Narimasu Airfield Ruins (Hikarigaoka Park)

Narimasu Airfield (成増飛行場, also known as Takamatu Airfield / 高松飛行場) was an Imperial Japanese Army military airfield located in what is now the Hikarigaoka district spanning Nerima Ward and Itabashi Ward in northwestern Tokyo. The airfield was one of the key installations in the defense of the Japanese capital against American strategic bombing during the final years of World War II.

Following the shock of the Doolittle Raid on April 18, 1942, the Imperial Japanese Army began urgently expanding the capital's air defense network. In June 1943, the Army requisitioned approximately 62 hectares of agricultural land in the Narimasu area (then part of Itabashi Ward, Tokyo; now Nerima Ward) and commenced construction of a military airfield. Approximately 2,000 workers — including army engineer units, mobilized students, and local laborers — were deployed for construction. The 1,200-meter runway was oriented roughly north-south, and the airfield was completed on December 21, 1943, when the 47th Air Regiment made it its base.

From March 1944 the airfield's units came under the newly formed 10th Air Division (第10飛行師団) responsible for the air defense of Tokyo and the Kanto region. The primary unit based at Narimasu was the 47th Air Regiment (飛行第47戦隊), one of the Imperial Japanese Army Air Force's most formidable interceptor units. The 47th Sentai had originally been formed as a single squadron (Chutai) in 1941 and deployed to Southeast Asia, where it saw combat over Malaya and the Dutch East Indies flying Nakajima Ki-44 Shoki ("Devil Queller," Allied code name "Tojo") interceptors. Following the Doolittle Raid, the unit was recalled to Japan and expanded to a full three-squadron Sentai, stationed at Narimasu specifically for capital defense.

The Ki-44 Shoki was ideally suited for this mission. Unlike the more maneuverable but slower Ki-43 Hayabusa, the Shoki was designed as a high-speed, high-altitude interceptor with a powerful climb rate — critical attributes for engaging B-29 Superfortresses flying at altitudes above 8,000 meters. The 47th Sentai's Shokis were armed with two 12.7mm machine guns and two 40mm Ho-301 cannons, the latter specifically intended for use against heavy bombers.

When B-29 raids from the Mariana Islands began in November 1944, the 47th Sentai at Narimasu proved to be among the most effective interceptor units in the defense of Tokyo. However, the extreme altitude at which B-29s operated — often above 9,000 meters — meant that conventional aerial combat was extremely difficult. In response, on November 17, 1944, the commander of the 10th Air Division ordered the formation of "Shinten Seiku Tai" (震天制空隊, "Heaven-Shaking Air Superiority Unit") special attack squads within each of his subordinate air regiments. The Narimasu-based unit stripped their Ki-44 fighters of weapons, ammunition, and armor plating to reduce weight and maximize altitude performance. Pilots were trained to climb to B-29 altitude and deliberately ram the bombers in mid-air, with the expectation (though not guarantee) that pilots would bail out by parachute after the collision.

The Shinten Seiku Tai represented a unique form of special attack: unlike naval kamikaze units, the pilots were theoretically expected to survive and fly again. In practice, survival was extremely rare. The unit's formation was accompanied by the ceremonial beating of the Yamaga-ryu war drums (山鹿流陣太鼓), invoking the spirit of the 47 Ronin — a deliberate symbolic parallel to the unit's desperate mission.

The airfield also housed the 43rd Airfield Battalion (第43飛行場大隊) and a maintenance detachment of the Tachikawa Army Air Arsenal (立川陸軍航空工廠成増出張所). As the war progressed, the 47th Sentai transitioned to the newer Nakajima Ki-84 Hayate ("Frank") fighter, which offered superior performance at all altitudes. By 1945, the airfield also served as a staging base for various special attack squadrons, including the 48th and 231st Shinbu-tai (振武隊) special attack units.

The airfield was bombed by B-29s on March 9 and April 5, 1945, and the 47th Sentai moved to Miyakonojō West Airfield in Kyushu on May 27. The airfield continued operations until Japan's surrender on August 15, 1945.

After the war, the United States military occupied the former airfield and surrounding area. In 1947, the site was developed into "Grant Heights" (グラントハイツ), a large American military dependent housing complex named after President Ulysses S. Grant. Grant Heights became one of the largest U.S. military housing areas in Japan, featuring schools, a chapel, a theater, a commissary, recreational facilities, and housing for thousands of American military families. The former runway alignment became the main road through the complex.

Grant Heights was returned to the Japanese government on September 30, 1973, as part of the broader consolidation of U.S. military facilities in Japan. After years of planning, the site was redeveloped beginning in 1983 into the Hikarigaoka (光が丘, "Hill of Light") residential district — a massive modern housing complex of high-rise apartment buildings — and Hikarigaoka Park (光が丘公園), a public park of about 60 hectares that had first opened in 1981.

Within Hikarigaoka Park, near the Keyaki Plaza (けやき広場), a Peace Memorial Monument (平和祈念碑) was erected in 1995 on the 50th anniversary of the end of World War II. The monument's inscription commemorates the history of the site — from the forced requisition of farmland for the airfield, through the sacrifices of the young pilots who flew from Narimasu, to the postwar American occupation and the eventual creation of the peaceful residential community. A separate memorial stone placed by the Narimasu-kai (成増会, the veterans' association of former airfield personnel) also marks the site.