Kasumigaura Naval Airfield

Military Conversion and Dissolution of Original Operator. The original Kasumigaura Naval Airfield, operated by the Imperial Japanese Navy Air Service (IJNAS), ceased to exist following Japan's surrender at the end of World War II and the subsequent dissolution of the Imperial Japanese military. The facility was then occupied by Allied forces before being transferred to the newly formed Japan Self-Defense Forces.

The site is not abandoned; it is an active and critical military installation. It is now known as JGSDF Camp Kasumigaura (ICAO: RJAK), a major base for the Japan Ground Self-Defense Force (JGSDF). The camp houses the JGSDF Aviation School, a primary maintenance and supply depot for JGSDF aircraft (especially helicopters), and several helicopter units. It is a central hub for JGSDF aviation logistics, training, and operations. The ICAO code provided in the query, JP-0857, is an unofficial or outdated identifier; the current, official ICAO code is RJAK.

Established in 1922, the Kasumigaura Naval Airfield was one of the most important and largest air bases for the Imperial Japanese Navy Air Service. It served as the primary flight training center for the IJNAS, where thousands of pilots, observers, and mechanics were trained before and during World War II. It was a hub for developing naval aviation tactics and technology, including early aircraft carrier operations. The base was also home to the Kasumigaura Air Group (Kasumigaura Kaigun Kōkūtai), a prominent training and operational unit. Due to its importance, it was a target for Allied bombing raids in the final year of the war.

Not applicable. The site was never truly 'closed' in the sense of being abandoned. It was repurposed and remains a vital, active military base for the Japan Ground Self-Defense Force. There are no plans or prospects for it to be converted to civilian use or to 'reopen' as its former entity.