Koshun Airfield (Hengchun Airfield)

Koshun Airfield (恒春飛行場, also romanized as Hengchun) was located on the Hengchun Peninsula at the extreme southern tip of Taiwan (Formosa), in present-day Hengchun Township, Pingtung County. It was the southernmost military airfield on the island, positioned at a strategically critical location less than 350 kilometers north of the Philippines across the Bashi Channel.

The airfield's origins date to at least 1941, when Japanese military records (飛行機隊戦闘行動調書) indicate it was already operational. Republic of China military documents compiled after Japan's surrender record the airfield's official completion as August 1943, but this likely refers to an expansion or upgrade rather than initial construction. The base fell under the administrative jurisdiction of Takao Province (高雄州) during the colonial period.

In December 1941, with the outbreak of the Pacific War, Koshun Airfield played a direct role in Japan's invasion of the Philippines. The Imperial Japanese Army's 50th Air Regiment (飛行第50戦隊) based Nakajima Ki-27 Type 97 fighters (九七式戦闘機, Allied code name 'Nate') at the airfield. These fighters conducted attack missions against American air assets in the Philippine Islands, taking advantage of Koshun's proximity as the nearest Japanese airfield to Luzon. The 50th Sentai subsequently relocated forward to Philippine airfields as the Japanese conquest progressed.

Taiwan's network of airfields — ultimately numbering 77 Army and Navy facilities by war's end — served as critical staging and transit points for Japanese operations throughout Southeast Asia. Koshun, given its southernmost position, was particularly important for routing aircraft between the Japanese home islands and the Southern Resource Area. By late 1944, Taiwan hosted 15 Army airfields, 11 Navy air stations, and two seaplane bases.

During the Formosa Air Battle (台灣沖航空戰) of October 12-16, 1944, U.S. Navy carrier task forces struck Japanese installations across Taiwan. While the main targets were larger bases at Takao, Okayama, and Shinchiku, the campaign disrupted air operations island-wide. Japan lost approximately 650 aircraft during the five-day battle while inflicting only minor damage on the American fleet, despite wildly exaggerated Japanese claims of sinking 11 carriers and 2 battleships.

By 1945, with Japanese air strength severely depleted, Koshun Airfield was used primarily as an emergency landing field for both Army and Navy aircraft transiting between Taiwan and points south. The airfield sustained multiple Allied air raids between February and June 1945 as part of the U.S. Far East Air Forces' systematic campaign to neutralize Japanese airfields on Formosa and interdict reinforcement routes to the Philippines and Okinawa:

• February 19, 1945: B-24 Liberator heavy bombers attacked the airfield.
• March 3, 1945: Fighter strafing and sweep operations.
• March 6, 1945: Additional fighter sweeps.
• March 18, 1945: Combined attack by B-24s, A-20 Havocs, and fighter aircraft.
• April 20, 1945: P-51 Mustang fighters attacked.
• May 11, 1945: B-24 and B-25 Mitchell bombers attacked.
• May 27, 1945: B-24 and B-25 bombers attacked.
• June 13, 1945: B-24 and B-32 Dominator bombers attacked — among the last raids on the airfield.

After Japan's surrender in August 1945, the Republic of China military took control of the facility. The Hengchun area was subsequently developed as a joint operations training base covering over 2,000 hectares across four southern townships (Hengchun, Checheng, Mudan, and Manzhou), used for live-fire exercises and field combat training by all branches of Taiwan's armed forces.

The airfield itself remained largely unused for civilian purposes for decades. In 1998, the ROC Army displayed surface-to-air firepower at the Hengchun military base. The Ministry of National Defense eventually approved converting part of the facility for civilian use, and the modern Hengchun Airport (IATA: HCN, ICAO: RCKW) opened to the public in January 2004, providing air access to the Kenting National Park tourism area at Taiwan's southern tip. The airport's runway is built on approximately the same alignment as the wartime airfield.