Between December 1941 and early 1942, while Japan made its lightning conquest of Southeast Asia and the western Pacific, its navy and army appeared invincible to the Allies. Indeed, the Japanese victories owed themselves largely to skilful planning, along with the tactical and technological efficiency of their armed forces. The weak state of the US and British Empire also played an important part in facilitating Japan’s successes. Yet, as early as March 1942, the high command had to contend with many of the weaknesses which plagued its war machine, the most important of which was that neither the IJN nor IJA had the capacity to defeat the Western powers in a prolonged conflict. The Imperial forces were overstretched, and America had not been knocked out of the war. On the contrary, the US was preparing to strike back, and most importantly, it possessed the industrial resources to build a military force that was far superior to anything the Japanese could deploy. Yet the military leadership failed to comprehend the predicament it faced, and maintained that Japan could deal a crippling blow on its opponents and thereafter secure its conquests against enemy invasions. The misperception led the Japanese to embark on a number of failed ventures in the Indian Ocean and Pacific areas which eventually culminated with the IJN’s defeat at Midway in June 1942. The latter encounter was arguably the single battle which turned the tide of the war in the Allies’ favor, and emasculated Japan’s capacity to conduct further territorial conquests.
Reasons for Japanese Successes
The success achieved by the Imperial navy and army in securing control over an area stretching thousands of miles from Burma, all the way through the East Indies to the islands of the Pacific, in such a short period of time can be attributed to effective strategic and operational planning on the part of the high command, coupled with the fighting skill of the Japanese forces at the battlefront level. In addition, the poor level of preparedness which the Allied defenders demonstrated in areas such as Malaya and the Philippines played a distinct role in helping the invaders.
At the strategic and operational levels, the Japanese succeeded primarily because the navy managed to attain complete command over both the sea and airspace in the areas they intended to conquer. Furthermore, the IJN made good use of its limited strength by concentrating on key positions in the western Pacific. Throughout the period prior to the war, the navy strived to develop a way to optimize its resources. Commanders realized that a numerically inferior fleet had to rely on the element of surprise if it was to have any prospect of defeating its opponents, and focused on commencing wars with a preemptive strike. The idea was to destroy the American fleet before it could threaten Japan’s home waters. Indeed, the Pearl Harbor operation was among the most notable examples of how the attacking side could use secrecy and deception to catch the defenders off guard and inflict a devastating blow. With the navy able to achieve supremacy over the Pacific regions, the IJA could be assured that transports were able to carry troops to the areas of operations without facing any significant Allied interference. The army was also supported by a secure supply line which stretched back to the home islands. This meant that once onshore, troops received a steady flow of reinforcements and equipment to sustain their advance.
Japanese operational planning was also helped by an efficient intelligence network. For example, Colonel Tsuji Masanobu, chief of the Twenty-fifth Army’s operations staff, recalled how his officers conducted a detailed survey of the landing beaches in Malaya, and meticulously verified the possible routes for the inland advance. Japanese agents also carried out sabotage operations, destroying installations such as air bases, oilfields, and railway lines in a systematic manner. Equally impressive were their subversive activities. Winning the hearts and minds of the indigenous people in Southeast Asia had been a key objective for years. By the time the war broke out, the intelligence services had forged connections with key leaders of the Nationalist movements in most of the European colonies, and extensively spread anti-Western propaganda to the local population. As a result, the invasion received widespread local support. When the Imperial army entered the East Indies and Philippines, the colonial administrations collapsed almost overnight. In Malaya, thousands of Indian troops deserted the British army, and joined forces with the conquerors.
The Imperial forces also successfully devised tactics and weapons which enabled them to out-maneuver their opponents. In particular, the navy demonstrated how it had made a fruitful effort to develop the fighting capacity to secure control over the western Pacific areas. The Japanese sought to circumvent the disadvantages arising from their inability to match Western levels of ship construction, by building vessels with greater firepower and endurance. By the late 1920s, technicians and engineers had developed a number of sophisticated armaments that placed the IJN in a good position to compete with its US and British rivals. Battleships and cruisers were fitted with guns and torpedoes that outranged most of their opponents, as well as larger propulsion systems to increase their velocity and cruising radius. 6 In order to enable gun crews to deliver accurate fire, control towers were constructed with extra elevation so that they could house various pieces of equipment such as range finders, searchlight directors and firing calculators. Officers in the bridge were also able to locate their targets from a longer range. Naval ordnance performed well. The long-lance was the most advanced torpedo to be constructed for the duration of the conflict, and could hit targets up to 10,000 yards away at a speed of 45 knots. Torpedoes were also oxygen-propelled, which meant that they did not produce a wake, thereby rendering them difficult to detect. In the area of tactics, the Imperial fleet developed innovative ways of using modern technologies. Crews were adept at conducting night operations. This was an aspect which most navies, including the British and Americans, had neglected, mainly because maneuvers under the cover of darkness were deemed to be too complicated. Radio silence was also maintained in order to avoid revealing the ships’ positions. The Japanese fleet’s advantages became fully apparent at the Battle of the Java Sea, when they frequently managed to locate and sink Allied forces before the latter could react.
The IJN also made a painstaking effort to build up its air power. Under the 1937 fleet replenishment program, the 25,000 ton carriers, Shokaku and Zuikaku, were constructed. In the same year, the navy air staff established the specifications for the Zero fighter, which was designed to fly with greater range, speed, and maneuverability than any rival interceptor. Mitsubishi was commissioned to construct the new fighter, and by September 1940, the first completed machine entered service in China. As a result, the Japanese were able to attain control over the skies in the areas where they conquered, and eliminate their opponents’ air forces. Bombardment operations were also carried out effectively. Aircraft manufacturers assembled a number of bomber types which launched torpedo and aerial attacks with a high level of accuracy. Naval pilots in particular were well trained, and demonstrated their capacity to take out enemy vessels both in port as well as in the open sea. The sinking of the British capital ships Prince of Wales and Repulse off the coast of Malaya demonstrated the skill and accuracy of Japanese bombardment techniques. Aircrews often used several types of maneuvers in conjunction in an effort to overwhelm the defenders. Horizontal bombers initiated the raid, attracting the attention of anti-aircraft crews. Torpedo planes and dive bombers then followed, and were often able to operate without interference. Pilots pressed home their raids, even when they faced opposition. The result was often a highly efficient bombing pattern. The naval air service also provided support for the amphibious operations in the Dutch East Indies and Malaya, with good results. Flying boats conducted reconnaissance missions, while heavy air attacks were launched to take out communications facilities and coastal defense batteries. In order to achieve air superiority over the vicinity of the landing beaches and thus protect the landing parties from aerial opposition, the Japanese undertook to neutralize the nearby aerodromes.
Although the Imperial army was not as technologically advanced as the navy, its tactics nevertheless showed finesse. The most decisive advantage was the maneuverability and fighting skill of Japanese infantry units. In the area of amphibious operations, landing parties rarely faced troubles in securing a foothold on their objectives. The Japanese developed suitable equipment, including landing craft with hinged bows that allowed the quick unloading of troops and supplies. In Malaya, amphibious forces often chose beaches which the defending forces had considered unsuitable for landings, owing to the steep gradient and choppy tidewater. Adverse terrain and weather were not an obstacle, and on the contrary, the Japanese deliberately carried out their operations in such conditions so that they could appear where their opponents least expected an attack. The army also proved adept at conducting overland advances, particularly in the jungle terrain which prevailed in the Far East. Troops did not depend on motorized transport, and could overcome any natural feature, including hills, wooded country, and river crossings. By doing so, the attackers circumvented the main roads, where Allied forces had concentrated their defenses. Within days after the landing at Malaya, the IJA’s skilful outflanking moves left British forces with few choices apart from withdrawing and consolidating themselves in more tenable positions at the southern portion of the peninsula. The Japanese also regularly infiltrated their enemy’s positions. In the Philippines, small parties often broke through the gaps in the US army’s lines, remaining silent, and waited for reinforcements to arrive until a sufficient force was gathered to launch a small assault. Firecrackers and other types of ruses were then set off to confuse the defending troops over the location of the attacking force. Thereafter, the invaders overwhelmed the disoriented American soldiers by launching a full-scale advance. The Imperial army was also aided by the strong morale which prevailed within its rank and file. Troops conducted their advances with little concern for losses, and demonstrated an unquestioned dedication towards their organization. Lieutenant-General Hutton, who commanded the British forces in Burma, noted that the fundamental cause for the Japanese success was the extent to which soldiers had been imbued with an “offensive spirit.”
Finally, the Imperial forces were aided because the defending Allied forces were in a weak state. In regard to naval and air forces, the British and Americans not only lacked adequate strengths, but were poorly equipped and inefficiently trained. Part of the problem was that Western personnel held condescending views of the Japanese, and thought that the latter were incapable of putting up a serious contest. A more serious problem stemmed from the fact that the bulk of the Allied navies and air services were committed to the Atlantic theater, which meant the Pacific areas could not be defended with large forces. The most scathing criticisms, however, were directed at the armies. In many cases, the Americans and British outnumbered the Japanese, but lacked the tactical skill to forestall the invaders. Troops were inept at fighting in undeveloped country. In order to ensure that their positions could be defended, soldiers had to adopt more imaginative methods. Many British army officers conceded that their traditional procedures of employing fixed defenses were unlikely to work if the positions could be bypassed and were not held with adequate strength. Defending forces needed to conduct an aggressive patrol of their surroundings, and in situations where difficult terrain restricted the use of motorized transport, the proper deployment of foot soldiers was vital.
Allied commanders also conceded that their failures were due to a prevailing lack of discipline. A US officer who served in the Philippines noted how the morale of troops was unsatisfactory, and insisted that soldiers needed to undergo a “spiritual training” along the lines of the Japanese, in order to develop a more aggressive attitude. Likewise, General Pownall pondered how British troops were overly dependent on creature comforts and held an aversion to strenuous work, both of which gave rise to a situation where training was conducted without preparing troops for battle conditions. Western personnel who lacked the fortitude to fight in the trying conditions which prevailed in the jungles of Southeast Asia and the islands of the western Pacific were simply no match for the efficiently trained Japanese army, whose troops held a high level of stamina.