At the start of the Sino-Japanese war, Huang Yan-Po was serving in the 4th PG. This unit was at the time equipped with Curtiss Hawk IIIs.

During the night of 14 and 15 August, the pilots of the 4th PG at Schien-Chiao airbase had to prepare their fighters themselves since the ground personnel had left the field to take shelter during the air raid on 14 August and had not returned. The pilots carried cans of fuel on their backs from the storage building to the field, punched holes on the cans and fuelled the aircraft themselves. They had not eaten since noon, and were not able to go to bed until 1:30 a.m. They did not sleep long because alarm sounded less than two hours later.
In the early morning on 15 August Colonel Kao Chi-Hang led 21 Hawk III's from the 4th PG to intercept a dawn attack on Hangchow by twelve Type 89 torpedo bombers from the Japanese carrier Kaga. In the confused action in and out of clouds, the 4th PG made 17 claims, more than the total number of Japanese planes in the action. The actual losses were six shot down and two ditched in Hangchow Bay.
Kao quickly shot down one of the Type 89's on the edge of the formation and then attacked another setting it alight. A lucky shot from the starboard quarter hit Kao in the right arm before passing through the instrument panel and damaging the engine in his Hawk No. IV-1. He was forced to land at Schien-Chiao and was out of action for 2 months.
21st PS's Squadron Leader Captain Lee Kuei-Tan in No. 2101 attacked the No. 2 Shotai, shooting down the No. 2 plane over Chao-Er. Two out of the crew of three were seen to bail out but they were over the Chao-er River and probably did not survive. Lee then teamed up with Lieutenant Cheng Hsiao-Yu of 22nd PS in No. 2202 to claim another Type 89. Return fire from the tightly packed Japanese formation was heavy and Lee's No. 2101 received slight damage to its upper wings while Cheng’s No. 2202 took a shot in one of its landing wheels. Cheng’s wingman, 2nd Lieutenant Chang Kuang-Ming also claimed a victory in this combat when he attacked the leader of a group of Japanese bombers. He opened fire with his two machine guns. Tracers and bullets truck his target, and the enemy plane turned into a fireball and plunged out of the sky. He broke off immediately and turned around for another strike.
Lieutenant Huang Yan-Po in No. 2107 attacked the first Shotai, claiming to have shot down the No. 3 aircraft in flames. He too took a shot in the landing wheel. Lieutenant Tan Won in No. 2104 also attacked the same Shotai and claimed another Type 89. This may have been the aircraft of the Kaga's Commander, Air Group (CAG) Commander Iwai who was killed in this action along with his deputy. Lieutenant Wang Wen-Hua caught two Type 89's trying to attack Schien-chiao from the south and shot one down in flames. One of the crew, a young ensign, bailed out and was captured. (This unnamed ensign later defected to the Chinese side and helped translate decoded Japanese radio messages). Lieutenant Yuan Chin-Han in No. 2108 went after the No.1 Shotai in a formation and claimed to have shot down the leader in flames (this may also have been Iwai's plane, it is almost certain that many Chinese pilots shot at the same planes). Lieutenant Liu Chi-Sheng in No. 2102 also claimed one Type 89 over Woong-Chia-Fu but was hit in the fuel tank and force landed at Chaio-shi Airfield where his plane was further damaged by bombing.
Lieutenant Le Yi-Chin from the 22nd PS made no less than 4 claims but these are almost certainly duplicates of other claims or overoptimistic.
Deputy Squadron C.O. Lai Ming-Tang landed to refuel and took off again to claim a shared kill with his wingman Lieutenant Liang Tian-Cheng.
Of the 23rd PS, Captain Mao Ying-Chu, Lieutenant Yang Yu-Ching and Lieutenant Wang Yin-Hua each claimed one Type 89.

On 31 May, the Japanese executed a new attack on the aerodromes of fighters defending the Chinese capital. The Chinese had received advance information and were ready for them, having been able to concentrate aircraft at the Hankou aerodrome already the day before. In all, there were concentrated more than a hundred fighters.
At 10:15, 18 enemy bombers were spotted over Tung Chin by Chinese air defence lookouts followed by a reported 36 enemy aircraft over Lu-Jiang at 10:45. 46 enemy aircraft were spotted over the Camel Pass at 11:45 followed by a report of 39 enemy fighters near Qing-Shan at 12:00.
Thus, at midday a reported 39 enemy fighters and 18 enemy bombers approached Wuhan. At 11:50 49 Chinese interceptors successively began taking off from Wuhan. The Chinese fighters were four I-15bis from the 3rd PG, eight I-15bis and six I-16s (of the 21st PS) from the 4th PG, 21 I-15bis and ten I-16s from the Soviet volunteers. The 31 Soviet volunteers become the main attack force according to a previously devised plan while the 18 Chinese fighters climbed higher to provide an echeloned covering detachment. The fighters patrolled between Hankou and Qing-Shan.
Even before the appearance of the bombers, one of the groups of fighters flown by the Soviet volunteers was attacked at 12:07 by 18 A5Ms at 4500 meters. The Japanese fighter formation was reported to be 39 aircraft flying in a ‘V’ formation with 18 fighters at 4500 meters, 12 at 5000 meters and the high-cover of 9 fighters at 6000 meters. Six I-15bis flown by Soviet volunteers arrived to reinforce but at the same time 18 A5Ms joined the fight, leaving only 3 A5Ms as high-cover. At this them the I-16s from the 21st PS also joined the combat while the rest of the slower I-15bis gradually also did this. The formation led by Captain Cheng Hsiao-Yu, consisting of four I-15bis from the 3rd PG and eight I-15bis from the 4th PG didn’t manage to join combat since they were farthest away when the combat started and when they arrived north-east of the airport the enemy evaded east.
After the bombers appeared, A. Zingaev’s group threw themselves upon them, and with the first attack shot down two. The remaining bombers of the first group and the two remaining groups were not able to force their way through to the aerodrome and they turned back.
According to the recollections of N. G. Kozlov, the encounter with a large group of A5Ms occurred about 15 to 20 km east of the aerodrome. The Japanese attacked leaving one flight at altitude. Following the manoeuvres of his leader, Kozlov in a banking turn gave a burst at a Japanese fighter, which was following K. Opasov. In the turning carousel, this Japanese finally flew directly into the gun sights of Kozlov’s I-15bis, but the burst went into an already burning aircraft. A second Japanese began an attack on Kozlov. For their part, the I-16s conducted a battle in the vertical, diving at a steep angle and hitting the Japanese and then soaring upwards, and opening fire at the moment when the Japanese was dependent on his motor, climbing through a half loop. Mainly attacking out of the sun, the Japanese quickly lost the initiative, which gradually passed to the Chinese, as the battle dissolved into a sharp dogfight and gradually dissipated. While departing Kozlov let off a burst at long range at a Japanese under attack by two I-15bis, and the A5M limply began turning wing over wing and tumbled out of control to the ground.
In this combat Anton Gubenko returned in his damaged aircraft and reported that he had shot down one Japanese and rammed another. Aleksey Blagoveshchenskiy also claimed an enemy aircraft in this combat while Grigoriy Kravchenko claimed two.
Totally the Chinese fighters claimed 14 enemy aircraft shot down after a battle that lasted for 30 minutes. The 21st PS Squadron Leader, Captain Lo Ying-Teh, claimed one enemy aircraft shot down, which crashed south of Hou Lake. Lieutenant Liu Chi-Sheng of the 21st PS returned claiming an A5M, which crashed 20 kilometres north of the airfield. The pilot was seen to bale out. Han Sen teamed up with Huang Yan-Po and jointly they attacked one enemy aircraft five times before it crashed near Tian-Xin Shoal. The Soviet volunteers claimed six enemy aircraft shot down; one crashed at She-Kou, killing the pilot while another crashed 30 kilometres from She-Kou with the pilot parachuting.
The Chinese and the Soviet pilots each lost one pilot and one aircraft and several aircraft were seriously damaged. The 21st PS flight leader, Zhang Xiao-Xian, in I-16 no. 2107 was shot down and crashed in the Dai-Jia Mountain killing Zhang. I-15bis no. 90, flown by a Soviet volunteer, crashed near Hang-Dian but the pilot managed to parachute safely.
The Japanese record that 35 A5Ms (eleven from the 12th and 24 from the 13th Kokutais) escorted 18 G3M2 bombers. Poor visibility in the region of the target led to the fighters of the 13th Kokutai failing to discover the enemy, and the A5Ms of the 12th Kokutai became engaged in a battle against a reported 50 fighters. Nine aircraft of the Yoshitomi chutai of the 12th Kokutai reported tangling with about 50 enemy fighters and during the combat PO3c Yoshimi Minami claimed one enemy aircraft (9 victories in China and a total of 15) and Momoto Matsumura clamed three. He then received a hit in his A5M’s fuel tank; moreover, he found himself surrounded by twelve enemy aircraft. Since he had run out of ammunition, he employed a ramming tactic. Then, despite the fact that the left wing of his aircraft had been sheared off from the red ball of the rising sun outward, Minami started on his way back to base. He made an emergency landing on the banks of the Yangtze River and set his aircraft on fire. Fortunately for Minami, friendly search aircraft were able to spot him; he was rescued by a patrol boat and returned safely to base. One Japanese fighter (Sea1c Hiromitsu Takahara (Pilot 36) of the 12th Kokutai was killed) was lost in the combat. The Japanese fighters totally claimed 18 victories (alternatively 12 and 6 probables) including an old, unarmed Bellanca 28/90 biplane (evidently a reconnaissance aircraft).

Huang Yan-Po ended the war with 1 biplane victory, this one being claimed while flying the Curtiss Hawk III.

Claims:

Kill no.	Date	Time	Number	Type	Result	Plane type	Serial no.	Locality	Unit
	1937
1	15/08/37		1	Type 89 (a)	Destroyed	Curtiss Hawk III	#2107	Hangchow area	4th PG
	1938
	31/05/38	11:50-	1/2	Enemy aircraft (b)	Shared destroyed	I-16		Tian-Xin Shoal area	21st PS

Biplane victories: 1 destroyed.
TOTAL: 1 and 1 shared destroyed.
(a) Claimed in combat with Type 89 torpedo bombers from the Japanese carrier Kaga. The Chinese pilots claimed 17 destroyed enemy aircraft but the actual losses were six shot down and two ditched in Hangchow Bay.
(b) 14 Japanese aircraft claimed in combat for the loss of one I-15bis and one I-16. Japanese fighters from 12th and 13th Kokutais claimed 12 victories (and 6 probables?) for the loss of one A5M.

Sources:
Tidbits from the Sino-Japanese Air Battles - Chang Kuang-Ming, 1998 World News Weekly August 1998 kindly provided by Tom Chan
Information kindly provided by Raymond Cheung, Tom Chan and Erich Wang.