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"Japanese Warfare—From Their Documents" from Intelligence Bulletin, March 1943

[Intelligence Bulletin Cover]  
The following translated excerpts from Japanese documents were published in the Intelligence Bulletin, March 1943.

[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.]



This section is based on various types of Japanese documents, obtained from several sources. They have been arranged according to subject matter as far as possible. Some are given almost verbatim, while others have been edited to eliminate repetition and parts considered of little or no value. The individual documents are separated by the use of dashes.


a. During the Day

Although it is said that the jungle is ideal for the individual soldier, if he does not carry woodcutter's equipment he will often find it impossible to get through. Although the density of jungle varies, a woodcutting group of 20 to 30 men under the direction of an officer is necessary for a single column (one team under the man in charge of blazing the way, and several teams under the man in charge of cutting through).

Speed in passing through jungle will depend upon its density, but in general 1 kilometer (5/8 mile) will require 2 hours.

To maintain direction, a compass should be used; even so, mistakes in direction are sometimes made because of the tendency to keep following the easiest terrain. Moreover, the magnetic declination on Guadalcanal Island must not be forgotten; that is, to advance west by compass, one must advance approximately 7°40' northwest. Therefore, it is important to search out the highest ground possible and orient one's self before proceeding.

For bivouacking in a jungle, the foot of a slope is best because it has cover from bombing or strafing. The area around streams might easily be a target for enemy planes, and so is not suitable.

Use such things as small whistles to keep contact in the jungle, but do not shout carelessly, especially at night. On high ground in the jungle, the enemy has installed microphones to learn of our approach and make it possible to bombard us. Often it is impossible to get artillery pieces through the jungle unless they are dismantled.

In the jungle the Americans build individual shelters, surrounded by wire entanglements, or concealed; and, when we approach, they fire tracer bullets or signaling shots to direct bombardment.

In grass plots in the jungle, the enemy sometimes prepares a concentration of fire. It is especially important to search in advance the border areas between jungle and grass plots.

The enemy is extremely well equipped with artillery and heavy infantry weapons, and, on seeing us advance, they freely open up with heavy fire. Therefore, in advancing through open country by day, it is important to cooperate well with our own artillery.

When the enemy discovers even an individual soldier, whether by day or night, they bring concentrated fire on him. Make use of this by causing the enemy to waste his bullets. That is, place imitation targets where troops are not disposed, and at night carry out such clever deceptions as lighting lamps.

In the jungle there are covered machine-gun emplacements at unexpected points. If the first line of troops discovers them, they must take measures to destroy them immediately.

The enemy has few tanks and they are slow, so they can easily be destroyed by such weapons as our rapid-firing gun and infantry gun.

The enemy greatly fears our assaults. Do not forget that final victory always lies in hand-to-hand battles.

b. At Night

Movement within the jungle at night, especially the movement of large units, is extremely difficult. When passing through the jungle at night, even when the course has been marked and plotted during the day, contact is often lost, especially front to rear. Therefore, it is essential to devise means of maintaining contact, such as the use of punk (made from coconut husks), fireflies, and phosphorescent substance (from decayed trees).

As the organization of fire by the enemy is precise, even at night, care must be taken to deploy to such an extent that the control of command will not be impaired. It is important to keep from giving the enemy an opportunity to fire, by making use of terrain features, camouflage, and crawling, and at the same time to devote one's efforts to continuing the advance.

The foremost prerequisite of success is that each unit reach the objective of its attack, and maintain the prescribed direction of advance. It is extremely important to avoid mixing the units of a force, and to keep friendly troops from attacking each other. Therefore, conspicuous landmarks in the jungle area, especially within and in front of the enemy positions, should be previously designated, and it is essential to make the utmost effort to maintain direction by use of the compass, by orientation from high ground, and by every other method.


The terrain within the enemy positions is generally flat, with the exception of the Lunga River area, and traffic is unrestricted. Therefore, within the positions, expect attacks from enemy tanks, covered machine-gun positions, and, at times, concrete pillboxes in the second- and third-line positions.

As a counter measure, prepare hand-to-hand fighting (demolition) squads of infantry and engineer troops, and advance them to the foremost lines. Do the utmost to inflict a surprise attack, and bring up light and mobile guns (presumably light artillery) near the first lines. If conditions permit, have the demolition squads precede the first-line infantry to make the advance of the infantry easier.

It is important to strengthen the shock troops, and to make sure that these troops, by the use of terrain features and camouflage, reach the flank and rear of the enemy firing point and attempt a sudden penetration. At such times, the enemy attempts to fire pistols and throw hand grenades at the nearest of our penetrating troops; therefore it is necessary to penetrate by throwing hand grenades in order to hold the initiative.

Upon occupying enemy positions, it is imperative to pursue the fleeing enemy immediately. By halting, on the other hand, heavy losses from enemy fire might easily be incurred.


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