At the start of the Sino-Japanese war, Chang Kuang-Yun served in the 4th Fighter Wing. This unit was at the time equipped with Curtiss Hawk IIIs.
On 14 August 1937 Chinese intelligence reported that a number of Japanese bombers had taken-off from an airfield Taiwan, crossed the Formosa Strait and were heading north over Chekiang in the direction of Hangchow. At this time Hangchow was only defended by a handful of Hawk IIIs flown by instructors from the Central Chinese Aviation Academy since reinforcements from Chaocharkoa hadn’t been able to fly in due to bad weather. However barely had the warning been received when a number of Hawk IIIs from the 21st and 23rd Squadrons of the 4th Fighter Wing landed. These fighters were under the command of Colonel Kao. The newly arrived fighters were hurriedly re-fuelled but this was far from complete when the air alarm started. The Hawks scrambled and turned south to intercept the intruding bombers. The Chinese fighter were still climbing when the Japanese bombers were seen approaching, these quickly being identified as the newly-introduced Mitsubishi G3M2 Model 21 long-range aircraft of the Imperial Navy’s Kanoya Kokutai that had taken-off from their base at Taipei some 565 km to the south bout two-and-a-half hours earlier. The Japanese bombers, of which there were about a dozen, were flying in a loose group at an altitude of 4300 meters, their crews evidently anticipating no opposition from fighters. The appearance of the Hawk IIIs was totally unexpected and the Chinese fighters were among the Japanese bombers before they were aware of their existence. Recovering from their surprise, the Japanese gunners returned the fire, but the Chinese pilots persistently attacked from below and astern, placing the bombers, which possessed no ventral defensive armament, at a serious disadvantage, their gunners rarely succeeding in bringing their weapons to bear. Several of the bombers changed course towards Nanking, but those that persisted on their original course were constantly attacked, only one succeeding in penetrating as far as Hangchow. This, diving through cloud to attack the airfield, missed its target completely, its bombs destroying a warehouse near the railway yard. It was then pounced on simultaneously by Colonel Kao and his wingman, Tan Won, and promptly exploded. By this time, the Hawk IIIs of 22nd Squadron had arrived over Hangchow and, although low on fuel, joined the combat, harassing the scattered and fleeing bombers until lack of fuel necessitated their return to base. The final tally revealed the destruction of six of the G3M2 bombers without the loss of a single Hawk III. Colonel Kao and his wingman, Tan Won, shared three victories, another pilot, Leh Yi-Chin, claimed two and the sixth bomber was claimed by Chang Kuang-Yun. Although no Chinese fighters had been lost in this combat, several had suffered some degree of damage, among them the Hawk III flown by the Commanding Officer, Colonel Kao, who had been shot through one arm and his engine had taken several bullets. Despite his wounds, however, he made a perfect landing, his damaged engine cutting just as he touched down.
Chang Kuang-Yun ended the war with 1biplane victory, these claimed while flying the Curtiss Hawk III.

Claims:

Kill no.	Date	Number	Type	Result	Plane type	Serial no.	Locality	Unit
	1937
1	14/08/37	1	G3M2 (a)	Destroyed	Curtiss Hawk II I		Hangchow area	4th Fighter Wing

Biplane victories: 1 destroyed.
TOTAL: 1 destroyed.
(a) Mitsubishi G3M2 Model 21s from the Japanese Navy’s Kanoya Kokutai.

Sources:
China Incident (Air Enthusiast/April 1973) - Victor Chun, 1973 kindly provided by Börje Henningsson