The Imperial Navy opened Kisarazu in 1936 under the Yokosuka Naval District, as a base for the defence of the capital and for links to Iwo Jima, according to Japanese Wikipedia. Its Kisarazu Air Group was, in English Wikipedia’s account, the navy’s first dedicated land-based bomber unit, and it went to war in China from 1937 and later in the Pacific.

The details of its campaigns belong to the war history on the JASDF page and are not repeated here.

On 7 August 1945 Lieutenant Commander Susumu Takaoka took the Nakajima Kikka, a twin-jet attack aircraft, into the air at Kisarazu for a 20-minute test flight. It was the first flight of a Japanese jet aircraft. The only concern, according to Wikipedia, was the length of the take-off run.

Four days later, on 11 August, the second flight went wrong. Rocket boosters fitted to shorten the take-off had been mounted at the wrong angle; when they fired four seconds into the run they pushed the aircraft back on its tail, the pilot aborted, and the Kikka ran into a drainage ditch. It was never repaired. About 23 more airframes were in work when Japan surrendered; three went to the United States for study, and two survive in the National Air and Space Museum collection.

US forces took over in September 1945 and ran the field as Kisarazu Air Base. In 1956 it passed to the Air Self-Defense Force for training, with the US Air Force a tenant until 1961, when its units moved to Tachikawa and the US Navy took their place. In 1968 the Ground Self-Defense Force took control and the JASDF moved to Iruma; in 1975 the remaining US Navy assets moved to Yokosuka, leaving Kisarazu as an auxiliary landing field for the Seventh Fleet.

The 1st Helicopter Brigade, formed at Kasumigaura on 1 March 1968 with two helicopter squadrons, moved to Kisarazu on 25 March 1968. On 19 December 1986 it gained the Special Transport Helicopter Squadron for VIP flights, and in March 2008 its two squadrons were reorganised into the 1st Transport Helicopter Group with four squadrons of CH-47s. Since 27 March 2018 it has reported directly to the Ground Component Command.

The brigade’s heavy lift comes from the CH-47. Japan’s first Chinook contract was for 54 aircraft, 39 of them for the GSDF; Boeing delivered the first CH-47J kits for assembly by Kawasaki in September 1985, and the later CH-47JA has bigger fuel tanks. The GSDF had 47 in March 2022. In 2011 three Japanese CH-47s scooped seawater and dropped it on reactors 3 and 4 of the Fukushima Daiichi plant; the sources reached do not say which unit flew them.

Kisarazu also flies the country’s most important passengers. The Special Transport Helicopter Squadron, formed on 19 December 1986, carries the Imperial family and the prime minister, today in EC-225LPs; Wikipedia records that Japan’s first EC225 was delivered in VIP configuration for the Imperial flight.

In 2014 the Japanese government offered Kisarazu as a maintenance hub for the US Marine Corps MV-22s based at Futenma; after noise tests in October 2016, the maintenance facility opened on 12 January 2017. The GSDF’s own Ospreys, 17 ordered in November 2014 for the Amphibious Rapid Deployment Brigade, were meant for Saga Airport, but talks with Saga Prefecture stalled. The Transport Aviation Squadron was therefore formed at Kisarazu on 26 March 2020, and the first two aircraft were delivered in May 2020.

The arrangement was always temporary. After a US Air Force CV-22 crashed off Yakushima on 29 November 2023, Japan suspended flights of its 14 V-22s until March 2024. In July–August 2025 the Ministry of Defense established Camp Saga and moved the Ospreys there from Kisarazu.