On 7 September 1937 three A5Ms led by Lieutenant Chikamasa Igarashi escorted six Type 96 carrier bombers from the Kaga. At 07:50 they were intercepted by a three-aircraft formation of Curtiss Hawk IIIs including Lieutenant Lai Ming-Tang, squadron vice-commander of the 22nd PS (Hawk III no. New-1), Flight leader Lieutenant Lu Ji-Chun of the 23rd PS (Hawk III no. 2303) and Chou Geng-Hsu of the 25th PS near Tai Hue.
Lu and Chou attacked the bombers and claimed one each. The Chinese fighters were then engaged by the A5Ms and tangled with them for half an hour before being able to disengage and return to Nanking at 08:30. When returning Lai’s Hawk had been hit 61 times and Lu had been hit in the buttock. He made an emergency landing and touched ground safely at Nanking Base. In the hospital, he told his fellow pilots how he felt when he was hit:

“When the bullet entered my leg muscles it felt cool and not burning hot. I did not feel any pain then, but realized that a bulging item has lodged in my flesh. Then blood gushed out and soaked my flight suit. It also felt cool, but the sensation of pain increased every second and every ensuing minute. When I landed the plane, the pain was almost unbearable.”

On 19 September 12 A5Ms led by Lieutenant Shichitaro Yamashita of the 13th Kokutai participated in the first air attack on Nanking as escort for the 17 carrier bombers commanded by Lieutenant Commander Tetsujiro Wada. Three fighters from Kaga under the command of Lieutenant Chikamasa Igarashi were also added to the main force and 16 reconnaissance seaplanes also took part in this attack. Engaging in air battle with some reported twenty Curtiss Hawks and Boeing 281s that had risen to intercept them, twelve enemy aircraft and three probables were claimed shot down by the fighters. Totally it seems that the Japanese claimed 33 victories and 6 probables in this combat. Kiyoto Koga of the 13th Kokutai, who participated in his first combat, returned claiming two Curtiss Hawks shot down while shotai leader PO1c Tadashi Torakuma of the 13th Kokutai (also in his first combat) claimed two enemy aircraft. Toshiyuki Sueda of the same unit in his first combat claimed two enemy aircraft (of a total of 9 – 6 in China). One victory was also claimed by Osamu Kudo of the 13th Kokutai over Nanking but his aircraft was hit and he was forced to ditch in the Yangtze River but he was rescued. Juzo Okamoto of the 13th Kokutai claimed his first victory (of a total of 9 – 3 in China) while flying as the number three wingman to Lieutenant Shichiro Yamashita. Of the three fighters from Kaga both Lieutenant Igarashi’s and the number two wingman’s aircraft developed malfunctions and returned but over Nanking PO2c Ki-ichi Oda, who had carried on, claimed two and one probable Curtiss Hawk. Three Japanese carrier bombers and one seaplane were lost.
It seems that they were intercepted by 23 Chinese aircraft; eight Hawk IIIs of the 4th PG, eight Hawk IIIs from the 5th PG and five Boeing 281s and two CR.32s from the 3rd PG. It seems that eleven Chinese aircraft were lost for only one claimed, this one being made by Lieutenant Chen Huai-Min of the 23rd PS, 4th PG (Hawk IIIs), which claimed one Japanese aircraft shot down. Four Chinese pilots were lost in this combat. They were Dai Guang-Jin (Hawk III no.2509), Liu Lin-Qing (Boeing281), Huang Ju-Gu and Liu Chi-Hung, flight leader of the 8th PS (CR.32). Four more Chinese pilots were wounded including flight leader Liu Chung-Wu of the 25th PS (Hawk III no.2101), which was hit in the left leg and returned to Ju-Rong airfield near Nanking. Wu Ting-Chun’s (Hawk III no.2102) leg was also hit by bullets and he made a force landing at Yang-Zhou airfield. Liu Yi-Jun was injured and baled out of Hawk III no.2512 and the same fate fell to Yang Ji-En, which also was wounded and baled out of Hawk III no.2306. Four more Hawk IIIs returned damaged; “IV-1” flown by Captain Mao Ying-Chu, no. 2404 flown by vice-commander Teng Ming-Teh of the 25th PS, one aircraft flown by Chou Geng-Hsu of the 25th PS and no.2405 flown by Chen Huai-Min of the 23rd PS. Two Boeing 281s were also lost in this combat.

Chou Geng-Hsu served with 28th Fighter Squadron of the 5th Fighter Group in February 1938. The squadron was at this time equipped with Gloster Gladiator Mk.Is.

In the early hours of the 9 February, the commander of the 5th PG, Wong Pan-Yang took off from Heng Yang in a Vought V-92C Corsair in order to guide 11 Gladiators from the 28th PS up from Nanchang. When the group ran into a snowstorm Wong’s engine started to play up and he was forced to turn back to Heng Yang. The Gladiators continued on to Nanchang but only eight aircraft made it. Chin Shui-Tin (Gladiator no. 2801) flew low to see if he could find a landmark but ended up crashing into a hill, writing off the aircraft and suffering injuries to the orbit of his right eye. Chou Geng-Hsu (alternatively Flight Leader Chou Yung-Shu) (no. 2805) also got lost during this flight and he had to bail out. Chou Ling-Hsu (no. 2810) became lost and put down at Gaon.

On 27 February 1938 the 28th Squadron Deputy Leader Louie Yim-Qun led five Gladiators on a mission to seek and destroy enemy planes in a response to an alarm indication six unidentified aircraft heading for Shenzhen. Immediately after take off Chen Yuxin in Gladiator #2903 was forced to divert to Baoan due to a nagging engine problem. Louie Yim-Qun and his wingmen, Wu Zhenhua, Chou Geng-Hsu and Li Yu-Rong continued their search. They met two E8Ns at 7000 feet above the Sun Yat-Sen University. As the Gladiators positioned themselves for an attack, the E8Ns wisely avoided confrontation. Louie Yim-Qun and his wingmen thus had to return to base empty handed after 1 hour and 20 minutes in the air.

On 13 April 1938 the Japanese carrier Kaga launched a strike on Canton consisting of three Type 95 (A4N) fighters, three Type 96 (A5M) fighters and 18 Type 94 (Aichi D1A1) dive-bombers. PO1c Jiro Chono in an A5M led the fighters and Lieutenant Nishihara led the dive-bombers. Chono had taken over when the original leader, Lieutenant Hideo Teshima, had to abort due to mechanical problems on his A5M.
At 10:10, jingbao (intelligence) announced the approaching enemy aircraft. Gladiators of the 5th PG were on alert and were scrambled at 10:20 from Tienho airbase. Squadron Leader Wong Sun-Shui led nine Gladiators from the 29th PS and Captain Clifford Louie led nine from the 28th PS to intercept.
Flying in an echelon formation at 15,000ft, the 29th PS Gladiators were to be responsible for CAP above Guangzhou while 28th PS, flying a 3,000ft higher in two formations, were to seek and destroy enemy aircraft. At 10:50 nine dive-bombers at 13,000ft and 15 "pursuits" (actually five fighters and nine dive-bombers) at 17,000ft were spotted by Wong Sun-Shui above Jiangchuan (a hamlet located north-west of Tienhe airbase). It was clear that they were heading for the Tienhe airbase and Wong Sun-Shui wiggled his Gladiator's (no. 2913) wings to warn his wingmen of the approaching enemy fighters and simultaneously accelerated towards the bogeys. He led his flight consisting of Lieutenants Li Yu-Rong and Huang Kwang-Ching in a diving pass on the nine lower dive-bombers, which were in their bomb run on Tienho Airfield.
Wong Sun-Shui shot up one of the D1A1 and sent it down in flames. The top cover of Japanese fighters came down to intervene. Wong Sun-Shui got into a turning fight with one of the A4Ns and claimed to have shot it down (a wreck was found on one of the islands in the Pearl River, which might have been this aircraft). The flight of A5Ms then turned towards Wong Sun-Shui who was, unfortunately, plagued by jamming guns. After only two firing passes, he had only one of his cowl machineguns still capable of firing. Nevertheless, he managed to down one of the A5Ms before another (the lead plane in the flight flown by PO1c Chono) hit him from the left. Wong Sun-Shui was wounded in the left hand and his engine caught fire, forcing him to bail out. His Gladiator came down near Tai-Ho City north east of Canton (the location of this crash was possibly recorded in error. It is likely that crash site was Tai-Ho Hsiang village in Pan-Yu County south east of Canton as the fight had moved to the south east of Canton). While parachuting down, he witnessed his wingman downing another A5M.
The other two Gladiators in Wong Sun-Shui’s flight also came under attack. Li Yu-Rong attacked and shot down a divebomber but he was himself hit from behind and killed by a pursuing A5M. His Gladiator no. 2910 fell in the south-eastern part of Canton City near Chungshan University. Lieutenant Huang Kwang-Ching tried to intervene but was too late. While he was dogfighting Li's assailant, two other Japanese fighters attacked him and hit him a dozen times, puncturing one of the tires on his landing gear. It was probably at this time when Lieutenant Teng Chung-Kai intervened, bouncing Huang's attackers from behind and disrupting their attack, thereby allowing Huang to escape to the north-west. Teng claimed to have downed one of the A4Ns in flames. Continuing his chase of the Japanese planes, Teng claimed to have downed another "Type 95" over Shi-Pai. It is unclear whether Teng claimed this type, i.e. an A4N, specifically as most other pilot-reports claimed only to have engaged "biplanes" (as opposed to monoplanes - i.e. A5Ms). In the heat of combat, it may have been difficult to differentiate between the A4Ns and the dive-bombers.
The remainder of the 29th PS was also kept busy actively attacking other Japanese fighters. Xieh Chuanwo and his wingman Huang Xiaolen fought on despite being outnumbered by the Japanese fighters.
Early in the action Clifford Louie and his 28th PS Gladiators also joined the combat. Clifford Louie and his wingmen Lieutenants Wu Bo-Jun and Chen Yu-Shen dived on the D1A1s as they were dropping their bombs. Louie claimed to have hit one of the D1A1s and sent it descending north east of Tienho Airfield streaming smoke. He then attacked another "biplane" (probably another D1A1) but his guns jammed after about a dozen rounds, forcing him to break off and climb up to a "covering position".
PO1c Tanaka commanded this D1A1 and it ditched after battle damage. Tanaka reported that he had just completed his bomb run when a Gladiator hit him from behind, damaging his engine, which spewed black smoke and sprayed oil over both crewmen. The D1A1 managed to limp out to the mouth of the Pearl River before the engine seized up. Trading height for distance, the D1A1 glided out to ditch. Tanaka and his crewman NAP1/c Katsumiha took to their dinghy but not before stripping the Type 89 machinegun (Japanese version of the Lewis gun) from its swivel mount. Using the gun, the two held off a number of Chinese armed junks long enough for a floatplane commanded by Lieutenant Yowahara to land alongside and picking them up.
As Louie pulled up to a higher altitude, his deputy Lieutenant Kwan Yen-Sun and wingman Leong Kongyung were diving into four A4Ns. Kwan fired a quick burst and the enemy fighters scattered. He managed to damage a fleeing A4N and seeing that the enemy fighter was trailing white smoke (probably from leaking fuel tank) he then attacked two other A4Ns. These returned the fire but his wingman Leong Kongyung broke off the attack from above. Leong then closed in on the tail on an A4N but he had to brake off the attack after malfunctioning machine-guns.
Lieutenant Chou Geng-Hsu followed Louie's Flight down on a firing pass at the D1A1s. He claimed to have fired over a hundred rounds at one of the dive-bombers while diving from 30 degrees above and behind it. He claimed to have pulled up and away after seeing the Japanese plane catch fire. At that point, Chou Geng-Hsu spotted Chono climbing up after him in his A5M. Chou Geng-Hsu dived at Chono and traded shots with the A5M forcing it to dive away.
PO1c Chono and the remaining A4N flown by PO3c Hatsu-o Hidaka attacked Louie's Flight, shooting down Wu Bo-Jun who was killed when his Gladiator no. 2810 crashed near Tai-Ho Hsiang (village) in Pan-Yu County south east of Canton. Chen Yu-Shen was also shot up and badly wounded when he crash-landed Gladiator no. 2812 at Bai-Ke Ao, also in Pan-Yu County. Totally Chono and Hidaka claimed two victories each in this combat.
Lieutenant Chou Ling-Hsu also followed Louie's Flight down on the D1A1s and spotted one circling. Diving from above and behind, Chou Ling-Hsu hit the D1A1 (which he identified as an A4N) making it stream smoke and descend. Fearing that the Japanese planes had an advantage at lower altitude, Chou Ling-Hsu climbed up to a covering position (clearly, the Chinese pilots were confusing the A4Ns with the D1A1s.). After two firing passes, Lieutenant Fan Hsin-Min also saw a Japanese biplane showing "signs of damage" and trying to escape.
Satoru Ono (8 victories – 3 in China) flying one of the D1A1s returned claiming one enemy fighter shot down.
The battle lasted for 40 minutes and the Gladiators landed at 11:40. Li Jahung returned with minor damaged to the wings of Gladiator no. 2908 and Huang Kwang-Ching returned with more than ten bullet holes and a punctured landing-gear tire on Gladiator no. 2917. The 28th and 29th Squadrons claimed at least nine victories in this air combat. It would appear that the Japanese lost at least 5 aircraft, one A5M, two A4Ns and two D1A1s while claiming 15 enemy fighters shot down and 3 probables. The fighter pilots lost were PO1c Naoshi Eitoku (Pilot 13), PO3c Yukio Miyasato (Otsu 3) and PO3c Yuji Mori (Otsu 3). The Chinese found a total of 4 wrecks, which would account for the 3 fighters and almost certainly one of the dive-bombers. One of the wrecks was found at Chi-Ao, which is on an island way out at the mouth of the Pearl River near Macao. That may have been one of the A4Ns that Teng chased away from Lieutenant Huang south east of Canton. The other 3 fell around Canton City, one at Shao-Ho just north east of Canton; one at the Chungshan University Agricultural Department south east of Canton and the third in an island on the Pearl River near Canton. Unfortunately, the types were not identified so it is difficult to match them up.

He served as squadron commander of the 8th PS in 1940 until 2 May 1941.

On 2 February 1940 he crashed-landed and was badly wounded.

Chou Geng-Hsu ended the war with 2 victories, this one claimed while flying Gloster Gladiator.

In some sources his name is given as Zhou Ganju or Zou Geng-Xu. It is possible that Zou Geng-Xu and Chou Geng-Hsu are two different pilots. If so are the combat reports for Chou Geng-Hsu the ones related to 1938.

Claims:

Kill no.	Date	Number	Type	Result	Plane type	Serial no.	Locality	Unit
	1937
1	07/09/37	1	D1A2 (a)	Destroyed	Hawk III		Tai Hue area	25th PS
	1938
2	13/04/38	1	D1A1 (b)	Destroyed	Gladiator		NW Tienhe airbase	28th PS

Biplane victories: 2 destroyed.
TOTAL: 2 destroyed.
(a) Claimed in combat with Type 96 carrier bombers from the Kaga.
(b) The 28th and 29th PS claimed at least nine victories (5 D1A1s, 3 A4Ns and 2 A5Ms) in this air combat while losing four Gladiators. The fighters from the Kaga claimed four victories while losing at least 5 aircraft, one A5M, two A4N and two D1A1. The Chinese found a total of 4 wrecks, which would account for the 3 fighters and almost certainly one of the dive-bombers.

Sources:
Chinese Air Force Gladiators in Action - D. Y. Louie, 1998 Small Air Forces Observer vol. 22 no. 4 (88) December 1998 kindly provided by Santiago Flores.
Japanese Naval Aces and Fighter Units in World War II - Ikuhiko Hata and Yasuho Izawa, translated by Don Cyril Gorham, 1989 United States Naval Institute, Annapolis, ISBN 0-87021-315-6
Much additional information kindly provided by Raymond Cheung, Alex Crawford and Erich Wang.