The process of planning the Malaya offensive air operation and the awareness of control of the air
By curious coincidence, the Imperial Army and Navy started to plan the offensive operation of strategic vital areas such as Hong Kong, Singapore, Borneo and Malaya, assuming Great Britain as a hypothetical enemy when ‘Air Troops Operations’ was compiled. At first, this offensive operation was the naval plan. But the Imperial Army took responsibility after the Annual Operation Plan of 1939, and saw difficulties with accomplishing the plan. Although the operational concept of Imperial Army Aviation remained the support of ground operations at that time, they realised from current wisdom that air strikes were indispensable at the beginning of a war. However, they did not have the striking range necessary to conduct ‘aerial exterminating action’ before the landing operation in the Malaya offensive operation. To begin with, Type 97 fighters (Ki-27) of the Imperial Army’s mainstay had only 400 kilometres of combat radius. Therefore, it was not possible to escort amphibious squadrons the distance of 600 kilometres across the Gulf of Thailand, even if they could hold some airfields in southern French Indo-China. Secondly, even Type 97 heavy bombers (Ki-21) could only reach northern Malaya.
Eventually, they tried to overcome their difficulties by using tactics where advance elements executed surprise landings and capture of airfields before ‘aerial exterminating action’. This idea was based on the result of a map manoeuvre exercise at the Army Staff College in January 1941. The purpose of this manoeuvre exercise was to evaluate the plan drafted by Lieutenant-Colonel Tanigawa Kazuo of Military General Staff. Participants were Colonel Miyoshi Yasuyuki, Instructor of Army Staff College, as director of this manoeuvre exercise, and students of Army Aviation as exercise players. Before he wrote the plan, Colonel Kazuo Tanigawa spent nearly one month in 1940 investigating British Malaya, French Indo-China and Thailand for operations against British forces of the southern area. From this experience, he realised the most difficult problem for the execution of this operation was the lack of combat range of Imperial Army fighters. To address this problem, the Imperial Army speeded up the process to adopt the Type 1 fighter (K-43) with a longer combat radius. This new fighter was to have a combat radius of from 600 to 700 kilometres using the same engine as the Imperial Navy Type 0 fighter (A6M). The Type 1 fighter enabled the following: air cover of an anchorage area by fighters, and ‘aerial exterminating action’ to northern Malaya from southern French Indo-China by a strike package of bombers and fighters. Based on using the Type 1 fighter, Tanigawa devised the original plan where a section of ground forces would begin to land in northern Malaya to capture airfields. After ‘aerial exterminating action’, the ground forces’ main body would land in Mersing, in north-east Singapore, with the support carrier group. But Director Miyoshi set the exercise to land at Singora and then go down through the Malay peninsula. He thought Tanigawa’s plan would not guarantee enough control of the air for this operation because he could not count on support from the carrier group at that time. In fact, the Type 1 fighters available for use in the Malaya offensive air operation consisted of only two regiments (60 fighters). The difference in thought came from their operational concept. Tanigawa made much of ‘aerial exterminating action’ at the beginning of a war to gain control of the air. However, Miyoshi considered the long theatre of the Malaya peninsula and instead placed greater importance on ensuring control of the air step by step by gradual advance.
Next is an example of how they actually gained and maintained control of the air in the Malaya offensive air operation. The Imperial Army attached much importance to the speed of offensive action in both the ground and the air operation in Malaya. Imperial Army Aviation perceived that this speed was restricted by the speed of gaining control of the air, and the advance of control of the air was related to the speed of capturing airfields. Imperial Army Aviation adopted tactics to accelerate control of the air by utilising ‘aerial exterminating action’ and capturing airfields for Imperial Army Aviation to use one by one to complement the still-short combat radius of the fighters. In the opening battle that launched this operation, the 5th Division, as advanced elements of the 25th Army, started surprise landings in Singora and Patani. The Takumi Column, commanded by Major-General Takumi Hiroshi, and the Uno Column, led by Colonel Uno Misao, landed in Kota Bharu and Nakhotn, Bandon, before the start of ‘aerial exterminating action’. These landing forces included air section troops such as aircraft maintenance crew, crew for repair and management of airfields, etc. The landing of the Takumi Column was at 2.15 a. m. on 8 December 1941, almost one hour before the attack on Pearl Harbor. ‘Aerial exterminating action’ against the airfields at Sungei Petani and Alor Star in Kedah province began at 8.20 a. m., almost six hours after the Takumi Column landing.
Miyoshi’s plan included a traditional area of conflict in the operational concepts between ground forces and Army Aviation. This conflict was the order of priority between ‘aerial exterminating action’ for gaining control of the air, and the ground support mission. In his plan, the speed of gaining and expanding control of the air would be subject to the speed of the capture of airfields, where the capture of airfields was a ground operation itself. This was the dilemma of Tanikawa. He longed for air operations as an independent ‘air force’ in Malaya.
The endeavor to carry out independent air operations in Malaya
After the map manoeuvre exercise at the Army Staff College, Tanigawa began to devise a full-dress plan of offensive air operations while serving as a staff member of the Army Division of the Imperial General Headquarters from early September 1941. At that time, the ‘Outline of Imperial Policy’ to assume the offensive in the Southern area was decided. At the beginning, the operations area of the Southern area was divided into the Philippines front and the Malaya/Singapore front. After Tanigawa completed the plan, he became the chief of the air staff office at the Southern General Army Headquarters on 13 November 1941. There is evidence showing the essence of Tanigawa’s operational concept as an ‘independent army air force’ in his plan and leadership of the Malaya offensive air operation. This is seen in the concept of ‘independence of aviation units’ and ‘uniqeness of air operations’.
Looking first at ‘independence of aviation units’, Tanigawa tried to gain independence of aviation by giving discretionary powers concerning air operations to the Southern General Army in the Southern offensive campaigns plan of the Army Division of the Imperial General Headquarters. His campaign plan to put whole aviation units under the direct control of the Southern General Army Commander was approved on 5 November. In his plan this operation would initially begin by the landing of advance elements in Malaya and by air attack on the Philippines. Next, major elements of the ground forces would land in the Philippines and Malaya and should quickly capture them based on a successful result of rudimentary air operations. Based on the guidelines of this air operation, Imperial Army Aviation units were expected to gain control of the air by pre-emptive attack on enemy airfields jointly with Imperial Naval air units. This was intended to steer landing operations of major elements to success followed by air support to ground operations. The main body of Imperial Army Aviation advanced to Malaya. The Southern General Army was organised with the 14th Army, primarily consisting of two infantry divisions for the Philippines offensive operation, and the 25th Army of four infantry divisions for Malaya, as the direct control units; and the 3rd Air Corps of three air brigades, the 5th Air Corp of two air brigades and other small air units.
This plan gave priority to the ground support mission, but Tanigawa, as air staff officer of the Southern General Army, took direct control of aviation units to pursue the plan for independent air operations. In the plan of Southern General Army, Tanigawa attached the 5th Air Corps to the Commander of the 14th Army, but he left the 3rd Air Corps under direct control of Southern General Army. By not attaching the 3rd Air Corps to the 25th Army, the organisation of the task force placed the 3rd Air Corps on an equal basis with the 25th Army. In addition, he reinforced the 3rd Air Corps by attaching one air brigade of the 5th Air Corps. The 3rd Air Corps was composed of the 3rd, 7th 10th and 12th Air Brigades. Thus the 3rd Air Corps had a total of 612 aircraft, and was the main force of Imperial Army Aviation. This source of air power was used to capture Malaya as the main air operation of the Southern General Army. The reason for this quantity of aircraft was based on the following estimate. The Imperial Army projected that British Air Force aircraft were around 200 to 250 in Malaya, 200 in India and 50 in Burma. The Imperial Army planned to deploy two or three times that number to achieve superior air power potential in the main theatre.
The issue concerning attachment of air troops was the most difficult and anguishing issue for Tanigawa. He finally came to a conclusion that did not attach air troops to ground forces, but had air troops supporting the ground forces. He had anxiety about the ground forces’ lack of understanding concerning the uniqueness of air operations, and he was furthermore apprehensive about possible obstructions to progress in overall Army operations by the feud within the Imperial Army between ‘aerial exterminating action’ and the ground support mission that had existed since the compilation of ‘Air Troops Operations’. Tanigawa reasoned that the 3rd Air Corps, who supported not only the 25th Army of Malaya but also the 15th Army of Burma, might have a chance to shift the centre of gravity of ‘aerial exterminating action’ depending on the situation. He also felt that the ground forces did not have staff with experience and expertise to fully realise the complex mechanism and operations of air power operations. Above all, Tanigawa feared that lack of understanding by ground forces could bring about an unnecessary loss of valuable and scarce air assets. Tanigawa thought that control of the air by ‘aerial exterminating action’ contributed more to the overall army operation than just providing ground support mission. He tried to plan air operations mainly to gain control of the air under direct control of the Southern General Army, but Tanigawa understood that attachment to ground forces was also favourable for acquiring enemy airfields.
This issue became apparent during the Malaya offensive operation. The 83rd Independent Flying Regiment was to be attached to the 25th Army in the plan, but deployment of this regiment was delayed at the beginning of the operation. Therefore the staff office of the 25th Army was concerned that there was not enough air support for the landing operation of advance elements and requested the attachment of flying units to provide ground support for exclusive use. Thus, emotional disagreements occurred between the 25th Army and the 3rd Air Corps. A certain air staff officer of Imperial General Head-quarters who visited front-line ground forces on 19 December suggested that the 3rd Air Brigade be attached to the 25th Army temporarily. Tanigawa also investigated the situation, and pointed out that Lieutenant-General Tomoyuki Yamashita, Commander of the 25th Army, did not always want the attachment. The misgiving of the 25th Army’s staff office about this attachment came from an incomplete linkage between air and ground operations during the previous week. He observed the essence of this issue as follows. The 25th Army only discussed whether or not flying units directly supported ground forces without considering the profit from gaining control of the air. The staff of the ground forces did not understand the complex mechanism of flying units. Tanigawa eventually refused the request of the 25th Army, and kept the 3rd Air Corps under direct control of Southern General Army to maintain the independence of aviation units.
In the operation plan of the Southern General Army, considering the characteristics of the Southern theatre, Tanigawa gave a free hand to the 3rd Air Corps on air operations under direct control of the Southern General Army, and tried to facilitate the unique nature of air operations without having them being dragged into exclusive ground operations. In the first phase of this operation plan, the mission of the 3rd Air Corps was mainly exterminating enemy air power and supporting the 25th Army’s operation using the 3rd Air Corps major elements. Next the 3rd Air Corps supported the 16th Army in the Southern Sumatra operation by trying to cut enemy communication lines and by strategic bombardment. In the second phase, the mission was supporting the 16th Army in the Javanese theatre by a large number of the 3rd Air Corps elements supporting the 25th Army. Tanigawa gave the 3rd Air Corps the primary mission of exterminating enemy air power. This is because it was impossible for the 3rd Air Corps to be exterminating and supporting at the same time while air and ground operations moved simultaneously in the first phase. It seems that the writing together of exterminating and supporting in the Imperial Army Aviation was only a compromise to the conflicts between aviation and ground forces in Imperial Army. In addition, this air operation was planned to ‘exterminate’ and ‘support’ in the vast theatre from Burma to Java. It seems quite natural and reasonable that gaining control of the air should have been the main mission of this air operation in its contribution to the overall campaign.
For instance, ‘aerial exterminating action’ to Rangoon was executed twice on 23 December during the Malaya operation. This operation was in order to eliminate the enemy air threat and to apply political pressure by air attack to the heart of Burma as British air activities became conspicuous in Burma. But this air operation ended with an unexpected loss because of insufficient co-ordination between bombers and fighters. In another example, the Singapore operation and the Palembang airborne operation were conducted at almost same time. The 3rd Air Corps launched ‘aerial exterminating action’ on Palembang on 6 February 1942, and supported the Singapore landing operation by the 25th Army from 9 February. The fall of the Singapore fortress was 15 December, and the airborne assault on Palembang was 14 December, the previous day. The Commander of the 3rd Air Corps also led paratroops at that time. This shows how Imperial Army Aviation demonstrated the uniqueness of operations through ‘aerial exterminating action’, ground support operations and airborne operations.
Tanigawa developed planning and operational leadership from a perspective of the ‘independence of aviation units’ and the ‘uniqueness of air operations’ in the Malaya offensive operation. It was his goal to execute air operations as an ‘air force’ for gaining control of the air by ‘aerial exterminating action’ during actual combat operations.