Malayan campaign

By 1941 the Japanese had been engaged for four years in trying to subjugate China. They were heavily reliant on imported materials for their military forces, particularly oil from the United States.[16] From 1940 to 1941, the United States, the United Kingdom, and the Netherlands imposed embargoes on supplying oil and war materials to Japan.[16] The object of the embargoes was to assist the Chinese and encourage the Japanese to halt military action in China. The Japanese considered that pulling out of China would result in a loss of face and decided instead to take military action against US, British and Dutch territories in South East Asia.[16] The Japanese forces for the invasion were assembled in 1941 on Hainan Island and in French Indochina. This troop build-up was noticed by the Allies and, when asked, the Japanese advised that it related to its operations in China.

When the Japanese invaded, they had over 200 tanks, consisting of the Type 95 Ha-Go, Type 97 Chi-Ha, Type 89 I-Go and Type 97 Te-Ke.[17] In addition, they had nearly 800 aircraft available. Commonwealth troops were equipped with the Lanchester 6x4 Armoured Car, Marmon-Herrington Armoured Car, Universal Carrier and only 23 obsolete Mk VIB light tanks (in the 100th Light Tank Squadron of the Indian Army), none of which were sufficiently armed for armoured warfare.[5] They had just over 250 combat aircraft, but half of these were destroyed inside the first few days of combat.

Between the wars, the British military strategy in the Far East was undermined by a lack of attention and funding. In 1937, Major-General William Dobbie, General Officer Commanding (GOC) Malaya (1935–39), looked at Malaya's defences and reported that during the monsoon season, from October to March, landings could be made by an enemy on the east coast and bases could be established in Siam (Thailand). He predicted that landings could be made at Songkhla and Pattani in Siam, and Kota Bharu in Malaya. He recommended large reinforcements to be sent immediately. His predictions turned out to be correct, but his recommendations were ignored. The British government's plans relied primarily on the stationing of a strong fleet at the Singapore Naval Base in the event of any enemy hostility, in order to defend both Britain's Far Eastern possessions and the route to Australia. A strong naval presence was also thought to act as a deterrent against possible aggressors.[18]

Lieutenant-General Arthur Percival, GOC Malaya Command at the time of the Japanese invasion

By 1940, however, the army commander in Malaya, Lieutenant-General Lionel Bond, conceded that a successful defence of Singapore demanded the defence of the whole peninsula, and that the naval base alone would not be sufficient to deter a Japanese invasion.[19] Military planners concluded that the desired Malayan air force strength would be 300–500 aircraft, but this was never reached because of the higher priorities in the allocation of men and material for Britain and the Middle East.

The defence strategy for Malaya rested on two basic assumptions: first, that there would be sufficient early warning of an attack to allow for reinforcement of British troops, and second, that American help was at hand in case of attack. By late 1941, after Lieutenant-General Arthur E. Percival had taken over as GOC Malaya, it became clear that neither of these assumptions had any real substance.[19] In addition, Churchill and Roosevelt had agreed that in the event of war breaking out in South East Asia, priority would be given to finishing the war in Europe. The east, until that time, would be a secondary priority. Containment was considered the primary strategy in the east.

Planning for this offensive was undertaken by the Japanese Military Affairs Bureau's Unit 82 based in Taiwan. Intelligence on Malaya was gathered through a network of agents which included Japanese embassy staff; disaffected Malayans (particularly members of the Japanese-established Tortoise Society); and Japanese, Korean, and Taiwanese business people and tourists. Japanese spies, which included a British intelligence officer, Captain Patrick Stanley Vaughan Heenan, also provided intelligence and assistance.[20]

Prior to hostilities Japanese intelligence officers like Iwaichi Fujiwara had established covert intelligence offices (or Kikans) that linked up with the Malay and Indian pro-independence organisations such as Kesatuan Melayu Muda in Malaya Indian Independence League. The Japanese gave these movements financial support in return for their members providing intelligence and later assistance in determining Allied troop movements, strengths, and dispositions prior to the invasion.[21]

Through the operation of these networks prior to the invasion the Japanese knew where the Commonwealth forces were based and their unit strengths, had good maps of Malaya, and had local guides available to provide them with directions.[22]

In November 1941 the British became aware of the large scale buildup of Japanese troops in French Indo-China. Thailand was seen to be under threat from this build-up as well as Malaya. British strategists had foreseen the possibility of Thailand's Kra isthmus being used by the Japanese to invade Malaya. To counteract this potential threat, plans for a pre-emptive invasion of southern Thailand, named Operation Matador, had been drawn up. By the time the invasion became highly likely the British decided not to use them for political reasons.[23]

As a lower-priority theatre, the Allies had comparatively few modern aircraft to challenge the Japanese. In addition the Allies did not consider Japanese aircraft a significant threat. In 1941 the Allies assumed that Japan would only have a few hundred poor quality outdated aircraft. The respected Janes All the World's Aircraft for 1941 indicated that the Japanese only had a cluster of dated foreign and indigenous aircraft. Japanese pilots were also underrated, considered unlikely to make particularly good pilots.[25]

Prior to the invasion on 8 December there were 75 Allied aircraft stationed in northern Malaya and 83 in Singapore. The only fighter squadron in northern Malaya was No 21 Squadron RAAF that was equipped with 12 Brewster Buffalos.[26] The Japanese had at least 459 aircraft available.[27]

Japanese aircraft at Penang - January 1941

The Japanese Navy's 22nd Air Flotilla (22nd Kōkū-Sentai) with 110 aircraft and commanded by Vice Admiral Matsunaga Sadaichi operating out of three air bases near Saigon took part in the initial attacks on Malaya.[28][29][30]

The 22nd Air Flotilla included the 22nd (Genzan), Bihoro, and Kanoya Air Groups (or Kōkūtai).[30] They were equipped with 33 Type 96 Mitsubishi G3M1 Nell bombers. The Air Flotilla also had 25 Type 96 Mitsubishi A5M4 Claude fighters available.[31] The Genzen Air Group was a key participant in the sinking of the British capital ships HMS Prince of Wales and HMS Repulse off the coast of Malaya on 10 December 1941, losing one aircraft and its crew during the battle. On 22 January 1942, bombers from the Genzan Air Group attacked Kallang Airport in Singapore, and subsequently provided air support for Japanese offensives in Malaya including the landings at Endau.

The Japanese 3rd Air Corps (飛行集団, Hikō Shudan) and three Air Combat Groups (飛行戦隊, Hikō Sentai) of the 5th Air Corps took part in the Malaya Campaign.[32] In total there were 354 Imperial Japanese Army Air Service (IJAAS) first line aircraft involved together with the 110 Imperial Japanese Navy Air Service (IJNAS) aircraft.[28] The Army units were variously equipped with fighters: Nakajima Ki-27 Nate, Nakajima Ki-43 Oscar, Mitsubishi Ki-51 Sonia; bombers: Kawasaki Ki-48 Lily, Mitsubishi Ki-21 Sally, Mitsubishi Ki-30 Ann; and reconnaissance: Mitsubishi Ki-15 Babs, Mitsubishi Ki-46 Dinah.[31]

Most Japanese pilots of the IJAAS units and at least a quarter of the IJNAS pilots had combat experience against the Chinese and the Soviets. They were all very well trained.[32]

Bristol Blenheim bombers of No. 62 Squadron RAF lined up at Tengah, Singapore, 8 February 1941.

Prior to the commencement of hostilities the Allies in Malaya and Singapore had four fighter squadrons: 21 and 453 RAAF, 243 RAF, and 488 RNZAF. They were equipped with the Brewster Buffalo B-399E, a plane that aviation historian Dan Ford characterized as pathetic.[33][34] Its engine had fuel starvation problems and poor supercharger performance at higher altitudes. Maneuverability was poor and the engine tended to overheat in the tropical climate, spraying oil over the windscreen.[35] In service, some effort was made to improve performance by removing the armour plate, armoured windshields, radios, gun camera, and all other unnecessary equipment, and by replacing the .50 in (12.7 mm) machine guns with .303 in (7.7 mm) machine guns.[36] The fuselage tanks were filled with a minimum of fuel and run on high-octane aviation petrol where available.[33][34]

The remaining offensive aircraft consisted of four RAF squadrons of Bristol Blenheim I and IV light bombers (27, 34, 60, 62 Squadrons), two RAAF squadrons (1 and 8) of Lockheed Hudsons, and two RAF squadrons of Vickers Vildebeest torpedo bombers (36 and 100). The Vildebeests were considered obsolete for the European theatre of operations. No 36 Squadron had some Fairey Albacore biplanes. There were also two PBY Catalina flying boats of No. 205 Squadron RAF and three Catalinas from the Royal Netherlands East Indies Army Air Force at Singapore.

The squadrons were beset by numerous problems including inadequate spare parts and a lack of support staff, airfields that were difficult to defend against air attack with no early warning of impending attacks, a lack of a clear and coherent command structure, a Japanese spy in the Army air liaison staff, and antagonism between RAF and RAAF squadrons and personnel. The Japanese through their network of informants knew the strength and disposition of Allied aircraft before they invaded.[35][37]

Many of the pilots lacked adequate training and experience. For example, a total of 20 of the original 169 Buffalos were lost in training accidents during 1941. Those fighter pilots with experience had been trained in methods that were very effective against German and Italian fighters but suicide against the acrobatic Japanese Nakajima Ki-43 "Oscar" and Mitsubishi A6M "Zero". A counter tactic of avoiding dog fights with a slash and run attack was developed by Lieutenant-General Claire Lee Chennault of the Flying Tigers but was too late for the Allied pilots serving in this campaign.[38][39] Two days before the attack on Malaya, No 1 Squadron [RAAF] Hudsons spotted the Japanese invasion fleet but, given uncertainty about the ships' destination and instructions to avoid offensive operations until attacks were made against friendly territory, Sir Robert Brooke-Popham, the Commander-in-Chief of British Far East Command did not allow the convoy to be bombed.[40][41]

Pilots of No. 453 Squadron RAAF responding to a scramble order

On the first day, the focus of the Japanese air assault was on the Allied air bases. Mitsubishi Ki-21 Sallys from the 7th Hikodan bombed the airfields at Alor Star, Sungai Petani, and Butterworth. A total of 60 Allied aircraft were lost on the first day, primarily on the ground.[26] Those Allied fighters that did manage to engage the Japanese performed adequately against the Nakajima Ki-27 "Nate". However, the appearance of ever greater numbers of Japanese fighters, including markedly superior types such as the Nakajima Ki-43 "Oscar" soon overwhelmed the Buffalo pilots, both in the air and on the ground.

While contesting the Japanese landings on Malaya, Hudsons from No. 1 Squadron RAAF based at Kota Bharu became the first aircraft to make an attack in the Pacific War, sinking Japanese transport ship Awazisan Maru, while also damaging Ayatosan Maru and Sakura Maru off the coast of Kota Bharu, for the loss of two Hudsons, at 0118h local time (an hour before the attack on Pearl Harbor). The Squadron was transferred to Kuantan the following day.

By 9 December, Japanese fighters were operating out of Singora and Patani, Thailand, and Kota Bharu airfield was in Japanese hands.[27] The Allies tried to attack Singora airfield. The bombers were intercepted on take-off by a Japanese raid which disabled or shot down all but one. The sole surviving bomber, a Bristol Blenheim flown by Arthur Scarf, did manage to bomb Singora.[42] No 62 squadron had been moved from Alor Star to Butterworth, and on 10 December it was moved to Taiping.

On 10 December, No 21 Squadron RAAF was withdrawn from Sungai Petani to Ipoh, where it was joined on 13 December by No 453 Squadron RAAF. No 453 Squadron had been sent to protect Force Z on 10 December, but arrived after the warships were sinking. On 15 December both Squadrons were pulled back to Kuala Lumpur, receiving replacement aircraft for those shot down or destroyed. Within the first week of the campaign the Japanese had established air superiority. On 19 December the bombers were moved to Singapore, with No 62 Squadron being re-equipped with Hudsons.

One pilot—Sergeant Malcolm Neville Read of No. 453 Squadron RAAF—sacrificed himself by ramming his Buffalo into an Oscar of 64th Sentai over Kuala Lumpur on 22 December.[43][44]

Continued Japanese dominance eventually forced both Squadrons back to Singapore on 24 December, where they were merged until more replacement aircraft could be obtained. No 64 Squadron had run out of aircraft and its surviving ground-crew and airmen were shipped to Burma. RAAF No 1 and No 8 squadrons were amalgamated due to aircraft losses. This left the Allied ground troops and shipping completely open to air attack and further weakened the defensive position.[45] The Genzan Air Group sank Prince of Wales and Repulse on 10 December, which also established Japanese naval supremacy.[46] In comparison, the Japanese army enjoyed close air support from the start of the campaign, and sought to capture bases for their air support to operate from.[47]

On 25 December, the Second division of Squadron 5, Royal Netherlands East Indies Army Air Force was deployed to Singapore, contributing to the Allied cause before being recalled to Java on 18 January. Several Dutch pilots—including Jacob van Helsdingen and August Deibel—responded to a number of air raids over Singapore while stationed at Kallang Airport. They claimed a total of six aircraft, particularly the Nakajima Ki-27 Nate, which fared poorly in Malaya.

On 3 January 1942, 51 disassembled Hurricane Mk IIBs arrived in Singapore along with 24 pilots (many of whom were veterans of the Battle of Britain) who had been transferred to there with the intention of forming the nucleus of five squadrons.[48] The 151st Maintenance unit assembled the 51 Hurricanes within two days and of these, 21 were ready for operational service within three days. The Hurricanes were fitted with bulky 'Vokes' dust filters under the nose and were armed with 12, rather than eight, machine guns. The additional weight and drag made them slow to climb and unwieldy to maneuver at altitude, although they were more effective bomber killers.[49]

The recently arrived pilots were formed into 232 Squadron. In addition, 488 (NZ) Squadron, a Buffalo squadron, converted to Hurricanes. On 18 January, the two squadrons formed the basis of 226 Group. The following day 453 squadron provided an escort of eight aircraft for five Wirraways and four NEI Glenn Martin bombers, attacking Japanese troops on the Maur River. All the Martins and one of the Wirraways were lost.[50]

No 243 Squadron RAF, equipped with Buffalo fighters, was disbanded on 21 January and 232 Squadron became operational on 22 January, the same day the Genzan Air Group attacked Kallang Airport. 232 Squadron thus had the first losses and victories for the Hurricane in Southeast Asia that day.[51] Most of the bombers were moved to Sumatra midway through January.

Aircraft from 36, 62, and 100 Squadrons unsuccessfully attacked the Japanese invasion fleet at Endau on 26 January, suffering heavy losses. The surviving aircraft were evacuated to Sumatra on 31 January.[52]

In mid-January, the three Sentai of the 5th Air Corps returned to Thailand to participate in the Burma Campaign and the 3rd Air Corps turned its attention to the Netherlands East Indies.[32] In the end, more than 60 Brewster aircraft were shot down in combat, 40 destroyed on the ground, and approximately 20 more destroyed in accidents. Only about 20 Buffalos survived to reach India or the Dutch East Indies.[53] The last airworthy Buffalo in Singapore flew out on 10 February, five days before the island fell.[54] The RAAF and RNZAF fighter squadrons left for Sumatra and Java at the beginning of February.

It is not entirely clear how many Japanese aircraft the Buffalo squadrons shot down, although RAAF pilots alone managed to shoot down at least 20.[55] Eighty were claimed in total, a ratio of kills to losses of just 1.3 to 1. Additionally, most of the Japanese aircraft shot down by the Buffalos were bombers.[35] The Hawker Hurricane, which fought in Singapore alongside the Buffalo from 20 January, also suffered severe losses from ground attack; most were destroyed.[56]