and operated as one of Japan's most important military air bases, Iruma Air Base. There are no plans to convert it to civilian use or revert to its historical name.