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"Notes on the Japanese—From Their Documents" from Intelligence Bulletin, October 1943

[October 1943 Intelligence Bulletin Cover]  
The following is a U.S. intelligence report on Japanese WWII tactics translated from various Japanese documents. The report originally appeared in the October 1943 issue of the U.S. Intelligence Bulletin.

[DISCLAIMER: The following text is taken from the U.S. War Department Intelligence Bulletin publication. As with all wartime intelligence information, data may be incomplete or inaccurate. No attempt has been made to update or correct the text. Any views or opinions expressed do not necessarily represent those of the website.]



The information in this section has been paraphrased from translations of a variety of unrelated Japanese documents. These have been edited to eliminate repetition and passages of doubtful value. The reader must keep in mind throughout this section that the information comes from enemy sources, and that it must not be confused with U.S. methods of warfare.


a. General Comments

This is war, and casualties are unavoidable. Our soldiers must not let themselves be stunned into a passive state of mind by the sight of casualties; each man must resolutely continue with his appointed duty.

During the course of battle, no commander will retreat except upon orders of a higher command. No unit will take action on its own initiative. No commander will oppose the plans of his superior, or lower the morale of his unit. Casualties result from misunderstanding one's mission, or failure to give proper orders. Further casualties result because lower commanders often lack self-confidence, or desire notoriety. [Editor's note: According to some earlier notes on Japanese training, considerable emphasis was placed on the initiative and daring of small-unit leaders. Perhaps some of the latter have overstressed the point.]

If the enemy situation is completely unknown, we will not make a frontal assault.

Hand-to-hand combat during daylight hours is not advisable. It is not profitable to be foolhardy, because modern war involves tremendous fire power, with automatic guns.

b. Reconnaissance

Items which you [Japanese] will note while reconnoitering in the jungle include the following:

(1) The size of the jungle and the nature of the foliage around its edges;

(2) The nature of the terrain covering (density of plant growth, types and sizes of trees, and the condition of fallen trees);

(3) The nature of defiladed positions and the degree of defilade;

(4) The nature and condition of the terrain as a whole, including streams, marshes, cliffs, and other ground obstacles;

(5) The deviations on the compass, if any, and the accuracy of available maps or other reference material;

(6) The communication installations, if any; the condition of any inhabited areas; and any problems in connection with water supply;

(7) The degree of infestation by mosquitoes, flies, and other harmful or nuisance insects;

(8) Whether or not the area is occupied by enemy [United Nations] security detachments, positions, or defense installations; and

(9) Suitable routes for the advance of all columns.

During the advance, in jungle areas, make a complete reconnaissance of the enemy situation. In addition to sending out patrols, each unit will select competent personnel (those with excellent eyesight, such as fishermen and the natives of Ponape Island) for close-range reconnaissance.

In the jungle, the individual soldier on reconnaissance should constantly be on the alert for the slightest movement or sound. He should advance only a short distance at a time, making use of the terrain and foliage and crouching as much as possible. When resuming reconnaissance after resting, he should go forward and retreat a number of times. If an individual enemy is discovered, creep up and shoot him. Take particular care to guard your rear.

In the case of a small detachment patrolling in thick jungle, one man must go forward with his rifle ready to protect the others. It is also necessary to keep a sharp watch to the rear.

c. Advancing in Jungle

Platoons advancing in the jungle will move by squads, or deploy in two lines, or they will move in a diamond formation led by the leading squad. If hostile forces are known to be far away, there are many occasions when the platoon can move in column formation.

If hostile forces are encountered, concentrate maximum fire power on them, and maintain the advance as they retreat.

The interval between squads depends upon the density of the jungle and the nature of the terrain.

In case of a company advancing through the jungle, one platoon will form the front line, or the platoons will advance in waves. Covering fire will be provided. The direction of advance will be indicated by the leading platoons.

In approaching hostile forces, provide adequate covering fire. When closing with the enemy, it is necessary to lay down intense fire from light machine guns, rifles, and grenades. If this fire is relaxed, not only in the advance held up but the entire tactical situation is jeopardized.

The above precautions are necessary to stamp out the "guerrilla" activities of the hostile forces.

d. Assault Tactics

Consider the following possibilities in connection with launching assaults:

(1) Attract the attention of hostile forces from the front by the use of smoke, by firing, or by shouting; then assault from another direction.

(2) Wait until darkness to assault, particularly if nightfall is only 20 to 30 minutes off.

(3) Make use of rain or fog, and assault when the enemy is off guard.

(4) Assault when the enemy's attention is diverted by our bombing operations.

(5) Assault suddenly over terrain which the enemy believes to be impassable, such as cliffs, rivers, streams, steep inclines, and jungles.

During assaults, be especially careful not to group together at vital points, such as hilltops, villages, and bridges. These are excellent targets for hostile machine guns, artillery, and bombing.

e. Pursuit

Hostile forces during withdrawals always attempt to destroy installations, such as bridges, power plants, airfields, manufacturing plants, and communication facilities. Prevent this destruction by advancing at an unexpectedly fast pace. It is of vital importance to hurry the opposition during a withdrawal.

Where there are no bridges across nonfordable streams, swim across them. Your clothing and equipment will dry quickly.

Watch out for booby traps while capturing hostile establishments. First, cut electric wires to prevent explosions. Arrange for engineers to remove explosives.

f. Antitank Tactics

Some antitank weapons and methods of using them are as follows:

(1) Magnetic mines.—Attach them to the steel plating of the engine section, or to the turret above the driver's seat, because the armor is relatively thin at those places.

(2) Molotov cocktail.—Throw these at the engine section, in the rear of the tank, to set the motor afire.

(3) Explosive with handle.1—Insert the explosive on top of the ground tread, so that the tread will carry the explosive to the front sprocket. Camouflage yourself thoroughly, and then crouch low as you move quickly to insert the explosive and make your getaway.

Favorable opportunities for attacking tanks at close range include the following:

(1) When a tank slows down in climbing a slope or passing over obstacles;

(2) When a tank is separated from other tanks, or from infantry;

(3) When a tank is passing through covered terrain; and

(4) At dawn, at dusk, and at night.

g. Antiaircraft Tactics

As soon as the pilot of a hostile plane sees the flash of the first antiaircraft round, he changes his course. Therefore we should limit each gun to four rounds in the first salvo.

Against fighter planes making diving attacks from several directions, it is effective to fire two types of time-fuze shells with a 1-second difference in the delay element (or more, depending on the situation).

In case a combination of hostile fighters and bombers attack us, we should fire on the fighter planes when they come close. This is particularly important where a bomber [bombers?] is used as a decoy while fighters attack from other directions.

h. Night Combat

The hostile forces have a large number of heavy and light machine guns and automatic rifles. Therefore, a careless assault, even at night, will result in great losses. Each front-line unit will deploy into the most advantageous formation and take every advantage of terrain and cover before assaulting. (For further information, refer to paragraphs 210 and 217 of the [Japanese] Infantry Training Manual.)

Because of the lack of systematic support, our firing power usually fails to achieve much success [in the Southwest Pacific]. In night attacks, prepare for simultaneous firing, even if attacks are not directed at the same objective. Reserve units should be used without hesitation.

i. Precautions with Ammunition

Every effort should be made to keep ammunition dry and cool—not over 90° F. Extreme care is required particularly for shrapnel shells, time and percussion fuzes, and so forth, which contain non-smokeless powder. Valuable opportunities have sometimes been lost because hand grenades failed to explode on account of dampness.

Observe the following points in the handling and use of ammunition:

(1) Keep it from receiving the direct rays of the sun.

(2) Stack it so air can circulate, throughout.

(3) Do not place ammunition directly on the ground. First put down wooden rests, so that air can circulate under the ammunition and protect it from the heat of the ground.

(4) Keep ammunition-loaded vehicles in the shade as much as possible. Improvise awnings made of tree branches to cover the load while in transit.

(5) Stack in the shade or under awnings the supply of ammunition at gun positions.

(6) Be sure there is space for air to circulate on the top and sides of ammunition dumps which are covered by sheets for protection against rain.

Ammunition for all guns will be protected against moisture by pasting a paper in the percussion cap (they may be fired without removing the paper).

Separate the smoke bombs filled with yellow phosphorus from the rest of the ammunition, and stack them in a cool place, out of the sun.

If air should come in contact with the yellow phosphorus, it will produce an offensive smell or a white smoke. The shell will explode unless proper steps are taken. Without delay the shell should be immersed in warm water or smothered with sand.

Signaling shells and special shells will explode spontaneously under high temperature, so keep them cool and clean and separated from other ammunition. (This information applies to the "10th-year model" grenade signal flare.)

In supplying ammunition, make no mistakes as to the fuzes for the different types of bombs and shells. Observe the marks on the fuze boxes or on the fuzes, so you will not confuse the type classifications, such as "Field Cannon," "Howitzer," and so forth. Where the outward appearance of shell cases is identical, or where different types of shells are similar, pay particular attention to the distinguishing markings on the ammunition boxes and the cases so that you will not confuse the types of fuzes for cannon.

When transporting shells, the fuze should be removed from the complete shell, except under the following circumstances:

(1) When a unit transports ammunition loaded in the regulation manner, in the specified boxes and vehicles;

(2) When a special type shell loaded with yellow phosphorus is fitted with a fuze and made completely air-tight;

(3) Where shells were fitted with fuzes when they were manufactured, or were fitted with a base fuze; and under such other circumstances as may be determined from time to time.

j. 6.5-mm Ball Ammunition

We [Japanese] have two types of 6.5-mm ball ammunition, the standard charge and the reduced charge. The standard charge weighs 2.15 grains and the reduced charge 2 grains. As a means of distinguishing between the two types, the mark (G) is stamped on the lower left-hand corner of the top of the box in which the reduced-charge ammunition is packed.

The suitability of these types of ammunition for the various types of 6.5-mm weapons is indicated by the following table:

Type of gun Model 38
(1905) rifle
Model 38
(1905) carbine
Model 3
(1914) HMG
Model 11
(1922) LMG
Model 96
(1936) LMG
Type of
Standard charge. Standard charge. Standard charge. Reduced charge. Reduced charge.
Reduced charge. Reduced charge. Reduced charge. Standard charge
when there is
no alternative.

k. Use of Captured Supplies

When the battle does not progress favorably and supply becomes very difficult, assault and capture enemy supply depots at all costs.

Since the enemy usually burns the supplies he cannot carry during withdrawals, each unit will act quickly to prevent this destruction so we may use the supplies.

l. Treatment of Prisoners (Singapore)

The handling and direction of prisoners of war at work must be still more strict. Subordinates must be trained to bear down and make the prisoners work hard. We have seen subordinates acting toward prisoners as if the latter were on an equal footing with themselves. These men do not know themselves.

Subordinates must have sufficient self-respect to place themselves on a higher level, and use prisoners as if they were Canton [China] coolies. In giving orders, use bugles, whistles, or Japanese words of command, and make the prisoners move fast. Those who lag will be dealt with rigorously, with measures to make them behave exactly as the Japanese Army wishes.

1 This weapon is believed to be an ordinary stick with an explosive charge (probably TNT) attached to one end.


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