Chapter VII

TACTICS OF THE JAPANESE ARMY Introduction The basic tactical principles of the Japanese Army have been carefully developed from studies of foreign army techniques and its own valuable experiences gained in combat under varying conditions. Japanese forces have fought against regular military organizations of several first-class nations and have had considerable experience in combating the constant harassing action of guerrillas on supply lines and rear areas. They have engaged in tank actions on the plains of Manchuria and in mountain battles in Central and Southern China; they have conducted landing operations under varying conditions of terrain and climate. They have been highly successful in their earlier jungle operations, on terrain where good roads and railroads are practically unknown, and where every type of natural obstacle exists. They are not merely jungle fighters, however, for much of their success has been on terrain where principles of open warfare have been applied effectively. By studying the areas over which they expected to operate they effectively organized, trained, and equipped their forces and evolved techniques designed in each case to fit the terrain and meet the logistical requirements peculiar to their own army. The Japanese lay great stress on offensive actions, surprise, and rapidity of movement, with all commanders and staffs operating well forward in order to keep themselves constantly informed of the situation. Their tactical doctrine is based on the principle 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. Combat orders, in both attack and defense, from the highest to the lowest unit, generally carry the admonition that the "enemy forces will be annihilated." Surprise is an ever present element, while the envelopment is the preferred form of attack. Thorough reconnaissance also is taught, and the practice of infiltration is greatly stressed. The Japanese willingness to attack a position with forces which other nations would consider insufficient for the task, is based on the assumption of their so-called military superiority. An explanation of thi assumption calls for an analysis of Japanese psychology, national vanity, and past military successes, which is beyond the scope of this study. To the Japanese officer, considerations of "face" and "toughness" are most important, and they are therefore prone to indulgence in "paper" heroics. They have evinced boldness against poorly equipped troops; however, against first-class, well-equipped forces, it may be expected that they will adopt more circumspect methods. Despite the opportunities presented during 6 years of active combat, the Japanese have continued to violate certain fundamental principles of accepted tactics and technique. Their tendency to persist in such violations is based primarily upon their failure to credit the enemy with good judgment and equal military efficiency. Whether or not they have profited by recent experiences remains to be seen. Part I

General Tactical Doctrine Section I. GENERAL 1. GENERAL. The part on the General Tactical Doctrine of the Japanese Army is based on actual observation of their field maneuvers, and map problems, their operations against Russia and China, and a study of their field manuals. It is believed that their tactical principles, taught and studied for years, will not change materially. The tactical methods described here are primarily those which the Japanese consider appropriate for fighting in open country such as North Asia. They have had ample opportunity to test their tactics and to observe those employed by other Armies. Any study of theirteachings must be approached with the knowledge that the Japanese are quick to copy and may even improve on the tactics of their enemies. Technique or application of tactical principles, will vary, and is limited only by the imagination and initiative of individual commanders. Section II. OFFENSIVE 1. DOCTRINE. Japanese tactical doctrine insists vigorously on the inherent superiority of the offense, and Field Service Regulations state that the offensive should be resolutely taken. The object of all maneuver is to close quickly with the enemy

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so that the assumed Japanese superiority in close combat can be realized to the utmost. Even when the enemy strength is markedly superior, or when the Japanese commander has been placed temporarily on the defensive, he is supposed to use every effort to regain the offensive and take the initiative. The Japanese seem to feel that there is some mystic virtue in the attack and defensive combat is looked upon as a negative form of action to be adopted only when confronted with a markedly superior enemy. Even in defense, the offensive principle is strongly emphasized. Both as a result of this training and because of faith in the offensive doctrine, Japanese officers often reach attack decisions where, by all orthodox tactics, the situation patently requires some form of defensive action. Their teachings have been found to place very little emphasis on time and space factors, with the result that concentration of effort and the cooperation of all arms are frequently neglected. The division used for illustrative purposes in this section is the Japanese triangular division. It should be borne in mind, however, that while all Japanese divisions are not identically organized, tactics will not materially differ, although there will be differences in composition of columns and grouping of units. 2. FORMS OF ATTACK. a. Envelopment. (1) The Japanese consider the envelopment as the preferred offensive maneuver. Envelopment will be accompanied by a determined frontal pressure, while the main force attacks a flank. In ascending order of effectiveness, the envelopment may be single, double, or a complete encirclement (kanzen hoi). Contrary to generally accepted tactical principles, the Japanese are willing to try a double envelopment without any considerable numerical superiority and regard it as possible, sometimes, even by an inferior force which relies on surprise and deception. The Japanese commander may seek to obtain envelopment in one of several ways. (a) The force advances in two or more parallel columns, with one or more columns directed toward the enemy flank and rear during the advance to contact. (b) The force advances with certain units in the rear which can later be deployed to execute a flank envelopment. (c) After the force has encountered the enemy and partially deployed, some units may be moved laterally for envelopment if natural cover, darkness, fog, or smoke are available. (2) The procedure of (1) (a) above is considered the normal one for units of the size of a division; (1) (b) is especially applicable to small units, but (1) (c) is considered feasible only under most favorable conditions. Those units of a division executing the frontal holding attack often will make a close-in envelopment in performing their mission. Units of this force, such as squads and platoons, seek to obtain the effect of flanking fire (shageki hoi). (3) The question of which flank to envelop is decided by weighing normal factors such as terrain, location of hostile reserves and heavy weapons, etc. (4) To increase the effectiveness of the envelopment the Japanese often send a small force around to attack the enemy rear. When such a movement (ukai) is employed, the force sent around by a division in attack is relatively weak, comprising about a battalion reinforced by light artillery and a squad of engineers. The mission of such a turning force is often similar to that of a pursuit detachment; in fact this force may become a pursuit detachment if the main attack succeeds. b. Frontal attack. (1) Japanese regulations contain the usual admonitions against a frontal attack. Situations which may give rise to a frontal attack are those to which Allied armies are accustomed. In observed practice, however, the time element, or the fear of allowing the enemy leisure to improve his position, often is allowed to justify a questionable decision to make a frontal attack. (2) The main effort of a frontal attack is made against a "soft spot" in the line, leading in a decisive direction into the enemy rear areas. Effort will be made to penetrate deeply and swiftly at the first attempt by keeping narrow the battle fronts of units in the area of the main attack, making dispositions in depth, and coordinating employment of artillery. Tanks, if available, may participate. In general the Japanese are weak in artillery support and depend heavily on extensive employment of their infantry guns and infiltration practices. c. Comments. The impressions gained from a study of Japanese teachings on the forms of attack and their application in practice show that: (1) The Japanese will attack in many cases where the orthodox decision would call for less positive action. The attack may be rash and costly but will never lack vigor and determination. (2) The frontal attack, often with inadequate supporting arms, is not uncommon. 3. MEETING ENGAGEMENT (ENCOUNTER). a. Doctrine. The meeting engagement is the foundation of Japanese combat training, with official regulations giving more space to it than to any other form of combat. Japanese military writings define the meeting engagement as the collision of two hostile forces in motion, or the meeting of a force in motion with one which has halted but has not had time to organize a detailed position. Training strongly emphasizes this form of combat as allowing the optimum development of the alleged Japanese aptitude for swift and decisive offensive action. b. Artillery seems to be assigned missions in excess of its capabilities. Aircraft are expected to conduct constant reconnaissance of the situation of enemy and friendly troops as well as to cooperate with the artillery. Tanks may be used independently or in direct support of the infantry; when they are

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sent on distant raids, other mobile units, if available, may accompany them. c. The rules governing the Japanese in the meeting engagement may be summarized as follows: (1) The seizure and retention of the initiative. (2) Bold, independent action by subordinate commanders. (3) Prompt occupation of important terrain features. (4) Energetic leadership during combat. d. In the words of a Japanese writer, "The Imperial Army seeks to wage a short war to a quick and decisive conclusion. The meeting engagement conforms to this spirit and is to be sought whenever possible." 4. ADVANCE. a. General. The formations in the advance in day or night movements are similar to those used by other Armies and are governed by the same considerations. Parallel columns, each self-contained, are usual, unless precluded by the road net. When the enemy is strong in aviation and mechanized units, long columns are broken up into short serials containing antiaircraft and antitank weapons. Each main column is preceded by an advance guard, while the division cavalry, if present, usually acts as a reconnaissance screen in front of the advance guards. When the division is to advance at night, the division commander often sends forward in daylight a reconnaissance detachment and motorized infantry to seize important terrain features and to cover the night movement. As a meeting engagement becomes likely, the division commander modifies the formation, as needed, to facilitate the entry of the division into action with a view to enveloping one or both flanks of the enemy. b. Advance in two columns. (1) A study of Japanese tactical problems illustrates the division advancing in one, two, and three columns, with the two-column formation being the most favored. In the two-column formation the essential components of the division are disposed as follows: Reconnaissance Detachment 1st Cavalry

(Less detachment) Left column Right column

Advance guard 1st Infantry Regt. (less 3d Bn)

1st Co 1st Ind Antitank Bn

1st Bn 1st FA Regt

1st Co 1st Engr Regt

1/3 Decontamination Unit

1/3 Casualty Clearing Unit 2d Infantry Regt (less 3d Bn)

2d Co 1st Ind Antitank Bn

2d Bn 1st FA Regt

1st Engineers (less 1st Co)

1/3 Decontamination Unit

1/3 Casualty Clearing Unit Main Body Division Headquarters

Infantry Group Headquarters

1st Troop (Company) 1st Cavalry Regt

3d Bn 2d Infantry Regt

1st FA Regt (less 1st and 2d Bns)

1st Ind Antitank Bn (less 1st and 2d Cos)

1st Bn 1st Med FA Regt (150 mm Howitzer)

3d Infantry Regt

3d Bn 1st Infantry Regt

Advance Section, 1st Transport Regt

Division Trains

1st Transport Regt (less detachment)

1/3 Decontamination Unit

1/3 Casualty Clearing Unit With the above formation, the division commander expects, if anticipatory plans have been correct,

to execute an envelopment of the hostile left flank. Figure 80. (2) The composition of the march column illustrated above is covered in the division field order. It is noteworthy that an advance guard is designated by the division commander for the right column only; the left column merely receives an indication of the units composing it. This march formation is the result of the curious system of command which the Japanese employ. The division commander concurrently commands the division and the right column. In the latter capacity, he prescribes the detailed organization of the right column. The detailed organization of the left column falls to the senior commander of that column who designates an advance guard for its protection. Thus the advance guard of the left column is not an instrumentality for the protection of the division as a whole and is not directly under the control of the division commander. Therefore, as a meeting engagement becomes imminent, the immediate subordinates to whom the division commander issues orders directly are the colonel of the 1st Cavalry Regiment (commanding the reconnaissance detachment), advance guard commander (right column), commanders of the major components of the right column, and the commander of the left column. It is not clear how the division commander plans to coordinate the action of his right column advance guard with that of the left column. The term "advance guard" as subsequently used applies only to that which is controlled directly by the division commander. (3) In the above formation, the infantry strength in the advance guards of the 2 columns is about one-third of the division's infantry. When there is a greater number of columns employed, the combined infantry strength of the advance guards sometimes reaches half that of the division. Strong advance guards are characteristic of the Japanese Army in approaching a meeting engagement. c. Advance in other than two columns. An advance in one column is avoided because of the delay incident to developing the division for an attack. Therefore whenever that formation is adopted it is imposed by limitations of the road net. An advance in 3 columns was undertaken by a Japanese

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infantry division at Rangoon in March 1942, as follows: Left Center Right One Bn Inf (less one Co). One Inf Regt (less one Bn--less one Co). Inf Regt. One Co Engrs (less one Pl) with collapsible boats. One Co FA (Pack) with Ind Tpt Unit. One Bn FA (Pack) (less one Co). Tpt Unit (less detch). One Co Engrs (less one Pl). One Pl Engr. Div Med Unit (less detch). One Ind A/Tk Co (37-mm). Water Pur Unit (less detch). Detch Div Med Unit. Detch Water Purif Unit. One Co Army Sig Troops. One Co Ind Tpt Unit. Two Sections Div Sig Unit. One Section Div Sig Unit. Figure 81. The whereabouts of the remainder of the division is not known. The above illustration is taken from a British source which states that the initial advance of the division was made by 2 regiments, i.e., 6 battalions, spread over a frontage of 40 miles. The 3 columns were divided with approximately a 20-mile space between each. In this case the left column hardly could be considered as self contained. Use was made of roads, trails, and waterways wherever possible. In advance in 3 columns, the division commander remains the commander of the strongest column. More than 3 columns may be found, but such employment will be exceptional. d. Transport and trains. The division transport and trains normally follow the main columns of the division under division control in the following order: advance section transport regiment, unit trains, and the remainder of the transport regiment. Distances between these units are normally from 1 to 2.5 miles. The massed trains are under a commander, who is designated by the division commander. The advance section of the transport regiment consists of an infantry ammunition section, 2 artillery ammunition sections, and a veterinary section. Two field hospitals may be attached to the advance section of the transport regiment. e. Attachments. Units of light and medium artillery, antiaircraft artillery, observation aviation, antitank units and other supports frequently are attached to a division in the advance. f. Antiaircraft protection on march. For the advance, each front-line division may have attached an antiaircraft organization. This unit, often motorized, moves by leapfrogging from critical point to critical point along the axis of the division's advance. The guns go into position during the noonday halt, while passing defiles, while in bivouac, etc. If possible, antiaircraft units move forward by roads not used by the other elements of the division. The effective radius of action of one company of 75-mm antiaircraft artillery is considered to be 6,800 yards. g. Antitank protection on the march. In areas where there is a threat of enemy tank action against a column, the Japanese usually hold sometanks in readiness for employment against hostile tank forces. Active reconnaissance by both air and cavalry units warns the division commander of impending hostile tank action. Antiaircraft artillery may at times be employed to supplement normal antitank protection measures. h. Advance detachments. (1) There is a notable tendency for the division commander to send forward a mobile detachment in advance of the division for one of the following purposes: (a) To cover a night march to the probable battlefield where the division expects to be committed to action shortly after daylight. (b) To secure a vital terrain feature on the front of the division. (c) To execute demolitions of the road net and hamper the movement of the enemy. (d) To execute surprise attacks while the enemy is in march formation. (2) These detachments generally consist of the division cavalry, some infantry and engineers in trucks, and a company of light artillery. The infantry strength ordinarily will not exceed a regiment, except where the division plans an active defense. In this latter case, as much as half of the division may be pushed forward by forced marches to occupy a defensive position, while the remainder of the division follows more slowly with the intention of launching a counter-offensive against an enemy flank. 5. ACTIONS OF THE DIVISION COMMANDER IN APPROACHING A MEETING ENGAGEMENT. a. Reconnaissance. The formation of the advancing division contains in it the germ of the maneuver which the division commander expects to adopt if he encounters the enemy on the march. When the hostile force is reported approaching from a considerable distance, the division commander estimates where the battle will occur and communicates to his subordinates the general plan of maneuver which he expects to adopt, taking into consideration the use of terrain which the enemy considers generally impassable. He indicates time and place for the delivery of reports and designates a message dropping ground for the air service. His artillery and engineer commanders receive technical information from their own patrols marching with the advance guard and reconnaissance detachment. As contact becomes imminent the division commander, hitherto marching at the head of the main body of the principal column, moves forward on personal reconnaissance accompanied by appropriate staff officers. An advance message center may be designated behind the advance guard, one of the important functions of which is to facilitate collection and dissemination of enemy information. b. Orders. From his personal reconnaissance and the reports of his reconnaissance agencies, the division commander determines the area in which the division will make its decisive effort, the plan of maneuver, and the location of the division command

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post. He then issues fragmentary operational orders to initiate deployment of the division. Japanese Combat Regulations warn against waiting for over-detailed information before reaching a decision, and this injunction seems to authorize a very short reconnaissance phase at this point. 6. DEPLOYMENT OF DIVISION. a. Advance guard. (1) (a) The advance guard in the meeting engagement performs the following functions: it secures enemy and terrain information needed to form the basis of the decision of the division commander; it protects the deployment of the main body; and secures important terrain features to facilitate the subsequent attack. (b) The advance guard commander, bearing in mind these general functions, is expected to exercise initiative and boldness of action in specific cases. He obtains the necessary information by vigorous patrolling and, if necessary, by a small-scale attack. He protects the deployment of the division, either by offensive or defensive methods, and attacks when necessary to obtain important geographical points. Left to his own devices, however, the advance-guard commander usually elects to drive headlong into the advancing enemy, unless specifically restrained by division order. (2) As the advance guard closes to contact, its artillery prepares to furnish continuous support by leapfrogging from position to position in rear of the infantry. Normal artillery missions are to interdict (harass) the movement of enemy columns, to support the action of the advance guard infantry, and to perform limited counter-battery missions. Extreme ranges for interdiction by the 75's are 7,500 to 9,000 yards, but in practice missions are seldom fired at over 5,500 yards. Positions are chosen with a view to supporting the attack of the main body without change of position. The advance-guard artillery reverts to the control of the artillery commander at the time of the attack of the main body. (3) It must be borne in mind that the advance guard discussed is that of the column directly commanded by the division commander. The security detachments in advance of other columns are for their local protection only. b. Main body. (1) Deployment (a) In his basic decision for the deployment of his division, the division commander determines whether it will be coordinated or piecemeal. The basis for this decision is found in the Japanese Combat Regulations, a translation of which reads: "The division commander, in order to profit by or to extend an advantage won by the advance guard, may have to commit to combat each march column and each element of the main body successively upon arrival. However, if the situation permits, the division commander should seek the coordinated entry into action of his units, in which case he orders the deployment of each unit, establishes close cooperation between infantry and artillery, and coordinates the time of the infantry attack." (b) The question of whether to make a piecemeal attack thus appears to be decided largely by the success of the advance guard action. In map problems studied, the piecemeal engagement of all or part of a force often is justified by the necessity of seizing some prominent terrain feature or by the desire to get out of a defile. The object of the piecemeal attack is to take advantage of a sudden opportunity, while the coordinated attack aims at securing effective use of the combined arms at the expense of time. (2) Coordinated deployment. (a) As indicated above, the Japanese prefer a coordinated development "if the situation permits." The measures taken by the division commander to secure this coordination are: the assignment of a line of departure (tenkaisen) behind which the major units of his command are to deploy for the attack; detailed arrangements to assure coordination between the artillery and the infantry; and announcement of an hour of crossing the line of departure. The line of departure is usually an extension of the line held by the advance guard. If the enemy has secured the advantage of priority in deployment, the main body of the division may endeavor to escape a threatened envelopment or premature engagement with superior numbers by deployment along a line behind the advance guard or to the flank and rear thereof. In the event the deployment is to the flank and rear, the advance guard supported by all the division artillery covers the deployment and delays the advance of the enemy. (b) If the enemy, in anticipation of a collision with the Japanese troops, assumes the defensive, the deployment is modified to resemble the relatively cautious procedure of the attack of a position. In this case also the division commander tries to develop and attack in the same day to avoid giving the enemy time to improve his position. (c)The phase of the passage from march column to complete deployment is indicated by the following nomenclature used in Japanese regulations: (It must be realized that the following definitions are the translation of the Japanese and do not necessarily bear the same connotations in the Allied terminology.) Bunshin. Breaking from march columninto small ones out of hostile artillery range at the beginning of the approach march. Tenkai. Deployment along a line of departure (tenkaisen) with a view to performing an assigned combat mission. Sokai. Advance from the tenkaisen insmall (squad or section) columns. Sankai. Final deployment of front-line units to permit firing during the last few hundred yards of the assault.

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These phases are shown diagrammatically in figure 82:

Figure 82. (d) It is important to note that the coordinated attack from the Japanese point of view does not imply passing into assembly areas. However, this passage into assembly areas, called "kaishin" usually is observed in the attack of a position. If a coordinated attack follows the meeting engagement columns deploy directly behind the line of departure (tenkaisen) without halting prior to arriving on it. No special time is allotted for ammunition issue and final reconnaissance. (3) Piecemeal attack. (a) In the piecemeal attack the troops are committed to action in order of their arrival on the field. The division commander, decentralizing control to his column commanders, limits himself to a designation of routes of advance with a view to subsequent attack in the desired directions. No division "tenkaisen," no common hour of attack, and no detailed plans for coordination between the various arms are stipulated. (b) Despite the lip service rendered in regulations to the coordinated deployment and attack, the piecemeal method is very common on the map, n the maneuver ground, and in observed operations. Often this is the result of the precipitate action of the advance guard commander who gets himself seriously engaged on his own initiative. In such a case, a sort of hybrid deployment sometimes is executed, with a part of the main body going in piecemeal to help the advance guard, while the remainder makes an orderly deployment. Occasionally, a column commander has been known to stage a piecemeal attack all of his own in a situation where the prompt seizure of a terrain feature on his frontseemed essential to the subsequent success of the division. Such action was taken without waiting for orders or authorization from the division commander. (c)The rate of march of the infantry as it enters the zone of effective hostile artillery fire is reduced. In this zone the artillery moves forward by bounds of battalions while furnishing continuous support to the infantry. The theoretical rate of movement forward for this artillery is 2.5 miles per hour, although this may be increased to about 5 miles per hour if a battalion is allotted a road for its exclusive use. As the range limit is reached the battalion prepares to move forward. (d) Unit trains. When contact becomes imminent the transport regiment and the unit trains are halted in a sheltered location. The advance section of the transport regiment will often be as close as 2.5 miles to the anticipated contact, while the trains are normally about 5 to 6 miles in the rear of this line. The remainder of the transport regiment will be behind the trains. 7. DIVISION ATTACK ORDER. a. Deployment. The division deployment order gives a combat mission to the advance guard and march directions to the several columns with a view to executing a preconceived maneuver. While the elements of his command are carrying out these orders, the division commander watches the development of the advance-guard action and, with a minimum of delay, issues a verbal attack order to his principal subordinates. b. Attack order. The division attack order generally is issued in fragmentary form to the commanders concerned. c. Orders to infantry. In the organization of the infantry for combat, the advance-guard infantry becomes one wing and executes the holding attack. The second regiment executes the main attack, and it may deploy as the other wing along a line of departure (tenkaisen), generally in prolongation of the advance guard position. About one regiment of infantry is held in division reserve. This attack order is issued when the enemy is fixed in a given area where contact is expected, but often prior to making actual contact and before the advance guard has developed the situation. The order assigns to the infantry wing(s) specific objectives or a very general attack mission, depending upon the degree of clarity of the situation. Specific objectives would be such as "to attack the hostile forces on X ridge and seize the X position," while a general attack mission might be something like "to advance in the direction of Y and locate and attack the enemy's right flank." This latter type of objective is appropriate in an obscure situation when the plan of maneuver is predicated largely on a tudy of the terrain. In this case the attack direction given is one which is certain to take in flank any formation or position which the enemy may reasonably assume. A study of Japanese attack orders

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reveals that in an extreme case an order was issued 7.4 miles from the expected point of contact of the advance guards. d. Orders to artillery. (1) The artillery order indicates the location of the positions in general terms, and detailed reconnaissance is made by artillery commanders to determine the exact locations. Attachment of artillery to infantry is considered to be justified when: (a) The front of attack is very wide.

(b) Liaison with the infantry is difficult.

(c) Combat begins unexpectedly.

(d) The terrain is broken and wooded. (2) In the normal case the division retains control of the artillery and coordinates its action. Typical missions during the successive phases of the combat are as follows: (a) Phase I. During the approach march and deployment. Objectives (targets) in order of importance. Hostile artillery and machine guns firing at extreme ranges. Purpose. To cover the deployment of the infantry. (b) Phase II. During the attack. Objectives (targets) in order of importance. Hostile infantry, artillery, and reserves. Purpose. Close support of infantry. (c) Phase III. During final assault. Objectives (targets) in order of importance. The area of the decisive attack; the enemy reserves. Purpose. Neutralization and interdiction (harassing) of movement of reinforcements. e. Orders for piecemeal attack. The division attack order described in the foregoing applies to the coordinated attack. In the piecemeal engagement columns are organized into wings and receive attack directions and the attachment of the proper auxiliary arms. There is no coordinated deployment of any unit larger than a battalion. The artillery, less detachments, is kept under division control. The maneuver takes the form of a frontal collision without any effort to coordinate direction of the various columns to obtain the effect of envelopment. 8. FRONTAGES AND DISTANCES. a. Frontages. The following frontages are averages derived from studies of several problems: Battalion as a covering force 1,600 yards. Regiment in a holding attack 3,000 to 4,400 yards. Regiment in the decisive attack 1,600 to 2,200 yards. b. Distances. Distances from the line of departure. Division command post 2,200 to 3,300 yards. Artillery positions 600 to 1,500 yards. Division reserve 1,200 to 2,800 yards. Advance echelon, division transport 4,500 to 6,500 yards. Unit trains 8,800 to 11,000 yards. Remainder of division transport 11,000 to 13,000 yards. c. Assault. Attacking units do not try to retain alignment, and where the going is easy they press ahead. When gassed areas may be encountered the leading wave includes decontamination squads. A gassed area is avoided when possible; if it must be traversed, the local gas squads use their light decontaminating equipment to neutralize it. When such equipment is insufficient or absent, the troops are taught to cross the gassed area resolutely at an increased gait. The artillery advances by bounds close behind the infantry, while its forward observers advance with the infantry. As the attacking infantry approach the enemy positions, infantry and artillery fire is increased, and reserve units are brought up. The cavalry closes in on the enemy flank and rear, and victory is won by closing with the bayonet. The division reserve is used to extend and exploit an advantage gained, to meet a counterattack, or to extend the flank of the enveloping forces. If darkness interrupts the attack, it will be continued at night or renewed at dawn. 9. COMMENTS. a. Meeting engagement. In the Japanese meeting engagement all elements of the division show boldness and vigor. Speed in decision and execution is stressed in regulations and carried out in application. A commander encountering a Japanese division may expect to receive a quick and energetic attack, and, unless his covering forces are solidly deployed on their position, the Japanese attack is likely to upset his own plans for a coordinated attack. b. Piecemeal action. In practice the Japanese have shown an excessive willingness to engage in piecemeal action; Allied combat regulations, on the other hand, strongly favor the coordinated attack. Generally, according to Allied doctrine, the piecemeal attack is considered justifiable only if time is pressing, if there is a limited objective, and if combat superiority is on the attacker's side. If these criteria are applied to the situations in which the Japanese commander has decided to make a piecemeal attack, it will be found that time is pressing, and there is usually a limited objective, but not necessarily superiority. In fact, in the problems studied, the enemy was always superior, and in at least an equal state of readiness for combat. (In one map problem, the Japanese division was marching in one column while the enemy was in two). The only combat superiority was in the mind of the Japanese

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commander. Such a doctrine tends to make wasteful, piecemeal action the rule rather than the exception and develops a dangerous over-confidence, unjustified when faced by first-class troops. c. March formation. The march formation in which the division commander is also a column commander is awkward, for it needlessly burdens the division commander with the details of organizing and commanding a column. It complicates the handling of the advance guards which are usually not coordinated under division control. In fact, the advance guards of columns adjacent to the one commanded by the division commander generally are ignored in the division plan of maneuver. As a result the division does not appear to develop behind solidly organized covering forces which can assure an uninterrupted deployment through coordinated defensive action, even though the numerical infantry strength of the advance guards is usually large, averaging from a third to a half of the infantry of the division. d. Faults. The frequent use of the advance guard reinforced to make a holding attack and generally deployed on a wide front, renders control difficult and the organization of an effective attack even more difficult. The close-in envelopment so often chosen arises from a desire to get the attack off quickly and from the weakness of the organic artillery of the division. The Japanese teachings are to keep the artillery in a central location so that fire can be maneuvered over most of the front of both holding and enveloping attacks. If done this would restrict the scope of the possible attack directions. e. Reconnaissance. Map problems and terrain exercises which have been studied show that an insufficient time is allocated for reconnaissance and organization of the attack. In one map problem only 1 1/2 hours elapsed between the decision of the division commander and the jump-off of the so-called coordinated attack. While this is an extreme case, the impression of insufficiency of time for preparation is general. f. Summary. In summary, the characteristics of the Japanese division in the meeting engagement are: Rapid, aggressive offensive action by all elements. A tendency to uncoordinated piecemeal action. Development behind weakly linked covering forces. Frontal attack or restricted close-in envelopments. Inadequate artillery support. Sacrifice of proper reconnaissance and organization to obtain speed in attack. Attack through terrain generally considered to be impossible. 10. ATTACK OF POSITION. a. General. When the enemy has had time to occupy and organize a position, the Japanese commander endeavors to fight the decisive action outside of the organized area by turning the position. This is often attempted by an approach over terrain said to be impassible or under adverse weather conditions. The intention in both cases is to achieve surprise in the direction and time of attack. However, the presence of other Japanese units on the flanks often may limit the possible maneuver area. The technique of such an attack resembles that of the coordinated meeting engagement in the use of the approach march and the development of the situation by the advance elements; it differs in the amount of time necessary for reconnaissance and attack preparations. However, the need for carefully executed attack preparations, according to the Japanese, must not be made the excuse for allowing the enemy undue time to improve his position. As shown in map problems, when a commander encounters a position which has been strengthened during a period of several days, he ordinarily drives in the covering forces and reconnoiters during all or part of one day and launches his main attack the following morning. He appears quite capable of attempting all of this in one day if time is pressing. b. Development. (1) The hostile position normally will be covered by outposts which will vary in. strength from patrols to a relatively strong force supported by artillery and deployed as an outpost line of resistance. As the Japanese advance guards approach contact with the covering forces, and before the main body comes under long-range artillery fire, the division commander usually orders his column into assembly areas. (2) It should be noted that going into assembly areas is a phase of the attack of a position not ordinarily present in the meeting engagement. In problems studied these areas are from 2,200 to 4,400 yards from a hostile outpost line and thus 4,000 to 6,000 yards from the hostile artillery. In the typical case of the division advancing in two columns three assembly areas are designated, one for the main attack force, one for the force making the secondary effort, and one for the division reserve. The assembly is covered from positions about 1,100 to 1,600 yards in advance. 11. DRIVING IN COVERING FORCES. a. Procedure. In order to obtain adequate information about the main defensive position, the Japanese division ordinarily first drives in the hostile covering forces and then executes the necessary reconnaissance for the main attack. If these covering forces are weak and do not form a continuous front, the advance guard commander drives them in on his own initiative; otherwise, the division commander organizes the operation under cover of strong artillery support. In the typical case, this attack takes place in the afternoon of one day, and is followed by attack of the main position at daylight the next day

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or shortly thereafter. When the opposing forces occupy positions very close together, two nights may be necessary to get the attacking forces and materiel into position. b. Continuous attack. This procedure of successive attacks, while designated as orthodox in Japanese Combat Regulations, often is replaced in practice by a continuous attack on both outpost and main position. It is not clear when this variation is considered justified, but apparently the deciding factors are whether the artillery can support the attack through both positions without displacement (moving) and whether the time element is pressing. When the continuous attack is made, that on the outpost line becomes a phase of the main attack, and the attacking infantry usually pauses briefly on the captured position, and then continues the assault. In about half of the map problems studied the continuous method was adopted, although there was no apparent need for especial haste in launching the attack. 12. ATTACK ORDER. While the infantry is deploying in assembly area (kaishin haichi) and the advance guard is driving in the covering forces, the division commander, after completion of his plan of attack based on reconnaissance reports, issues his order for the final deployment of the division and the subsequent attack. The order includes familiar elements, except that the infantry in the assault is divided into right and left wings (occasionally into a right wing, left wing, and center) in accordance with the scheme of maneuver. 13.TECHNIQUE OF ATTACK. a. Infantry. (1) The typical disposition of the units in the assault is into wings, with the preponderance of strength in one wing assigned to make the main effort, while the other wing makes the secondary attack. The infantry units, in accordance with the plan of deployment, advance from the assembly areas to their assigned positions along the line of departure, where they make final attack preparations. When the attack is to jump-off about dawn (first light), the advance to the line of departure is made under cover of darkness; if made in daylight, all means are utilized to conceal and protect this movement. In problems, the lines of departure vary from 550 to 2,000 yards from the enemy main position, and the line is chosen so as to be protected from effective small-arms fire. When the attack on the main line of resistance and the outpost line of resistance is continuous, a pause and a realignment may take place along the rear edge of the outpost position which then becomes a phase line in the course of the attack. Attack objectives (terrain features) or attack directions are given the frontline infantry units according to the known details of the enemy position. Normally, the line to be reached by the attack is deep in the zone of the hostile artillery. The hour of attack is usually about 1 or 2 hours after dawn, as the Japanese have little confidence in the ability of their artillery to adjust and fire a preparation at night. In case of an attack entirely in daylight, a minimum of 4 hours is allowed between the time of the attack order and the assault to provide for distribution of the order and for artillery preparation. (2) In the decisive effort the average frontages of attack are: Yards Company 225 Battalion 400 to 600 Regiment 1,100 Frontages are 20 to 25 per cent greater for units making the secondary attack. (3) The division reserve is assembled under cover in the zone of the main effort approximately 1 1/2 to 2 miles from the line of departure. b. Tanks. When available, tanks are brought up with great secrecy to assault positions. Here they are attached to front-line battalions and jump off at the same time as the front-line infantry. The infantry is warned not to stop if the tanks are destroyed but to continue the advance. Tank missions are the breaching of enemy wire and destruction or neutralization of hostile elements. c. Artillery. (1) The division artillery frequently is reinforced with light and medium battalions. Its combat organization usually provides for a direct support group of from one to two battalions for each wing without any artillery being held in general support. If a fourth battalion is attached it may be employed as a counter-battery group in a relation similar to general support. Fire missions are varied according to the phases of the proposed action, a typical assignment where there is no reinforcing artillery being the following: (a) Phase I. Attack of the outpost position. Missions: counter battery by one battalion, direct support fire by two battalions, with special attention given to the troops of the main effort. (b) Phase II. From the occupation of the outpost line of resistance to the opening of the artillery preparation. Missions: counter battery, harassing, and interdiction fires. (c) Phase III.The artillery preparation. 1. Duration one to two hours. 2. Subdivisions (approximate). 1/2 hour of fire for adjustment (ranging) in daylight. 1/2 hour for wire-cutting accompanied by slight counter-battery. 1/2 hour of fire on infantry position. (d) Phase IV. The attack. Mission: direct support fires with particular attention to the main effort. (2) All the division artillery deploys for the attack of the outpost line of resistance. The artillery positions are pushed forward to within 500 to 800 yards of the infantry line of departure so as to be able to support the attack of the main position without moving. At the time of the attack on the main

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position, 1 or 2 artillery companies often are attached to the main effort as accompanying artillery. (3) The ammunition allowance for the light artillery in an attack of a position is usually 3 to 3 1/2 days of fire (1 day of fire 75-mm equals 300 rounds). (4) Two to three airplanes normally are attached to the artillery for observation and command purposes. (5) Implied gunnery methods seem to be elementary, with main reliance on axial ground observation and with observation posts generally close to the guns. The Japanese Combat Regulations imply, however, that the artillery is capable of registering at night and of opening fire promptly at dawn. d. Antiaircraft artillery. The usual attachment of antiaircraft artillery to a division appears to be a battalion, consisting of three gun companies (and sometimes a searchlight company). Such machine guns as are in this battalion are for its own local defense. In the attack of a position, the gun companies are placed in the zone of the main effort, in initial positions about 2,700 to 3,300 yards from the line of departure of the infantry. e. Cavalry or reconnaissance. About one platoon is normally attached to each wing for duty as messengers and orderlies. The remainder is divided for flank protection with the bulk on the decisive flank. As the strength of the division cavalry regiment is light, the combat value is not as great as might be expected. f. Engineers. Engineer missions in the typical case are: maintenance of communications; assistance to the artillery and tanks; wire cutting; and the removal of obstacles. g. Command posts. The average distances of command posts from the line of departure for the attack of the main positions are: Yards Infantry regiment 1,100 Artillery regiment 2,700 Division 2,700 h. Destruction of obstacles. The Japanese normally assume there is some wire in front of the hostile position. An attack order therefore includes provisions for cutting the wire in one of the following ways: (1) By detailed destruction fires by the artillery. (2) By artillery fire in the most important places, supplemented elsewhere by hand cutting by infantry, tanks, and engineers. (3) By the artillery cutting the wire imperfectly at all points, with the cutting to be completed in detail by infantry, tanks, and engineers. Where there are several bands of wire, it is normal to make the destruction of the first band the exclusive duty of the infantry and engineers. i. Medical troops. About one-third of the medical troops are assigned to support each wing; the remainder are in reserve. These detachments set up and operate division collecting (dressing) stations located behind the regimental dressing stations. Locations are from 1,600 to 2,200 yards behind the line of departure. Two field hospitals are set up about 2,500 to 4,000 yards from the line of departure; the division is capable of setting up one additional hospital held initially in reserve. j. Ammunition supply. The advance section of the transport regiment (senshin shicho) ordinarily opens an infantry ammunition distributing point in rear of each wing as well as one artillery distributing point. 14. ASSAULT. There is little in tactical problems which bears specifically on the conduct of the assault. While the infantry pushes ahead boldly without regard to alignment, and with bayonets fixed, the division commander influences the action by the fire of his artillery and by the division reserve. This reserve may be used to meet a counterattack, to exploit a success, or to cover the flank of a penetrating unit. The division reaches its objective prepared to pass to the pursuit in accordance with plans previously made by the division commander. 15. COMMENTS. a. Characteristics. In their concept of the attack of a position the Japanese show complete disregard of casualties in pressing it to a successful conclusion. Their campaigns initially met with a great measure of success in tropical countries because they had trained extensively in jungle terrain and adapted their technique to capitalize on what their enemies considered hindrances and handicaps. The following characteristics were common to their campaigns: (1) Careful, meticulous staff work in the detailed planning of the operation, training and equipping of the forces to be used, and in coordinating and carrying out the action. (2) Great boldnesses, both in the conception of the operation and in execution of its details. (3) Fearlessness of the enemy and the ground weapons he had at his disposal. (4) Disregard of casualties in attaining an objective. (5) Use of surprise and deception. (6) Refrainment from advancing to the attack before interdiction of all nearby enemy airfields and attainment of air superiority in the area of the attack. (7) Great speed in infiltration, envelopment, and pursuit. (8) Willingness to attack through terrain normally considered impassable and in adverse weather conditions. b. Criticisms. (1) The willingness with which the Japanese commander will order an attack on an outpost simultaneously with the attack on the main position has already been mentioned; this is done

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in spite of the prescription in Combat Regulations which indicates that effective reconnaissance can only be obtained after the outposts have been driven in. His shortening of the time allowed for reconnaissance and preparation has in many cases reduced the already slender chances of reaching the final objective. (2) The deployment of the division is generally along orthodox lines, excepting that the assembly areas are invariably within effective enemy light artillery range. (3) The plan of maneuver offers nothing of special advantage for the direction of the attack, as it usually culminates in a parallel, frontal, or semi-frontal push executed by the two wings of the division, with one wing--the decisive one--somewhat stronger in infantry and artillery. However, if this form of maneuver is accepted, there is still a weakness in the absence of a decisive massing of force on a decisive point. (4) Japanese use of artillery is subject to much criticism. The fundamental fault is that there is generally not enough of it. This weakness in artillery may be the result of a lack of appreciation of the need for adequate fire support, or of a feeling that past experience has not demonstrated the need for stronger artillery. The period of daylight fire for adjustment prior to the fire for effect reduces tactical surprise and diminishes the moral effect of the preparation. This unwillingness to fire the preparation unobserved at night would suggest low gunnery efficiency. Also the absence of general support artillery reduces the flexibility of the artillery fires and limits the ability of the division commander to intervene promptly in the action by the use of his artillery. From the picture drawn in the tactical problems, one can feel reasonably sure that the Japanese infantry will jump off, even though their extensive preparations have neither destroyed hostile wire nor neutralized the enemy artillery and machine guns. The detailed workings of the direct support fires are not described in the problems studied; hence, no estimate of their effectiveness can be made other than that implied by the absence of detailed plans for infantry-artillery liaison. (5) While the detailed administrative plan of the attack does not appear in the problems studied, such establishments as are located on the situation maps are considerably closer to the front line than is considered standard. Lack of depth is characteristic of both the tactical and administrative dispositions of the Japanese division and has its origin in their lack of appreciation of the effect of modern fire power, particularly that of the hostile artillery. A period of contact with a well-equipped enemy may furnish correctives for this tendency. (6) In general, although the adverse criticisms are numerous, it is not to be assumed that the Japanese will persist long in these errors, if errors they prove to be on the battlefield. The Japanese gifts for adaptation and improvisation can be counted upon to remedy quickly many of the faults in their doctrine. 17b. PURSUIT. a. General. Japanese regulations and tactical doctrines place the normal emphasis on the need for pursuit to reap the full fruits of victory. They also recognize the existence of many deterring elements, such as fatigue of the troops, disorganization, and depletion of supplies. In spite of these, the Japanese commander is urged to pursue relentlessly to avoid the need for another battle against a reorganized and possibly reinforced enemy. b. Preparation for pursuit. The Japanese commander throughout an engagement plans constantly for the pursuit. The enemy is observed carefully, especially at night, for signs of an intention to withdraw. To determine this intention, the Japanese use ground reconnaissance patrols and spies, and they may use observation aviation if it is available. When these means are inadequate, the commander is urged unhesitatingly to stage a local attack to gain the required information. While he is pushing this reconnaissance, he makes preparation for a possible pursuit. These preparations take the form of alerting certain units for immediate pursuit, of assembling sufficient ammunition for the operation, and of outlining a tentative administrative plan. c. Types of pursuit. While the quick destruction of the defeated enemy is the object of all pursuit, this cannot always be effected immediately by a single simple maneuver. In seeking to destroy his opponent, the pursuer usually will try to fix him by direct pressure while enveloping or turning one or both flanks. If this maneuver fails, he may try to push the retiring enemy off his line of retreat or into a disadvantageous position where he can be attacked more effectively. In recognition of these differing situations, Japanese writers treat the operation under two types: Type 1, where the enemy is destroyed near the field of battle where he sustained his initial defeat; and Type 2, where the enemy has partially succeeded in extricating himself, and the pursuer must take distant objectives deep in the enemy's rear after resuming semi-march dispositions. In both types, the destruction of the enemy is accomplished by fixing him with direct pressure, while mobile pursuit detachments, moving around the flanks, occupy the critical points along his line of retreat and fall upon his rear. d. Technique of pursuit. (1) (a) Type (1). This form of pursuit finds its type example in the case of the daylight withdrawal of a hard-pressed enemy. The withdrawal is observed by the attacker, who immediately redoubles the frontal pressure, while available reserves are quickly formed into pursuit detachments which turn the enemy's flank and fall upon his rear. Boundaries between front-line units are readjusted as needed. The destruction of

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the enemy thus is accomplished in or near the original field of battle. The detailed action of the separate arms is essentially the same as in type (2), except that distant marches, with a reforming of march columns by the frontal pressure force of the infantry, are not required. (b) Type (2). This form of pursuit is regarded as the usual one by the Japanese. Most problems studied were of this type, wherein the enemy succeeds wholly or partially in disengaging himself and beginning a withdrawal. The initial withdrawal usually is accomplished under cover of darkness and may not be discovered at once. When the Japanese front line unit commanders find out what is occurring, they renew the attack individually and upon their own initiative in an effort to push through or around the hostile covering forces. As these Japanese units push through the enemy position, reserve units, formed into pursuit detachments, are started around the flanks with objectives deep in the enemy rear. When the Japanese front line infantry units have passed through the zone of resistance of the covering forces, the division commander halts them, organizes and sends forward additional pursuit detachments, and causes the remainder to form march columns to follow in the trace of the pursuit detachments. As this form of pursuit is considered to be usual, the subsequent remarks on the missions of the various arms apply specifically to this type, although they are also applicable with slight modification to Type (1). (2) Front-line infantry. All units are individually responsible for discovering the hostile intention to withdraw. After such discovery, they drive into the enemy covering forces on their own initiative. In order to get through the enemy covering forces the Japanese prefer to turn the organized localities by maneuver or by infiltration through the gaps. When neither is possible, a quickly organized attack on a narrow front is indicated. As the action of front-line units is decentralized, most of the division artillery is attached to front-line infantry regiments. Tanks are sent in to block the enemy's retreat and to attack his artillery and command posts. To avoid a serious loss of control, the division commander usually indicates a line in rear of the probable enemy covering positions where the troops halt and reform for further pursuit. A part of the frontline infantry is then organized with previously formed pursuit detachments. The bulk of the division reforms into march columns and follows after the pursuit detachments. (3) Artillery. When the enemy is discovered to be withdrawing, the artillery endeavors to disrupt the enemy's retreat by interdicting (harassing) the important defiles and bottlenecks in the road net. As the front-line infantry penetrates into the covering position, the artillery, attached to infantry units, follows by bounds close behind the advancing troops and concentrates its fire on the resisting enemy infantry. Some artillery is attached to pursuit detachments.

Figure 83. Pursuit formation. e. Comments. The Japanese pursuit in theory offers little variation from standard practice. Japanese regulations urge the utilization of all available transport, but, in the absence of especially attached motor transport, the division has been incapable of giving the required mobility to the pursuit detachments. The well-known marching power of the Japanese infantry can be counted upon to compensate in a measure for this deficiency in motor transport. The pursuit is a form of operation thoroughly in line with the offensive spirit of the Japanese Army, and the war in China has shown that the Japanese pursue just as vigorously and unhesitatingly as their regulations prescribe. The North China campaign was particularly rich in examples of rapid pursuit. In the advance down the Pinghan and Tsinpu Railways, the Japanese put their pursuit detachments on freight cars and sent them far into Chinese territory, while the main body of the divisions followed partly by rail and partly by marching. Where rail transportation was not available, the Japanese organized special motorized units (kaisoku butai) to give rapidity to their pursuit. 17. RIVER CROSSING. a. General. (1) Japanese river crossing methods are essentially those of other Armies. Success is sought through surprising the defense by concealment of preparations and rapidity of action after the crossing starts. Normal attachments to a division contemplating a river crossing include units of antiaircraft, observation aviation, engineers, artillery, and armored cars.

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(2) The advance to the river is made on a broad front and is preceded by advance detachments to drive back enemy patrols from the near bank and to seize existing bridges, bridging materials, and boats. The aviation reconnoiters both banks of the river, while the Engineers conduct a detailed reconnaissance for possible ferry and bridge sites, and for local engineer supplies.

Figure 84. Typical river crossing. b. Comments. The river crossing methods described are in general so orthodox as to occasion little comment. However, the pooling of all the Engineers into a unit in general support of the crossing is a deviation from the usual method of attaching Engineers to the crossing commanders. The weakness of the division artillery makes extremely difficult the support of an operation on a wide front such as a river crossing. It becomes difficult to allot any artillery to the distant feint, without which there cannot be much deception. The use of the reserve to create false activity, and the strict measures taken to control spies among the civilian population, are further examples of the emphasis placed on secrecy and deception in all Japanese operations. 18. NIGHT ATTACK. a. General. The Japanese Army has a strong partiality for the night attack. This form of combat favors the bayonet fighting stressed in infantry training and tends to cover the weaknesses in artillery and cooperation of the combined arms which have characterized the Japanese Army. The Japanese are further encouraged in their faith in night attacks by successful experiences in the Russo-Japanese War and subsequent operations in China and during the early part of the present war. The night attack sometimes is referred to as "a specialty of the Japanese Army" and as "a traditional Japanese method." b. Advantages and disadvantages. The advantages attributed to the night attack are avoidance of losses, concealment of movement, and rapidity in closing with the enemy. Disadvantages conceded are loss of cooperation between units, loss of unified direction, a greater chance of mistakes, and confusion. The Japanese believe trained troops can overcome these disadvantages and succeed even when opposed by superior numbers. Thus, in justifying a night attack, there is a tendency to reason, "The enemy is too strongly organized or too numerous for us to hope to defeat him in daylight; only by a night attack have we any possible chance to defeat him and accomplish our mission." c. Occasions for night attacks. (1) Night attacks are considered appropriate for units varying in size from company to division. Orthodox situations calling for night attacks are the following: (a) A large unit (division) wishing to extend or complete a success during a daylight engagement may continue the attack at night. (b) Large units (divisions) may use a part of their force to seize by surprise points needed to assist the attack of the following day. (c)Local night attacks may be used to distract or mislead the enemy and to conceal Japanese activity elsewhere (for example, a night withdrawal). (2) These three occasions mentioned above are referred to as orthodox since they are the ones described in Japanese Combat Regulations. In practice the night attack has been used in the following additional situations: (a) By a large unit to prevent a hostile night withdrawal or to complete the defeat of the enemy before he could be reinforced. (b) When superior fire power of the enemy prevented the reaching of attack objective in daylight. d. Hour of attack. Combat Regulations indicate that the period just after dark and just before daylight are desirable hours of attack. In 4 peacetime exercises the hours were, dusk, 2400, 0030, and 0200. The considerations involved in choosing these hours were that the engineers need at least 2 hours to cut paths in the hostile wire prior to the attack and that the objectives should be reached shortly before dawn to allow a coordinated renewal of the attack from the new line of departure a little after daylight. e. Reconnaissance. Regulations insist on the importance of a thorough knowledge of the terrain on the part of all commanders involved in night

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attacks. Japanese commentators stress the need of detailed information as to the location of enemy strong points, machine guns, obstacles, searchlights, etc. In observed peacetime practice, however, the time allotted for reconnaissance was usually quite short. Concrete examples noted were: (1) A regimental commander, hard pressed in a meeting engagement, decided at 1530 on a night attack at dusk, less than 4 hours later. (2) In two separate map situations, two brigade commanders decided at 1600 and 1700, respectively, while in the course of attacking a prepared position, to make a night attack shortly after dusk of the same day. These decisions are believed to have been made at such time and under such conditions as would preclude much real reconnaissance. f. Objectives. (1) "The objectives of a night attack are limited and are shallow in comparison to those of daylight attacks." (Japanese Combat Regulations.) Each subordinate unit receives terrain objectives as clearly defined as possible. Villages are avoided, since they are difficult to attack at night. (2) Objectives assigned are often ambitious. The boundaries of tactical localities assigned frequently are not clearly defined features which guarantee against errors in the dark. The final objective is usually the rear edge of a position about 1,100 yards deep. Apparently about half of this is believed enough for the first bound. It will be seen in the discussion of attack dispositions that this depth of objective requires a night passage of lines on the first objective. Advance infiltration units usually precede the main attack to neutralize the enemy. g. Conduct of attack. (1) Infantry. (a) The infantry of a night attack usually is disposed in two assault echelons and a reserve. If the objective is shallow, one assault echelon may suffice. In the normal situation, however, a first wave rushes forward and seizes the line which constitutes the first objective; the second wave passes through the first and moves on to the second objective. This second wave also has the missions of repulsing counterattacks and destroying enemy searchlights. The relative strengths of the first and second waves depend on the relative strengths of the first and second positions. In general, a force of from one or two platoons, commanded by an officer, is given the mission of attacking and occupying a definite enemy strong-point. A battalion generally attacks in a 450 to 550 yard sector, with 2 rifle companies in the first wave, 2 companies less a platoon in the second wave, and a platoon in battalion reserve. The battalion is expected to reach and occupy 2 objectives, the more distant being some 1,100 yards from the jump-off line. Where the rear objective is more distant than this, or the going is more difficult, 2 battalions may attack in column, the rear battalion being responsible for the taking of the second objective. The following is a schematic representation of a typical attack formation.

Figure 85. Battalion in night attack. (b) In the foregoing dispositions, companies 1 and 2 are in a line of platoons, each platoon being in a line of squad columns; companies 3 and 4 are about 100 yards behind the leading companies in a line of platoons, each platoon in a column of squads. Exact intervals between platoons are not known, but the frontage of a company is relatively narrow, about 100 to 175 yards. The battalion reserve follows the preceding company at about 50 yards. While the Japanese recognize that this dense formation is highly vulnerable to fire, they consider it justified by ease of control and effectiveness of shock action. (c)The infantry assault is with the bayonet without firing. Battalion guns may be used against searchlights and obstacles, and machine guns will participate in protective fires. (2) Wire-cutting, gas, and smoke. Engineers are attached to the assault battalions for cutting lanes through the enemy wire. This cutting starts secretly after dark, about 1 1/2 to 3 hours before the attack. About 3 lanes per battalion apparently are considered sufficient. If gassed areas are to be encountered decontaminating detachments precede the assault; chemical detachments for laying smoke screens also may be pushed forward if the enemy searchlights are troublesome. (3) Artillery. (a) Night attacks are classified as "kishu" and "kyoshu." The first is translated as "attack by surprise" and the second "attack by force." Attack by surprise (kishu) is characterized by an infantry rush with bayonet, but without a preparation or accompanying fires by the artillery or infantry weapons. Attack by force (kyoshu) implies coordinated accompanying fires and possibly a preparation. The attack of the first objective is an attack by surprise (kishu), unless the enemy is thought to be expecting a night attack; the attack of the second objective is an attack by force (kyoshu). (b) A battalion of artillery normally supports an infantry regiment. The artillery commander, after conference with the commanding officer of the infantry, prepares fires to be available on call during

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the attack. The usual method of call is by rocket. In preparing fires, special consideration is given to possible enemy counterattacks. The artillery may be required to cut wire, but this is costly in ammunition. (4) Maintenance of direction. Maintenance of direction at night, being difficult, requires special measures. Devices used are-- (a) Compass bearing. (b) Road markers, such as white stakes, strips of paper, lines of chalk or flour, and ropes. (c)Flares. (d) Searchlights. (e) Shells fired for direction of artillery. (f) Rear lights giving direction by alignment. (g) Company commanders wearing two crossed strips of white cloth on their backs; lieutenants, a single strip. (5) Comments. (1) An enemy facing the Japanese Army may expect to receive frequent attacks at night, at least until this form of combat proves definitely unprofitable. Factors favoring the success of such attacks are: (a) Detailed training in night marches, maneuvers, and attack. (b) Special emphasis placed on use of the bayonet and hand-to-hand fighting. (c) Emphasis placed on the element of surprise in the execution of night attacks. (d) Constant use of infiltration, outflanking movements, and attacks from the rear in country where cover is dense. (2) It is believed that the following defects will militate against the success of the Japanese night attacks in the face of an alert enemy: (a) An over-readiness to attack at night in the hope of retrieving a check received in daylight fighting. (b) Insufficiency of time allowed for reconnaissance, planning, and distribution of orders. (c) Over-ambitious objectives. (d) Mass attack formations highly vulnerable to enemy fire. (e) Reserve units following on the heels of assault waves where they would soon be lost to control of the commander. (f) Inadequacy of artillery support to neutralize enemy automatic weapons and to cover the operation with protective fires. (g) An attempt to execute a night passage of lines in the course of an attack. (3) Against an enemy who has not been determined to hold at all cost, the night attack has had and may be expected to have many successful applications. However, against a vigilant enemy, strong in automatic weapons, it has proved costly to the Japanese. Section III. DEFENSIVE 1. GENERAL. a. Japanese attitude. The defensive form of combat generally has been distasteful to the Japanese, and they have been very reluctant to admit that the Imperial Army would ever be forced to engage in this form of combat. So pronounced has been their dislike for the defensive that tactical problems illustrating this type of combat are extremely rare. b. Object. The object of the defensive is to inflict on the superior hostile forces such losses by fire power, disposed appropriately on the terrain and behind man-made defensive works, that the initial disparity of forces becomes equalized to the point of authorizing a passage eventually to the offensive. c. Doctrine. The old Combat Regulations (Sento Koyo), superseded in November, 1938, based discussion of the defensive on the active defense. The newer regulation (Sakusen Yomurei) takes the passive defense, assumed in the presence of overwhelmingly superior forces, as the typical case, of which the active defense is a variant calling for special discussion. This latter viewpoint is definitely contrary to former practice where a return to the offensive is always present in the plans for the defense, even though the initial dispositions are not those of an active defense in the true tactical sense of the word. This indicates a change in official emphasis, but probably means no real change in the practice of the defense, since in actual combat and in illustrative problems there is always present the characteristics of active defense. 2. DEFENSE OF A POSITION. a. Selection of the position. The qualities sought for the main battle position (observation, protected flanks, fields of fire, covered lines of communications, obstacles, etc.) are those standard in all schools of military doctrine. In accordance with the current trend, the Japanese emphasize the importance of antitank obstacles across the front and flanks of their position. In the presence of an enemy who may use gas, the main line of resistance will avoid depressions where it is likely to accumulate. The importance of cover and concealment is fully recognized. Reconnaissance for the position is made by the division commander, assisted by his artillery and engineer commanders as well as other appropriate staff officers. b. Occupation of the position. When the general outline of the position has been determined, the division commander directs the subordinate elements of his command to their respective defense areas where they deploy directly upon the position which they are to occupy. The division commander directs his cavalry (often reinforced by some infantry) to cover the deployment and organization of the position. This force takes position far enough in advance of the area to be organized to keep hostile artillery fire off the main line of (a) Determination of the probable direction of hostile attack.

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(b) The probable direction of a division counterattack or counteroffensive. (c) Antitank measures. (d) The assignment of troops within the defensive area. (e) The use of artillery including antiaircraft. (f) The composition and location of the division reserve. (g) The use of tanks. (h) Communications and liaison. (i) Supply. The completeness of the reconnaissance is dependent on the time available. He then issues his defense order. c. Organization of the position. (1) The defense is based on a main position (shujinchitai) which is held to the last extremity. The division commander normally divides the defensive position into right and left sectors (chiku) the defense of which he assigns to his two senior infantry commanders. In cases where the front is unusually broad, or a counter-offensive is planned, he may add a center sector. The Infantry is disposed along the main line of resistance by units of battalions, with frontages determined by the terrain and mission. When a broad defense is adopted, battalion centers of resistance are organized for an all-round, independent defense, in which the lateral intervals can only be partially covered by fire. In this form of defense, reserve units, kept as large as possible, are held mobile to attack hostile elements which filter through. Battalion frontages in the broad defense along the main line of resistance may approach 3,000 yards, while the normal defense frontages average from 800 to 2,000 yards. (2) Support and local reserve units are deployed behind the front line infantry to give the position a depth of 700 to 1,500 yards. Throughout this zone automatic and antitank weapons are echeloned in depth. Usually heavy machine guns are found deployed along the support position, from which they attempt to cover the front with interlocking fires (criss-cross fires). 3. THE OUTPOST POSITION a. The outpost position (Keikai Jinchi) is indicated by the division defense order and is garrisoned by troops dispatched by the sector commanders. The order may specify the strength of the garrison, its mission, and manner of withdrawal. Troops on the outpost line of resistance normally pass to division reserve when relieved The outpost line of resistance is generally from 1,500 to 3,000 yards in front of the main line of resistance, so as to be within supporting range of light artillery. Combat Regulations tend to recommend the shorter distance so as to obtain the fire support of machine guns from the main line of resistance. However, in observed practice, the Japanese seem to attach little importance to the uncertain support of long-range machine gun fire. b. The normal missions of the outpost line of resistance are to obtain enemy information by observation and patrolling, to cover the main line of resistance and prevent its surprise to delay the hostile attack on the main line of resistance, and to act as an advance defensive position (Zenshin Jinchi). Missions (1) and (2) are the minimum case, where the outpost line of resistance is not much more than a line for observation and reconnaissance with little defense strength. Missions (3) and (4), frequently present in observed practice, imply a considerable increase in defensive means approaching that of a true advanced defensive position. c. The troops assigned to garrison the outpost line of resistance, while variable in strength with the mission assigned, are kept to a minimum. For the front of a division, 1 to 2 battalions of infantry were normal in the problems consulted. Comments on these problems indicate that about 2,000 yards for the infantry company is considered the absolute maximum extension consonant with the retention of any sort of control by the unit commander. With the usual weak allotment of troops, it is impossible to hold the line continuously. Instead, important points are occupied in some strength, while the intervals are covered by observation and fire as far as possible. The Japanese do not expect to be able to organize a continuous system of infantry and artillery fires in front of the outpost line of resistance. With the help of attached engineers, the infantry strengthens the outpost position by defensive works to the extent permitted in the time available. In the case of the defense on a very wide front the outpost line of resistance is reduced to a line of observers, or may even be dispensed with entirely. 4. ADVANCED DEFENSIVE POSITIONS. a. The division commander at times may order the occupation and organization of an advanced defensive position (Zenshin Jinchi) in the zone between the outpost line of resistance and the main battle position. The purpose of such a position is to prevent as long as possible the occupation of critical points of terrain by hostile forces near the main defensive zone, to delay the enemy preparations for the attack, and to induce the enemy to launch his attack in a false direction which will expose his flan. The organization of a formal advance defensive position is not standard Japanese practice, although the assignment of such a mission to the outpost position is not uncommon. Typical cases where the advanced positions have been organized are: (1) where in order to obtain observation the outpost line of resistance has been pushed well forward, leaving an important ridge in the foreground of the main battle position ungarrisoned; and (2) where an oblique position is organized between the outpost position and the main battle position, with one flank resting on the outpost line of resistance while the other rests on the main line of resistance, thus inducing the enemy to expose a flank. b. The garrison of the advance position may come from the troops assigned in the outpost position

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or from those of the main battle position. reinforced by machine guns and antitank weapons. Artillery elements may be assigned support missions. The delicacy of withdrawing this force is fully appreciated by the Japanese, and the division commander is cautioned to issue clear and simple missions to this force and to specify the time and manner of withdrawal. c. In cases where the division commander elects not to organize an advance position, the zone between the outpost and the main battle position is covered by observers sent forward by the front line infantry battalions. These troops patrol the foreground, cooperate with those of the outpost line of resistance, and execute local reconnaissance. 5. RESERVES. a. Reserves are held out by all units from the company upward for the purpose of executing counterattacks. The division reserve generally varies in size from 1 to 3 battalions. Its position is initially from 5,500 to 6,500 yards in rear of the main line of resistance, in a sheltered position conveniently situated with respect to the probable counterattack of the division. Tanks often will be attached to this force. Motor transportation generally is not attached to the reserve because of the paucity of organic motor transport in the division. b. When the division commander has planned an active defense, the general reserve as a rule will not exceed a third of the infantry strength, since front line units themselves are expected to return to the offensive at the earliest opportunity. 6. ARTILLERY. The artillery is disposed in depth behind the main line of resistance so as to be able to mass its fire in support of the main position in the area of the hostile probable main effort. One or two artillery companies may be initially in forward positions to support the outpost positions or an advanced defensive position. Artillery positions generally are echeloned through a zone about 2,500 yards in depth, extending to the rear from a line about 1,700 to 2,200 yards behind the main line of resistance. Ground observation is not considered effective under normal conditions for ranges over 5,500 yards. 7. COMMAND POSTS. a. General. Command posts generally are established in well sheltered positions in rear of the main line of resistance; that of the division is usually located at a distance of about 5,500 yards, that of the infantry group at about 2,700 yards, and that of the infantry regiment at about 1,300 yards in rear of the main line of resistance. b. Organization of the ground. (1) In the early phases of the reconnaissance of the position, the division commander gives initial instructions to his engineer regarding the supplying of entrenching tools, material, and equipment. The defense order indicates the priority of work, a typical one being the following: (a) Principal points on the main line of resistance. (b) Fields of fire and observation posts of the main line of resistance. (c) Obstacles in front of the main line of resistance. (d) Communications, trenches, and personnel shelters. (2) In tactical problems it is seldom assumed that there is time available for elaborate field works. The division usually has from about 3 hours to a half day to complete its organization of the ground. Three hours is considered the minimum required to organize a rudimentary system of trenches and obstacles along the main line of resistance. The time-work unit in engineering calculations is the 12-man squad which is considered capable of digging about 25 yards of standing fire trench in a little over 3 hours. In situations in which the use of gas by the enemy is expected, the division commander will order the distribution of protective materials at suitable points throughout the area. Stress is laid on camouflage and the construction of dummy field works, the completeness of which is dependent upon the time available. A typical plan followed by the Japanese in the construction of the field works of a company position on the main line of resistance is illustrated in figures 86, 87, and 88. Conduct of the defense. (a) Advanced elements. As the enemy approaches the position, he will encounter first the advanced elements of the defense (the outpost line of resistance or advanced defensive position). These forward elements conduct themselves in accordance with their mission which normally directs their withdrawal into division reserve before becoming seriously engaged. Artillery companies in forward positions delay the hostile advance, cover the withdrawal of the infantry, and then fall back to prepared positions in the artillery zone where they revert to the control of their organic commander. The cavalry which has withdrawn to the flank, while maintaining contact with the advance positions, will carry out its normal missions. (b) Defense of the main line of resistance. As the hostile infantry forms up for the attack on the main line of resistance, the defensive artillery brings down its counter preparations fires. Tanks may be sent forward, covered by artillery, to upset the preparations of the enemy. As the hostile attack enters the zone of infantry fires, the sector commanders conduct the defense of their sectors, first by fire, then by the bayonet in front of their entrenchments. Commanders of all units counterattack unhesitatingly as the integrity of their positions becomes threatened by the hostile attack. The artillery assists the close-in defense by standing barrages and concentrations brought down within the defensive position. (c) The counterattack or counteroffensive. The division commander is constantly on the alert to determine the proper time for the division counterattack

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or counteroffensive. The favorable moment will generally be at the time the hostile attack has been stalled; when the enemy has blundered into an unfavorable position; when a favorable opportunity has been created by a successful local counterattack; and when the enemy pauses to reorganize or consolidate his position. The plan for a return to the offensive will be made tentatively well in advance of the occurrence of the opportunity. The direction of the counterattack generally will be aimed at an envelopment; however, at time, the situation may compel a purely frontal attack. The mass of artillery, and tanks if present, will support the counterattack or counteroffensive. The division commander may directly control the counteroffensive, or he may delegate control to a sector commander. 8. COMMENTS. a. Aggressive character. Since the defensive in Japanese regulations and military writing is branded as a negative form of combat, un-Japanese in essence and spirit, it has been very difficult to write a tactical problem for which officers were willing to advocate a defensive solution. In problems studied, the basic decision to defend already had been made by the division commander, a school device to control the offensive elan of the student officers. Even when thus forced on

Figure 86. A company position after approximately 2 hours of work. Note. After approximately 6 hours of work the individual firing trenches within a squad position will be connected, forming a single line.

Figure 87. The company position after approximately a week of construction time (56 hours). Note. Squad positions will be enlarged standing trenches. THe communication trenches will be deep enough for crawling, and the shelters will be of light construction, accommodating 6 men. Only the machine gun shelters will be built to resist 150-mm howitzer fire. The wire entanglements beyond the front-lines will be 8 meters in depth.

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Figure 88. A company position after approximately 4 weeks of construction time. the defensive. Japanese officers have the return to the offensive always uppermost in their minds and are quick to launch counterattacks, large and small, coordinated and uncoordinated, on the slightest provocation. On the maneuver ground, troops are always ready to abandon their prearranged system of infantry fires to meet the attacker with the bayonet in front of their trenches. The defects of a defense so conducted are glaring to the occidental student of tactics, but its positive and aggressive character has virtues which will, on occasions, upset a careless or overconfident attacker. b. Other characteristics. In spite of the usual instruction issued relative to the need of echelonment in depth of the defense, there is an apparent tendency to concentrate a disproportionate strength in the front line. This is especially true of the special weapons (machine guns, battalion guns, etc.). The appearance of the "broad defense" in Combat Regulations appears to be a recognition of modern infantry, as well as an official corrective to the often remarked Japanese tendency to a should-to-shoulder disposition of units both on the attack and defense. Section IV. RETROGRADE MOVEMENTS 1. THE WITHDRAWAL. a. General. There is little military literature obtainable to elaborate on the bare substance of the provisions of the Japanese Regulations governing the withdrawal. In general, the method of withdrawal appears to be standard. It is notable, however, the usual strong insistence on the dangers of a daylight withdrawal is not in regulations. No information has been obtained as to when the Japanese commander considers a withdrawal required or justified since, in the cases studied, the withdrawal was executed on army order and was not considered as imposed by the enemy. b. Preparations for the withdrawal. The division commander, in anticipation of a withdrawal, first attempts to clear his rear area of supply troops and installations, improves the roads which he expects to use, and orders preparations far demolitions to delay the enemy follow-up. All preparations are made with the utmost secrecy while preserving a bold front. c. Daylight conduct of the withdrawal. (1) Local covering forces. The breaking of contact of the front line infantry is done under the protection of local covering forces, disposed from 1,500 to 2,000 yards behind the firing line. These troops are obtained from battalion, regiment, or other reserves not committed to the front line fighting. The position occupied is, when possible, to the flank of the line of retreat on commanding ground permitting overhead fire in support of the retiring troops. The local covering forces give support by fire and, on occasion, may execute local counterattacks to aid in disengaging the front line infantry. About the equivalent of one regimental sector in open warfare appears to be an average strength for the local covering forces in the problems consulted. (2) General covering force (Shujo Jinchitai). In addition to these local detachments, the division commander organizes a general covering force behind which he reforms the major elements of his command. The division reserve is usually the principal component of this covering force which, in principle, is made up of the freshest troops at the disposal of the commander. The bulk of the division artillery withdraws and deploys behind this covering position to protect the withdrawal. The Japanese

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try to place the covering position at an oblique angle to the axis of retreat and from 3,000 to 5,000 yards in rear of the front line. The division command post is set up behind the covering position for the purpose of controlling the withdrawal and organizing the subsequent retirement for which the troops on the covering position eventually become the rear guard. (3) Execution of withdrawal. Protected by the covering forces, the front line infantry withdraws straight to the rear assisted by support units in the second echelon. The Japanese feel that it is desirable for all front line units to pull back simultaneously, but often some must hold on longer than others. The division artillery, the bulk of which already has retired to the general covering position, supports the withdrawal. In some sectors, a sudden local counterattack may be warranted in order to create a favorable situation for the withdrawal. Retreating units reform progressively, arriving by many small columns in the general assembly area behind the general covering position. Here, division march columns are formed and directed toward the final terrain objective of the withdrawal. The engineers execute demolitions to retard the enemy, while columns move off covered by a rear guard. The cavalry and aviation reconnoiter for turning movements around the flanks by pursuit detachments. The aviation may be called upon to attack ground troops which are endangering the success of the withdrawal. d. Night conduct of withdrawal. (1) General. The night withdrawal differs from that in daylight in the following important respects: a. The local covering mission is performed by a "shell" of small detachments left in position on the front line throughout most of the hours of darkness. b. Retiring units reassemble and form march columns nearer the front line than is the case in daylight. c. A general covering position is ordinarily not organized. Detailed preparation in daylight is necessary prior to a night withdrawal. This includes a designation and marking of roads to be used by retiring units, as well as the usual clearing of the rear area. Secrecy is essential throughout to conceal the intention to withdraw. (2) "Shell" The breaking of contact by the front line infantry is done under the cover of a thin line of infantry detachments, strong in machine guns and supported by a small amount of artillery. This "shell" simulates the usual sector activity throughout the night to deceive the enemy and, if attacked, sacrifices itself in place to protect the retirement. Its time of withdrawal, usually about daylight, is set by the division commander. The mission of the "shell" may be facilitated by local attacks executed early in the night by front line detachments prior to their withdrawal. Normally no general covering force is needed to supplement the "shell." An exception is the case where the "shell", left in place until dawn, requires protection to get away without undue losses. In such a case, a small general covering force, strong in cavalry and mobile troops, may be organized for the. benefit of the "shell." (3) Execution of withdrawal. The behavior of the front line units is essentially the same as in daylight. They reform progressively as they retire, assembly areas being somewhat nearer the front line than in daylight. One or two companies of artillery remain until nearly dawn to support the "shell" and carry out normal activity. e. Comment. Japanese procedure in the withdrawal is generally orthodox. The absence of the customary injunctions against the daylight withdrawal is symptomatic of the Japanese under-estimation of the effects of modern fire power and aerial attack. However, it is unwarranted to assume that, in practice, they will not try to avoid daylight withdrawals when the situation permits. 2. THE DELAYING ACTION. (JIKYUSEN). a. General characteristics. (1) The Japanese do not recognize the delaying action as a separate and distinct form of military operation but include it in the broader term, "jikyusen" (holding-out-combat). The expression is used to cover, in addition to pure delay, a number of types of operations characterized by a desire to avoid a fight to a finish, but in which the idea of delay is somewhat remote. Thus, in addition to the typical delay situations, such as the action of rear guards and covering forces, the Japanese treat under "jikyusen" demonstrations, reconnaissances in force, and night attacks designed to cover a withdrawal. In the subsequent discussion, an effort is made to disregard the elements not bearing directly on delay which the Japanese inject into the treatment of "jikyusen." (2) The usual purpose of delaying action is to gain time to contain or to divert a superior enemy while avoiding decisive combat. "Although these ends are frequently achieved by defensive action, there are occasions when the mission can be accomplished only by offensive action." The preceding sentence is a literal translation from the Sakusen Yomurei. Elsewhere, the same regulation urges that even when defensive measures are initially better adapted to the situation, the commander must always be ready to take advantage of an opportunity for offensive action. However, when offensive action is indicated, in order to avoid becoming deeply engaged, the division commander designates limited objectives and rigidly controls the number of troops committed to action. In comparison to the meeting engagement, fronts of deployment are wide in such an offensive action. (3) Mobile troops, well equipped with automatic weapons and artillery, are best adapted to delaying actions. The infantry fire fight generally takes place at long ranges as the engagement is broken off when the enemy draws near. Frontages are wide, and the breadth is obtained by increasing the intervals between occupied key positions. Reserves are kept large to cover withdrawals, to give continuity to

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the resistance of the delaying force, and to provide troops for such limited offensive actions as the commander may undertake. b. Choice of a delaying position. While the situation may force the commander to seek the required delay on a single position, such a disposition creates a danger of becoming involved in a fight to the finish or in a costly withdrawal at close range from the enemy. It is thus preferable to delay on successive positions separated by about two to three miles. A delaying position is chosen for its observation, distant fields of fire, and covered