A report on Japanese offensive doctrine and tactics in WWII, from Tactical and Technical Trends, No. 32, August 26, 1943. [DISCLAIMER: The following text is taken from the U.S. War Department publication Tactical and Technical Trends. As with all wartime intelligence information, data may be incomplete or inaccurate. No attempt has been made to update or correct the text. Any views or opinions expressed do not necessarily represent those of the website.]

JAPANESE OFFENSIVE TACTICS Japanese tactical doctrine has always stressed the superiority of the offensive. The following summary of recent Japanese offensive tactics together with the specific example indicated, are taken from a British publication. *          *          * a. Envelopment In the past envelopment in Japanese tactics has always been closely identified with attack. Attack by single or double flank envelopment is a favorite Japanese tactic. In fact, a study of Japanese offensive operations indicates that envelopment is sometimes used as if it were an end in itself. By placing bodies of troops across the enemy line of communications the Japanese attempt to compel their opponents either to attack them or withdraw, even when other types of attack would appear to promise better results. Japanese strategy and major tactics in the offense against well-equipped forces offer the defender two alternatives--to attack the Japanese often on ground favorable to the defense, or to give up ground. In the first Burma campaign, from the time that the Japanese crossed the Salween River at Moulmein until the last action at Shwegyin on the Chindwin there are very few recorded instances of deliberate attacks. Rather was their superior mobility used to force us [the British] to attack troops who had succeeded in occupying a position behind us. The Japanese chose an area on the line of communication to hold which would cause us the maximum embarrassment and the focal point of the battle which ensued was often a road block. In fact, the Japanese fought defensively in country peculiarly suited to the defense. One big exception to this method during the first Burma campaign was an attack launched against one of our regiments at Kyaukse; here the Japanese suffered considerable losses and the attack failed completely. b. Attack in Mobile Warfare (1) Reconnaissance Japanese attacks are preceded by careful reconnaissance in which various ruses are employed in order to discover the location and extent of enemy localities. Trees are shaken in order to draw fire, defending troops are addressed in their own language in the hope that they will respond, and small parties are used as bait for enemy fire. Finally, it cover permits, scouts may be left in observation for long periods close to the enemy main line of resistance. (2) Methods of Attack Attacks may take the form of single or double envelopment or frontal assaults. Zero hour is often any time from midnight to first light. Between 0300 and 0400 has recently (April 1943) been a common zero hour. (a) The Enveloping or Flank Attack Pressure is exerted frontally while the main effort is made around one or both flanks. Attacks of this nature often involve a double envelopment, a small flanking attack being made with an objective one to three thousand yards behind the enemy's main line of resistance, while a further turning movement is made some miles behind them. This double attack has sometimes been described as two thrusts--one made against regimental headquarters and the other against divisional headquarters. (b) The Frontal Attack While in Malaya and Burma we have chiefly experienced the attack by envelopment, the Americans report that in the Southwest Pacific area frontal attacks have often been made, particularly when an operation demanding more time might have given the defenders the opportunity to improve their positions. Before a frontal attack, every effort is made by reconnaissance and ruses to locate a soft spot. Against this is directed the main effort of the attack, the object of which is to achieve a breakthrough. Forward troops infiltrate, taking advantage of all available cover to creep forward. This is in the nature of a battle reconnaissance which goes to ground when held up by the defender's fire, but brings light machine-gun and mortar fire to bear on any positions it has discovered. If the attack on the chosen sector does not succeed it is not uncommon for the main effort to be directed temporarily against another part of the front--the old axis of attack being reverted to later. (3) Artillery The artillery available for the support of a Japanese division in the attack in mobile operations has, by Western standards, so far been inadequate, and this weakness may account both for frontal attacks being launched without covering fire, and for the words "rash and costly" with which an American commentator describes them. The field artillery so far met with in mobile warfare--and this was largely artillery from the infantry regimental gun company--was chiefly directed against our own gun positions. Such counter battery work in the Arakan has so far been inaccurate and therefore ineffective. Given sufficient data the Japs fire on large and small unit headquarters. c. Attack Against a Fortified Position The predominant considerations in an attack on a fortified position are surprise, preparation, and concentration. The Japanese ability to achieve surprise extends to all forms of warfare. Their preparations for an attack of this nature are extremely thorough and in the case of Hong Kong may be said to have extended over a number of years. Where possible, consular staffs, spies, and even officers and men in disguise have been employed in peacetime to make accurate and comprehensive surveys of fixed defenses and vital communications, while fifth columnists are employed for the same purpose in war. Besides the study of defenses and communications, preparation includes the accumulation of engineer equipment of suitable size to bridge probable demolitions, and the selection and training of special assault troops who have been chosen for their high intelligence. They have been quick to profit by German methods and German experience and to realize that daring and highly-skilled assault troops will succeed where no amount of massed infantry will avail. The operation frequently begins with heavy air attacks on airfields, antiaircraft gun positions and headquarters. Later high-level and dive-bombing attacks are directed against fortifications. A heavy preponderance of artillery is employed and mobile medium artillery (105 mm) firing armor-piercing shells is used against splinter-proof shelters. The technique of the assault is ably described by an officer who was in the battle of Hong Kong: "Numbers of assault troops would infiltrate through our lines under cover of darkness, and would hide in trees and bushes whence they would snipe our troops from the rear. "The position to be attacked would be subjected to very heavy dive-bombing and artillery fire during the day. "Assault troops in parties of ten would stalk the position, making such good use of ground and cover that they were rarely seen. The position, meanwhile, would be subjected to intense mortar fire, and fire from 50-caliber machine guns to penetrate the iron doors and windows of concrete shelters and pillboxes. "When all parties of assault troops were in position in the dark, the mortar fire would suddenly increase. Then the parties of assault troops would make a coordinated assault on the position, throwing hand grenades and firing light machine guns, and at the same time receiving supporting fire from light automatic weapons and machine guns. "If our troops took cover in their concrete shelters, the storm troops would surround the position, and approaching from the rear would drop hand grenades down the air vents of the shelters, killing the garrison; anyone trying to escape from a shelter, was picked off by someone waiting with a light machine gun to receive him." d. Example of Offensive Tactics in the Arakan Early in February 1943 the Japanese were on the defensive in the Arakan sector on the west coast of Burma roughly west of Mandalay. They had withdrawn from the line Buthedaung--Maungdaw, and were occupying positions along the general line Myohaung--Rathedaung--Donbaik (see figure 1). In the Kaladan Valley the opposing forces were not in contact with each other. During the early hours of 21 February, a Japanese force estimated at between 200 and 300, advancing from the East, attacked our small post at Kaladan, the garrison of which withdrew to Paletwa (15 miles north of Kaladan). The enemy at once set about putting Kaladan in a state of defense with the apparent intention of holding any force which attempted to advance southwards down the valley. During the second half of February a steady increase in the garrison at Myohaung was reported and towards the end of the month the Japanese who had previously been singularly inactive in the Rathedaung area began to infiltrate around our left flank by way of the foothills northeast of Rathedaung. On 6 March enemy forces attacked our detachments in the Apaukwa--Kanzauk area. Our troops, an infantry battalion and some gunners, were forced to withdraw northwards up the Pi Valley, during the night of 8 and 9 March and the days following. By now pressure was increasing on the left and right flanks of our force before Rathedaung and by the 12th, when considerable enemy forces from the Kaladan had begun to debouch from the hills into the Mayu River valley, heavy fighting developed east and southeast of Htizwe, the enemy being described by one observer as "coming on in droves." One company of the 1st Punjab Regiment was attacked six times in four and a half hours but held its ground, inflicting heavy casualties upon the enemy. Before descending into the plain the Kaladan force was joined by a battalion from the Tawbya. The combined force fanned out on reaching the plain, not only cutting the line of communications of our force north of Rathedaung but also advancing up the east bank of the Mayu River towards Taungmaw (see figure 2). On the night of March 16-17 our forces, no longer possessing a line of communications, broke contact with the enemy and withdrew northwards through a covering force. The enemy opposite Taungmaw appeared to be in the nature of a holding force similar to that established at Kaladan. The main thrust was continued westward across the Mayu and by March 25 infiltration into the Mayu Range had already begun. At midnight on the 2d and 3d April a party of Japanese suddenly attacked and overwhelmed a standing patrol on a bridge northeast of Indin; they were unable to establish a successful road block but the threat to our communications here and further north was such, that we were forced to withdraw our forces northwards up the coast (see figure 3). From Kanzauk, where this enveloping movement began, to Indin where it reached the coast, is, as the crow flies, a distance of 25 miles, but this actual distance gives little indication of the difficulties which faced the enveloping troops. Except for small paths running east and west through the hill areas all lines of communication run north and south, and until such time as British forces in the Rathedaung area were forced to withdraw, the enemy depended to a large extent for supply on what they carried with them. Later, supply was based on the Mayu River valley but here also it was not too easy, for the British air force and Burmese gunboats continued to patrol the river. As the forces involved in the operation increased, so did the problem of supply. The operation was typical of Japanese offensive tactics: although the maneuver gradually extended right across our front--or rather rear--few direct attacks took place after the battle around Htizwe. A part of the enveloping force occupied a position around Indin and waited to be attacked, while other elements continued infiltration northwards through the hills. At Rathedaung a double envelopment was made, a small force occupying a position near the east bank of the Mayu river about 3,000 yards behind our main line of resistance while the main thrust came in against our left rear, east of Htizwe. As we have observed before, actual attacks as opposed to enveloping movements were made with great determination but they lacked preparation and careful coordination. As a result they were very costly and it is estimated that by the time they reached Indin battalions averaged only 450 strong. (The battalions used in this operation contained only 3 companies and had a full strength of about 750). In conclusion it remains only to be said that once again the Japanese had, where possible, avoided attack as a means of achieving their object using their superior mobility to occupy a position on our line of communications where we should be compelled to attack them or withdraw.

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