Chapter 4: IJA Tactics and Methods
The Imperial Japanese Army was overwhelmingly committed to the primacy of the offensive. They considered the defense to be almost un-Japanese in spirit and practice. The Imperial Japanese Army was though, surprisingly quite aware of its shortcomings in terms of firepower, technology, and material. They did how ever believe that their intangibles could more than offset these deficiencies.
To make our task of discussing Japanese Tactics manageable we will present them in four categories. These four categories are; Theory, Attack, Defend, and Specialized. There are more ways to break it down then this but manageability is important. I opted not to break the categories down into geographic areas because essentially the Japanese viewed jungle fighting as pretty much the same, in regards to operational methods, as open country fighting. I also for the sake of manageability opted to not go into the detailed methods of defense as employed by the IJA in the Pacific Islands. They had various categories for different types of islands though they used a standardized over all defensive scheme which they then applied to each with the needed minor modifications. So a good general overall understanding of Japanese defenses will suffice.
As I already stated the Japanese were fundamentally offensively minded. This offensive attitude held fast even though the Japanese knew that compared to western forces they were seriously deficient in material, resources and firepower. To overcome these deficiencies they would rely on the intangibles and simplicity. The basic concept, which guided all Japanese military actions was that, a simple plan carried through with power and determination coupled with speed of maneuver will so disrupt the plans of hostile forces that success will ensue.
The Japanese believed correctly that they had to strike first, and that they had to strike with the utmost of surprise and that only in this way would they ensure that the campaign would be short and decisive, because they correctly believed and understood that if their enemies were allowed to gather strength, then Japan would lose.
This need for a short, sharp, decisive campaign was further emphasized in Japanese Combat Orders. The most typical ordered result was “the enemy will be annihilated.”
To understand how the Japanese wished to accomplish both their political and military goals we must briefly digress and look at strategy and doctrine. In doing so we must be ever mindful of the Japanese belief in their own inherent moral superiority as a race and people apart.
In this view the Japanese victory of 1905 over the forces of Imperial Russia must be considered. This victory must be considered because it was the first significant victory of an Asian army over a European/western force. The effect this victory had was two fold. On the first side it confirmed in the Japanese consciousness the superiority of their military and by direct extension their culture from which their military came from.
The second was the effect that an Asian victory over a western or European force had for the teeming masses of Asia suffering at length under the colonial rule of the other western powers. Many of these teeming masses looked to Japan’s victory as proof that Asians could secure their own liberation. The Japanese also began to echo this cry of Asia for the Asians.
This manifested itself in the Japanese dangling the bait of liberation from the Europeans/westerners rule before the nationalist movements of Burma, India, and Indonesia. This inevitably lead to the formation, by the Japanese, of the Greater East Asian Co-Prosperity Sphere, which the Japanese subsequently bungled but which did set the stage for the post-war de-colonization movements that later, swept across Asia.
A second significant event, which influenced Japanese strategy, was the experience of the First World War. The Japanese fought on the side of the victors but felt robbed of the fruits of their efforts. The Japanese felt that this was because they were Asians and not white Europeans or westerners.
The experiences of Germany and the Allies in the war also weighed heavily on the mind of Japanese war planners. The collapse of the rear areas and the sweeping communist movements had a dual effect on Japanese war strategy. On the first hand they became bitter opponents of communism and anything, which smelled of communism. This would play a role in their negotiations with the US before the Second World War vis-à-vis how best to deal with Mao and his burgeoning Chinese Communist movement.
Most importantly though was that the Japanese came to believe that modern warfare demanded a nation in arms, a Total war society with the homeland tied equally to the efforts of the front. (See the article on Total War Preparedness by Nicholle Thery-Williams in the WWII Article Section of 1jma.dk). This struggle for Total War Preparedness was a struggle for both resources and political power, which would finally be won on the political front by the militarists only on the very eve of the Second World War.
This quest for Total War Preparedness amongst a nation bereft of natural resources needed for waging modern war was dealt a stinging blow by the worldwide depression of 1929. Their lack of vital natural resources and the depression dictated certain defense policies, which would shape the Japanese forces which would fight the Second World War. The IJA’s reaction to its lack of resources was therefore to focus on what it believed to be its single unique and greatest resource, the spirit of its individual infantryman. To that end they endeavored to ensure that they had the maximum number of highly trained and motivated infantryman that their scant budget would allow. It is also probable that their own cultural biases towards individual valor led both the Army and the Navy to focus on aircraft research and development rather than on other weapons types. After all an airplane more than a tank or battleship more closely resembled and allowed for individual valor and spirit.
With the IJA focusing on maximizing the numbers of its infantry and on aircraft development there was little money left over for tanks or other weapon developments. This did not bother the Japanese greatly as they felt that they could never, given their limited resources, equal the number and quality of weapons the west had, so it was better to focus on what they believed was their own unique and unmatchable strength.
This lead to the Army focusing on the primacy of their infantry, a force, they were sure that the west could not match. In keeping with their belief in the supremacy of the offensive, shock action was viewed as more important than firepower. This desire to maintain the strength of their infantry on a limited budget, lead to the conversion of Japanese Infantry Divisions from the square concept to the triangular. This increased the overall number of infantry divisions available and allowed for a more aggressive us of available forces. They envisioned the triangular division as having one sub-unit for a holding attack, one sub-unit for a flanking envelopment attack, and the last sub-unit as an exploitation force. Whereas the square division had focused on firepower the new triangular division fit the strategy of maneuvering quickly and destroying the enemy.
At both the strategic and the tactical level this caused the Japanese commanders to reach attack decisions when a more orthodox commander would have chosen another approach. Thus it was, that the Japanese opted for war with the west in September – November of 1941. They viewed their choices as; do nothing and be unable to fight later, hope for a negotiated settlement from an ever dwindling position of strength, or to risk war now and be able to negotiate with a defeated and dispirited foe. At the highest levels the Japanese knew they could not win a long war. They decided to attack while they still had a chance for victory. This logic is a continuing pattern, which colors Japanese actions at the tactical levels through out the war.
At the tactical level the Japanese recognized the following types of attack: the meeting engagement, the hasty attack, the deliberate attack, and the pursuit.
The preferred form of maneuver within each of these attacks was the envelopment with regulations giving the usual admonishments against costly frontal attacks. Though a frontal holding attack was still considered a valid aspect of any envelopment.
Even though the regulations strongly admonished against frontal attacks they did admit that at times when hesitation would allow the enemy to either improve his defenses or reinforce his position before significant Japanese forces would arrive, it may be better to attack straight in with vigor in order to gain or retain the initiative, even with out the normal levels of support for the attack.
The Meeting Engagement:
The meeting engagement was the foundation of all Japanese tactical training. It was given the most ink in regulations and the greatest emphasis in map training exercises. The Japanese defined a meeting engagement as a collision of two hostile and moving forces. Commanders were encouraged to fight a meeting engagement with swift and decisive decisions and executions so as to seize and retain the initiative, seize key terrain, by employing bold independent action of subordinates and energetic leadership.
The advance to a meeting engagement followed the same general practices of other armies at the time though with a decided preference for advances in two parallel columns.
In the advance the Japanese made extensive use of an advanced guard formation, allocating up to one third of available strength to this force. The advance guard was also under the direct command of the over all commander. The primary mission of this formation during the advance was to seize key terrain, destroy road nets vital to the enemy, and to launch surprise attacks on enemy units found to be still in march formation.
Advanced guard formations showed a strong tendency for bold, quick actions. In its reconnaissance operations it relied most heavily on map terrain recce and the regulations for its usage warned about “waiting for overdeveloped intelligence before deciding to act” Surprisingly the usual time allowed for recce was only about one and a half hours.
Once the advanced guard had located the enemy, the main body would be committed to the meeting engagement. There were two methods for committing the main body, piecemeal and coordinated. Though the coordinated deployment was the schoolhouse preferred method, more often then not it was the piecemeal commitment, which was employed due to the obsessive desire for swift and decisive action.
The deployment of the main body was covered by available artillery, which typically sought a forward and centered location so that it could cover the maximum amount of area laterally and in depth without having to re-deploy. The mission of the covering artillery force was three phased. The first phase was to cover the deployment of the infantry itself. This was followed by close support of the infantry attack and finally by attempting to seal off all avenues of retreat or reinforcement to the enemy position which was being attacked.
The deploying infantry did not pass into assembly areas prior to the attack, rather they went into the attack directly from the march after receiving usually verbal and very fragmentary orders. The attack frontages assigned to the infantry were very narrow by the standard of the day with a regiment conducting a holding attack being allocated 3000-4000 meters and a regiment conducting the main effort being given just 1600-2200 meters. They would be supported by artillery, which was usually located just 600-1500 meters from the line of departure (LOD) and backed up by the reserves that would hover back at 1200-2200 meters, with the supply trains back at 8800-11000 from the LOD.
In a typical meeting engagement the foe of the Japanese could expect sharp and aggressive attacks to the front, against key terrain features, and a flanking attack, which had the goal of cutting up the enemy into small bite, sized pockets much like a Finnish motti attack.
These flanking attacks were typically of platoon or company in size with
each sub group given a specific objective. These envelopments would be
led by scouts traveling 350 meters in front of their units and could be
as wide as two miles and as deep as six miles. The heavier machine guns
were generally kept well forward and worked in pairs. An enveloping platoon
on contact with the enemy would typically commit two of its rifle squads
to a holding action, deploy its mortar squad behind and center and send
its remaining squad on an envelopment of its own. Should the sweeping
element encounter an enemy unit attempting to envelop them they would
typically go to ground and hold their fire until the enemy had passed
over and through them and then turn and take the enemy in the rear or
A deliberate Japanese attack was characterized by speed and simplicity. It was not improbable for an attack to be made with in 12 hours of locating a prepared enemy position. The Japanese felt that a rapid attack would prevent the position from becoming even harder to attack later if the enemy was allowed time to improve and reinforce his position at will. The attack order would designate the sectors to be attacked as left, center, and right with one of these wings being given the status of main effort.
Typically you could expect the attack to occur at night. In fact since their success in night operations in 1905 the Japanese had come to the conclusion that the night attack was the traditional form of Japanese attack. There was even a training slogan, which brayed, “The night is worth a million reinforcements.” The regulations go on to say that a night attack is especially useful when the enemy defenses are strongly organized; the enemy is so numerous as to make a daylight attack unprofitable. The regulations further stated that a night attack could be used to continue success gained in the daytime, as a deception prior to a day light attack, to prevent an enemy nocturnal withdrawal or most importantly to mitigate an enemy superiority in firepower.
These attacks would usually begin with aggressive and constant recce attacks by probes and infiltration. Normally engineers moving forward to cut wire and reduce obstacles would follow these probing attacks. The Japanese assumed that any enemy position would be covered by wire. Typically three lanes cut through the wire were considered sufficient for a battalion sized attack force to go through. Once the lanes had been cut the first wave of attackers would move forward with out artillery support relying on stealth to push in the enemy out post line. This first wave was generally a two companies in strength. Once they were in the out post line they would be followed by the second wave of two companies minus one platoon which would be held in reserve. Typically every Japanese unit from company and up would maintain some sort of reserve. The waves would move forward with groups of one or two platoons each assigned very specific objectives to take. The normal depth of a night attack was 1100 meters behind the enemy front line these attacks were characterized by their lack of artillery support, ambitious objectives and dense attack formations. They attempted to secure their objectives before first light so that any enemy counter attack would have to be done during daylight. To aid their attacks the Japanese showed a marked preference for attacking up hill so that he enemy would be silhouetted on the skyline.
In the event that the attack was to occur during daylight the defender could expect the following. The Japanese LOD would be about 550-2200 meters from your forward positions with the objective of the Japanese attack being the rear of your artillery positions. The attack would mostly hit you at daybreak only four hours after the troops had been given their orders to attack and annihilate you.
The enemy troops would crawl towards you not firing their weapons until they were close enough to lunge at you with the bayonet. There are examples from the invasion of Malaya of crawling Japanese troops using their helmets to, mole like, push the earth up in front of them until they were close enough to use the bayonet.
In the wing of the main effort they would advance on narrow frontages to ensure success. Typically a Japanese Company would attack in a zone only 225 meters wide, a Battalion 400-600 meters, and a Regiment 1100 meters. In the other non-main effort wings the attack frontages would be 20-25% wider. He reserves would be located only 3000 meters behind the main attack.
It would not be uncommon to find tanks attached to the main attack. The Japanese regarded tanks as primarily infantry support weapons. And even after the success of the German Blitzkrieg, Japanese Tank regulations still spoke in broad generalities. Because of their belief that tanks were infantry support vehicles they were slow to develop mass armored formations preferring to create lots of small independent formations for attachment to infantry units. In general Japanese tankers were highly trained, especially in night operations though they tended to be unusually obsessed with the attack and would often dismount their vehicles to attack on foot. During an attack their primary missions were to breach wire and reduce obstacles. The accompanying infantry were trained to press forward even if the tanks were destroyed or held up.
Each wing of the attack would be supported by one or two battalions of artillery who would typically fire a one and a half hour prepatory barrage. Though in keeping with Japanese concepts that artillery is best used as a direct support weapon it was not uncommon to put a battery of guns directly under the command of an attacking infantry company. The barrage would follow this schedule. The first half hour would be for ranging and adjustment, then thirty minutes of wire cutting, followed by thirty minutes of firing on the enemy out post positions. The guns would normally be located in the center of each wing and 500-800 meters from the front line so that they could maintain a constant fire throughout the attack with out having to move to other positions. The normal caliber of this supporting artillery was 70-75mm and they would each have been allocated 900 rounds of ammunition for the attack versus their daily fire allowance of 300 rounds. Japanese artillery showed a preference for direct fire missions though they usually had two or three aircraft assigned for spotter missions.
A battalion of anti-aircraft weapons usually located some 2700-3000 meters in back of the LOD further supported the attack.
Cavalry was usually parceled out to the wings in allotments of one or two platoon to act as messengers. They would travel between command posts located as follows: Infantry Regiments 1100 meters from the enemy, artillery 2700 meters, and the Division command post at 2700 meters from the front. In the area of 1600-2200 meters behind the center of each wing were the first dressing stations and further back, 2500-4000 meters were two field hospitals.
In general the Japanese plan would have been focused on securing its objectives without regard to casualties. The plan would have been bold, incorporating elements of surprise and deception, though with scant time given to conduct an adequate recce. Though dismal in the weight of supporting artillery fire they would not have typically attacked until all enemy airfield in the area had been effectively interdicted.
The conduct of pursuit operations followed the pattern of most armies of the period though there was a marked focus on the total annihilation of the enemy through the use of vigorous and aggressive action by subordinate commanders.
Rivers and Coastlines:
Japanese river crossing operations differed from conventional theory only in that instead of attaching engineers to the crossing units the engineers were centralized for a greater concentrated effort at the crossing site.
As to landing operations, it is suffice to say that the Japanese sought always to conduct landings rather than assaults. Stealth and surprise were the virtues sought.
Japanese airborne operations were noted for their small size and diversionary purposes. There are instances of troops jumping into a theater of action for the purpose of linking up with fifth columnists but that seemed to be the exception rather than the rule.
The Japanese did posses chemical warfare weaponry. They did in fact employ gas weapons in some operations in China in 1941. There were also isolated instance of localized use of gas weapons in Burma. The Japanese were terrified of an Allied chemical response and therefore opted not to use these weapons as policy. As noted above; several times they were used by local commanders against the prevailing wishes of the High Command.
Japanese anti-tank tactics relied on an elastic defense. It was not characterized by the rigidity of their normative defensive methods but rather sought to attack enemy tanks some 800-1500 meters behind the out post line by means of obstacles, anti-tank guns and tank hunting squads equipped with incendiary grenades and demolition charges. The available anti-tank guns and obstacles were usually set up on ground, which was the most likely avenue of approach. The obstacle plan emphasized using obstacles to force enemy tanks into kill zones for the guns, in ground which tanks will have difficulty traversing. A few guns will be further back to deal with penetrations, which threaten Japanese artillery. The Japanese placed great stock in digging in and sitting guns rather than on maneuvering them. Normally each platoon in the MLR would designate one of its squads for tank hunting duty and allocates large amounts of smoke grenades to its members to aid in that process. During the smoke and confusion some artillery will be brought up if the situation warrants it to conduct direct lay fire missions against tanks. The primary weapon however, given the relative weakness of Japanese anti-tank guns, remained the motivated and determined tank hunter.
Being inclined by cultural reasons and tactical imperatives to the offensive the Japanese considered the defense distasteful and un-Japanese in spirit. Very little ink was given in Japanese regulations to the conduct of defensive operations. In fact those map exercises covering defensive problems were constructed so as to make the attack not an option, placing the commander already in the defense with orders to conduct defensive operations though with the intent to transition to the attack as quickly as possible through the auspices of an aggressive and active defense posture.
Japanese defensive operations were based on a Main Line of Resistance (MLR) guarded by a series of outposts. Generally the Japanese made excellent use of terrain in locating the positions of their MLR, though they showed a marked tendency to avoid depressions as it was felt that in the event of a gas attack the gas vapors would settle into the low ground making their continued occupation unmanageable.
The defense was laid out by assigning left and right wing sectors and available cavalry forces would cover the deployment. The positions were set up usually for all around defense both in the lay out of units and the construction of individual positions. An infantry battalion would normally be assigned a defensive sector with a frontage of 800-2000 meters, positioning its reserves some 700-1500 meters back to add depth and an all around nature to the sector it was to defend. These defensive positions were further characterized by their forward deployment of heavy machine guns set up to provide interlocking flanking fire. In direct contrast to standard western methods of firing to the front the usual Japanese method was to fire to the flank providing interlocking fire to the front of a neighboring position.
In front of the MLR was the out post line. This was typically located 1500-3000 meters in front of the MLR. The out post line was characterized by aggressive patrolling and had the missions of; preventing the enemy from gaining surprise against the MLR, and forcing the enemy to commit an early deployment of his attack formations thus slowing down the momentum of his attack. An infantry division would normally assign one or two battalions to serve in the outpost line and these troops would then assume the role of the divisional reserve once they had fallen back through the MLR. Their new reserve positions would be located some 5000-6000 meters to the rear of the MLR. They would be collocated there with any tanks that had been assigned to the division.
The MLR itself was comprised of a series of strong points organized for all around defense rather than occupying a contiguous line of troops. These strong points were quite well constructed and sited to typically project above the surrounding terrain only a meter. Three hours being the minimum time needed for a standard rifle squad to construct a 25meter long standing trench. In general every attempt was made to blend them into the local landscape and camouflage them. The quality of their construction was uniformly excellent with thick overhead cover. It was not uncommon for the Japanese to call down friendly mortar fire on top of these positions when the enemy was found to be crawling all over them. Every attempt was made to construct these positions on reverse slopes or high ground.
Because of the constant inculcation of the need, and primacy, of the attack Japanese soldiers would often leave the protection of their bunkers to meet the attackers with bayonets in front of their positions. Though when they did choose to use fire instead of shock they would generally hold their initial fire until the enemy was with in ten meters of their positions or if the enemy had not detected them they would let the enemy pass through and take them from the rear. The Japanese infantry also, because of their attack first mindset, would not hesitate to launch immediate counter attacks by any and all available forces, often in a pell-mell approach believing that by the vigorous application of shock action they could so disrupt the enemy attack and turn their local counter attack in to a full scale Japanese offensive. In the event that these troops were caught in the open by enemy fire you could expect the Japanese to inch forward adopting hugging tactics to minimize their losses.
Behind the MLR was located the artillery positions. These were arrayed in a zone 1700-2200 meters behind the MLR but in front of the divisional command post, which was located 5500 meters to the rear of the MLR. Regimental command posts were much closer to the front being only 1300 meters behind the MLR with available cavalry assigned to patrol the flanks of the positions.
The Japanese viewed retreats and withdrawals as totally un-Japanese in character and when they did conduct them they were usually labeled as advances to a strategic location. During these “advances” they would constantly look for any opportunity to turn back to an attack rather than to fight a normal delaying action. A further characteristic of these “advances” was that the rear guards covering the “advance” was usually made up of machine gun teams who would be sacrificed for the safety of the entire force.
Over all Japanese defensive methods were noted for their rigidity and
willingness to die in place rather than live to fight another day.