In April 1941 he was appointed as commander of the 64th Sentai, which was at Canton with Ki-27s. The unit received the new Nakajima Ki-43 Hayabusa ('Oscar') and he trained his unit on them prior to the outbreak of the Pacific War.
When the Pacific War started his group escorted naval vessels to Malaya when at the start of December 1941 the 64th Sentai was sent to Duong Dong airfield on Phu Quoc Island to provided cover for the Japanese invasion fleet bound for Malaya during the later part of its journey.
The 64th Sentai became very active in this theatre, and under Kato's command they recorded over 260 aerial victories. He disallowed individual victory credits for the sake of teamwork, and led his men by example in the air. This was quite rare for an officer of his rank to fly routine combat missions.
On the final fighter patrol before dark on 7 December took off from Phu Quoc at 17:30 to relieve Lieutenant Tadao Takayama's 2nd chutai, and comprised half a dozen Ki-43s led by Kato. Due to bad weather conditions and impending darkness, a bomber accompanied them to act as guide on the return flight, but in poor visibility they did not find Takayama's chutai until 19:10. Kato's flight had to terminate its patrol within the hour due to fuel shortage, and set course for home.
Fog, cloud and darkness made it impossible to maintain formation, and three pilots failed to locate the airfield, disappearing without trace into the murky sea.
On 8 December he led the 1st chutai on a low-level strafing attack on Butterworth airfield and the civil airfield at Bayan Lebas on the Island of Penang.
Four Blenheims of 34 Squadron, in the process of being refuelled at Butterworth in preparation for the return flight to Tengah, were damaged and rendered unserviceable. The airfield's defences consisted of just two Lewis machine guns.
Following early morning standing patrols on 22 December, the whole of the reinforced 453 Squadron was ordered off from Kuala Lumpur at 10.00, a dozen Buffaloes taking to the air, led by Flight Lieutenant Vanderfield. These had reached 7,000 feet when six fighters, identified as 'Zeros', were seen and engaged. No sooner had action been joined, than a dozen more of the type appeared, together with others identified as "Messerschmitt 109s". Other Japanese aircraft were reported to have become involved in the big battle, which lasted for over 30 minutes, before the intruders withdrew probably due to fuel shortage.
The main opponents were in fact 18 Ki-43s of the 64th Sentai, led by Kato, which had taken off from Kota Bharu and approached Kuala Lumpur at between 10-13,000 feet. The Buffaloes - estimated at about 15 strong - were initially spotted by Lieutenant Takayama's chutai, which immediately dived to attack. The other chutai followed and in all a total of 11 Buffaloes were claimed shot down, with the other four as probably destroyed! Kato almost certainly claimed one of the Buffaloes. The Japanese unit only lost Lieutenant Takayama (he was credited with three of the claims).
453 Squadron lost three Buffaloes and got four damaged (at least one of them was a write-off) while five returned undamaged.
Sergeant Mac Read in W8209/F was last seen ramming or crashing into an opponent, Sergeant Scrimgeour in W8211 was wounded in a head-on attack and bailed out of his stricken fighter and Sergeant Board in W8216 safely baled out after having been shot down.
Pilot Officer Livesey in AN184 was wounded and Pilot Officer Bob Brury in AN204 was fatally injured when they crash-landed when returning to base. Sergeant Griffith landed a damaged AN175 with a wounded left hand while a wounded Sergeant Collyer landed his damaged AN180 at Sembawang.
The British pilots claimed three destroyed and six probables.
Japanese aircraft attacked Rangoon on 25 December 1941. The units of the 7th Hikodan were off first, 27 Ki-21s from the 12th Sentai and 36 more from the 60th Sentai, escorted by 25 Ki-43s from the 64th Sentai. The 10th Hikodan followed with eight Ki-21s from the 62nd Sentai and 27 Ki-30s of the 31st Sentai escorted by 32 Ki-27s of the 77th Sentai. Four Ki-44s of the 47th I F Chutai provided patrols over Don Muang in case of attack during take-off or landing. The commander of the 7th Hikodan, Wing Commander Kenji Yamamoto, flew in the leading aircraft of the 12th Sentai together with the 12th Sentai commander, Colonel Kumao Kitajima.
Before takeoff from Don Muang, the CO of 64th Sentai, Major Kato, told his pilots:
"We must drive away the enemy fighters from our bombers like a paper fan against flies."
On the way the leading Ki-21 of the 12th Sentai with Yamamoto and Kitajima, suffered an engine failure and turned back. The other bombers followed, but realized something was wrong, resumed their original course and proceeded separately from the main force, but still escorted by some of the Ki-43s (from 64th Sentai).
Due to the lack of a proper Operations Room at Mingaladon following the damage suffered after the attack on 23 December, no adequate warning was given to the Allied fighters and most were scrambled rather late. However, three P-40s of the 3rd Sq., AVG, were already up on patrol and these reported a huge bomber formation on the way. Three more went up, meeting the raiders ten miles from Mingaladon, where the Japanese force split into two, half heading for the airfield and half for the city. The AVG went off after the latter and Flight Leaders Haywood and Older (P-8157) each claimed two of these shot down, whilst Flight Leaders Hedman and McMillan claimed three apiece. Return fire hit the latter’s aircraft, shattering the windscreen and damaging the engine, obliging him to carry out a forced-landing near Thongwa, south-east of Rangoon with a flesh wound in his arm. Haywood’s aircraft was also hit, bullets damaging his port wing. Having broken the bombers’ formation, the remaining P-40s – now joined by others – climbed again before diving on scattered pairs and trios. At that point 20 more bombers with eight fighters were seen approaching, and giving up the attack on the first formation, the Americans climbed from below to attack these.
Flight Leader R. T. Smith (in ‘77’) claimed one that “started smoking badly and dove out heading for the ground”, while Hedman, having already claimed three bombers, attacked another three as they were leaving formation and reported that one blew up in mid air. He then chased a fighter, which he identified as a ‘Navy Zero’, for ten miles before claiming this as his fifth victory of the action. With his canopy shot away, he then made a dead-stick landing on the satellite airstrip at Pegu. Overend claimed two bombers, reporting shooting the wing off the second, but he was then attacked by a fighter and had to make a crash-landing in a paddy field with his aircraft shot full of holes. Smith meanwhile engaged a ‘Type 0’ fighter head-on until “he was in flames and went down in the Gulf” – and then he reported shooting down another bomber, plus two more damaged off the Gulf of Martaban. Curtis E. Smith (making his first and only operational flight with the AVG) also claimed two bombers damaged.
The pilot of the three patrolling P-40s, which were further out, spotted 27 bombers escorted by fighters identified as ‘Zeros’ (obviously the 64th Sentai’s Ki-43s) at 18,000 feet over Mingaladon. Flight Leader Parker Dupouy and Fred S. Hodges attacked two, Dupouy claiming one shot down, which he believed was a ‘Messerschmitt 109’, and Hodges the other as a probable – claimed as a ‘Model 0’. Having also claimed a ‘Model 0’ shot down, Flight Leader William N. Reed attacked a bomber and believed he had hit the tail gunner, but this aircraft was then attacked by a Buffalo, which set the starboard engine on fire. Reed then had to dive away from the fight to clear his guns after they had jammed. Dupouy and Reed then pursued three fighters out over the Gulf of Martaban, Reed claiming one shot down in flames and Sergeant Major Shigekatsu Wakayam (Sho-4) of the 64th Sentai was killed. Dupouy, whose guns jammed, rammed a second, losing four feet off the port wing of his aircraft (‘72’); he reported that his opponent lost its complete starboard wing and was seen to spin down and crash. This was 23-year-old First Lieutenant Hiroshi Okuyama (Class 52) of the 64th Sentai, who was killed. William Reed described the combat in his diary:
"I saw another P-40 who was also leaving the scrap. By now we were 140-150 miles across the gulf from Rangoon. I joined the other ship and saw that it was Dupouy. We started back across the gulf at 17,000ft, and had only gone about 30 miles out off the shore of Moulmein when we spotted three Model Os in a V-formation below us, apparently heading home. We dropped down on their tails and surprised them. Dupouy was following me as I picked out the right-hand wingman. I fired from about 50 yards, and Dupouy fired behind me. The Jap exploded right in front of my face. I pulled sharply up to the right to avoid hitting him, and Dupouy pulled up to the left. In doing so, his right wing clipped the other Jap wingman's ship right in the wing root, and the Jap spun into the gulf, too."
It seems that Reed and Dupouy had scored the first two P-40 vicotries over the Ki-43.
Soon after the action had begun, two pilots of Dupouy’s flight – Bob Brouk and Lewis Bishop – heard over the R/T an order to “pancake immediately”. Believing this to be an order from Dupouy to return to Mingaladon, they had just lowered their wheels to land when six Ki-27s appeared over the airfield and attacked. Although both P-40s were hit, they were able to get away. Bishop subsequently claiming a bomber probable and two damaged. As the Japanese force departed, Brouk claimed a Ki-27 ten miles east of Rangoon, while a few minutes later Flight Leader Ken Jernstedt claimed a ‘Zero’ east of Kyaikto, and Older claimed another – for his third victory – over the Gulf of Martaban, to bring AVG claims to a highly optimistic 24 destroyed, two probables and seven damaged!
The Buffaloes of 67 Squadron had also seen heavy action. Two formations were ordered to patrol in the vicinity of Mingaladon – Flight Lieutenant J. Brandt (W8213) leading six aircraft of ‘B’ Flight in two vics of three (Blue and Green Sections) at 12,000 feet, while Flight Lieutenant Colin Pinckney (W8144/C) patrolled ten miles east of Rangoon with six aircraft of ‘A’ Flight in line abreast at 17,000 feet. Two other Buffaloes flown by Flying Officer Bingham-Wallis (W8146/D) and Sergeant Gordon Williams (W8228) flew top cover to this formation, 3,000 feet higher.
Two formations of enemy bombers were spotted and the top cover attacked the first formation. Bingham-Wallis and Williams together claimed one bomber, which reportedly crashed into the sea. Bingham-Wallis then claimed one of the escorts (reported as a ‘Type 0’; obviously one of the Ki-43s from the 64th Sentai) as a probable while Williams claimed one fighter as a probable. The main formation from 67 Squadron also attacked but 25-year-old Sergeant John Macpherson (RNZAF no. 41486) (AN216) was shot down by the escorting Japanese fighters and he was killed. The remaining aircraft from ‘A’ Flight engaged the fighters, mainly identified as ‘Type 96s’. Sergeant Charles 'Ketchil' Bargh hit one during a 20 minute dogfight, and saw it trail smoke. He was then chased down to ground level by a Ki-43, which he eventually managed to evade. Three more Ki-43s bounced Sergeant K. A. Rutherford as he was attacking a bomber, but he returned safely to Mingaladon. Pilot Officer G. S. Sharp and Sergeant E. E. Pedersen dogfought a number of the Ki-27s for 15 minutes, Sharp claiming one probable before his own aircraft was hit; he force-landed at Mingaladon with some controls and electric cables cut and bullet holes in the ammunition tank. The recently fitted armour plate behind his seat had saved him from injury. Sergeant Pedersen returned safely claiming to have damaged two ‘Type 96’ fighters. Flight Lieutenant Pinckney also claimed a damaged enemy fighter.
The Blue Section of ‘B’ Flight was also engaged with the fighters and Flight Lieutenant Brandt claimed one of them. Brandt’s Buffalo suffered some damage during the action when bullets pierced the petrol tank and aileron; other struck the armour plating behind his back. One of the fighters that attacked Brandt was claimed shot down by Sergeant E. H. Beable. He then made several more attacks and claimed a second fighter as a damaged. His own aircraft also suffered bullets through the airscrew, R/T, fuel tank and wing, though he was able to return to base safely. Sergeant J. G. Finn (W8240) claimed one fighter shot down in flames. His Buffalo received bullet holes in the tail and lower fuselage.
The green Section of ‘B’ Flight, however, suffered heavily. The leader 23-year-old Flight Lieutenant John Lambert (RAF no. 40924) (W8220/U) crashed near Rangoon; he had been shot in the back and had bled to death. The other two aircraft of the section was also shot down and 19-year-old Sergeant Edward ‘Ted’ Hewitt (RNZAF no. 405269) (W8248) and 19-year-old Sergeant Ronald ‘Ron’ McNabb (RNZAF no. 404393) (W8206) were both killed.
Totally the 67 Squadron claimed one bomber and three fighters destroyed, four fighters probably destroyed and three more damaged. Together with the AVG claims this brought the total to 16 bombers and 12 fighters destroyed, 1 bomber and 4 fighters probably destroyed, 7 bombers and 3 fighters damaged for the loss of two P-40s and four Buffaloes; four RAF pilots were killed.
The separate 12th Sentai suffered most heavily, losing three Ki-21s over the target area, while a fourth was badly hit and later force-landed. Most others in the formation were hit, and two or three crewmen were killed in these. The following 60th Sentai was also attacked, and reported that several of its bombers were damaged, but none actually lost. The bombers of the 10th Hikodan didn’t suffer any losses. The escorting fighters were involved in numerous dogfights; the 64th Sentai became broken up and lost two Ki-43s to the opposing fighters (Okuyama and Wakayama), and only the commanding officer, Major Kato, was able to stay with the bombers during the return journey. The 77th Sentai lost two Ki-27s in the fight when First Lieutenant Masashi Someya (Class 52) was killed and Sergeant Major Kontetu Ri (Sho-2) was shot down and taken POW. A third damaged aircraft later force-landed.
The Japanese also heavily overclaimed. Kato and his pilots of the 64th Sentai claimed ten Allied fighters shot down (two by Kato; one possibly Edmund Overend and one Buffalo by Lieutenant Yohei Hinoki), while the 77th Sentai claimed seven more and four probables. Claiming pilots of the 77th Sentai were Lieutenant Kisaji Beppu, Sergeant Major Matsunaga, Sergeant Niino, Lieutenant Yoshihide Matsuo, Sergeant Major Akamatsu (and one probable), Sergeant Ono (who force-landed on return) and Lieutenant Tsuguo Kojima. The last three probables were claimed by Captain Mitsuhiro Matsuda, Captain Toyoki Eto and Warrant Officer Kitasaka. The gunners of the 12th Sentai claimed no less than 19 fighters shot down!
Mingaladon was heavily bombed. Three Buffaloes at dispersal were destroyed or damaged beyond repair and five more, which were awaiting final assemble, were lost in one of the bombed hangars. The runways were pitted with craters and practically unserviceable, returning fighters landing with difficulty – but fortunately without accident. In Rangoon, civilian casualties were estimated to 5000 killed.
During the mid-morning on 20 January 1942, the 64th Sentai escorted Ki-21s from the 12th and 60th Sentais, which were out to raid Seletar.
Twelve Hurricanes from 232 Squadron scrambled from the field at 07:00. They reached 28,0000ft and were ordered by Ground Control to attack the +80 bombers that were some 8,000ft below them. The escorting Japanese fighters, which were at 22,000ft, saw the Hurricanes diving after the bombers and climbed to intercept them. They wasn’t seen by the by the leader, Squadron Leader Leslie N. Landels (RAF no. 84695) and he was shot down and killed by a Ki-43 flown by First Lieutenant Yonesaku Hatta (Class 53). Landels’ Hurricane (BM906) struck the mast of a Chinese fishing vessel before crashing into the sea. Hatta’s triumph was however short-lived since he was immediately attacked by Landel’s no.2 ‘A’ Flight’s Pilot Officer 'Jimmy' Parker who shot him down, killing him in when his fighter crashed vertically into the sea.
Flight Lieutenant Murray Taylor’s section swept down on a formation of 27 Ki-21s flying in their usual three vics of nine; they claimed eight of these shot down, plus three more probably destroyed. Taylor personally claimed two, as did Sergeants Geoff Hardie (BG810), 'Sam' Hackforth (BG720) and 'Joe' Leetham (BE579), the three Sergeants also claiming probables. Despite the assault, the bombers continued to their target – Seletar – but failed to cause much material damage on this occasion.
Following the attack on the bombers, the Hurricanes tangled with the 64th Sentai in numerous dogfights, during which two of the latter were claimed shot down by Sergeants Henry Nicholls and 'Ron' Dovell. However, two more of the Hurricanes were lost. 25-year-old Pilot Officer Alphonso C. ‘Tex’ Marchbanks (RAF no. 100523) (an American), was seen to chase after the departing bombers but he was shot down in flames and killed, his aircraft (BG848) crashing some 20 miles north of Kuala Lumpur. The second Hurricane (BG818 also fell in flames, crashing into the sea after Pilot Officer Norman Williams had baled out, severely burned. He was pulled out of the water by native fishermen, who took him to a nearby island and sent a message to Singapore, following which an ASR launch picked him up and returned him to the Island. He was then transferred to hospital for urgent treatment to his injury.
Lieutenant Takeshi Endo was the first to fire at a Hurricane, but he missed in his excitement. He then spotted another formation just below him. Endo watched as a Ki-43 turned towards the RAF fighters, waggling its wings as its pilot signalled an attack. It dived on one of the Hurricanes, and after a six-second burst of cannon fire, the RAF machine belched flame. Endo then saw a white parachute canopy. He also noticed the slanting white line on the wings of the attacking Ki-43, indicating that it was Major Kato's aircraft. The 64th Sentai totally claimed five Hurricanes shot down during this fight, one of these being credited to Major Tateo and one to the killed Hatta. Apart of the loss of the latter, two other Ki-43s failed to return and both First Lieutenant Takashi Takeyama (Class 52) and Sergeant Major Junki Saito (NCO81) were reported missing.
This was the first clash between Hurricanes and Ki-43s and it ended in a draw – no bombers seems to have been lost on this occasion.
Following the collapse of the British defence on Malaya and in preparations for the invasion of Sumatra in mid February 1942, the 64th Sentai started to operate against this Island.
At first light on 6 February, Japanese aircraft were out to raid Palembang airfield. Due to low cloud ceiling only the 64th Sentai were able to penetrate the cloud. The Japanese pilots didn't achieve much on this occasion, claiming only one aircraft burned, five probably destroyed and five damaged all on the ground before they were forced to break off the attack due to cloud. Kato reported:
"Steering to the north below cloud layers, I spotted a runway. Started firing at once. Although there were many planes on the ground, I could not pierce through the clouds, which were hanging low. Accordingly, after smashing two enemy planes, I decided to return."
On 14 February, the 64th Sentai provided escort for the paratroops landing at Palembang and in the ensuing combat with scrambling British fighters the Japanese pilot first shot down a lone Hurricane from 258 Squadron flown by Flying Officer 'Ting' Macnamara, who survived an forced landing with his badly damaged fighter. He was claimed as a shared by three pilots.
Then the Japanese pilots attacked ten Hurricanes and two of these were claimed shot down. Kato claimed one of these.
It seems that RAF actually lost four Hurricanes in this combat when Pilot Officer 'Bill' McCulloch of 232 Squadron and Sergeant Art Sheerin of 258 Squadron were shot down while Flight Lieutenant John Hutcheson and Pilot Officer Noel Sharp both of 488 Squadron crash-landed. All four pilots, who all survived, were part of a group of nine Hurricanes ferried up from Batavia, which stumbled into the Japanese aircraft over Palembang.
After successful occupation of Palembang airfield by Japanese paratroopers, the 64th Sentai started to use this airfield.
On 19 February, he led the first raid on Java when Buitenzorg was attacked soon after 09.30 by five Ki-48s from 90th Sentai escorted by 19 Ki-43s from 59th and 64th Sentais.
The Japanese pilots claimed seven destroyed while losing none of their aircraft. Defending Dutch Buffaloes claimed two destroyed 'Zeros' while losing four aircraft and getting one damaged.
On the same day (19 February 1942), Kato was promoted from Major to Lieutenant Colonel.