Iruma Air Base (Iruma-kichi, Johnson Air Base, Irumagawa Airfield)

Iruma Air Base is located in Sayama, Saitama Prefecture, Japan, north of Tokyo. Established in 1937 by the Imperial Japanese Army Air Force (IJAAF) as Irumagawa Airfield, the site opened in 1938 and functioned as the Imperial Japanese Army Air Force Academy. During World War II, the IJAAF 14th Sentai operated Mitsubishi Ki-67 medium bombers from the airfield. In September 1945, the United States Army Air Forces occupied the site, renaming it Johnson Air Base. During the Korean War, the base hosted the 35th Fighter Group, 4th Fighter Wing, and 3d Bombardment Wing, operating aircraft including the F-80 Shooting Star, F-86 Sabre, and B-26 Invader.

The Japan Air Self-Defense Force (JASDF) established the Central Air Defense Force headquarters at the installation in 1958. Management transitioned from United States Air Force control to the JASDF in 1963, and the United States returned the final facilities to the Japanese government in 1978.

The JASDF currently operates the base, which hosts the Air Defense Command Headquarters Flight Group and the 2nd Tactical Airlift Group. Primary tenant units include the Flight Check Squadron, Central Air Command Support Squadron, Electronic Warfare Squadron, Electronic Intelligence Squadron, and the Iruma Helicopter Airlift Squadron. The base also hosts an Air Rescue Wing. Aircraft types operated from the facility include Kawasaki C-1 and CH-47J transports, Kawasaki T-4 trainers, and U-4 multi-purpose aircraft. Specialized electronic warfare and intelligence variants of the NAMC YS-11, the Kawasaki EC-1, and U-125 aircraft are also stationed at the base.

Infrastructure supports tactical airlift, electronic intelligence, and flight inspection missions. The base hosts an annual public air show on November 3, which includes flight demonstrations by the Blue Impulse aerobatics team and ground displays of equipment from all branches of the Japan Self-Defense Forces.