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"Ground Forces (Japan)" from Intelligence Bulletin, September 1942

[Intelligence Bulletin Cover]  
The following U.S. intelligence report on Japanese ground forces in WWII was originally published in the Intelligence Bulletin, September 1942.

[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 Japanese must be recognized as vicious enemies who are highly trained and exceptionally well organized. They have proved themselves formidable foes in battle. Their calculated advances, successfully carried out, have shown them to be masters of detailed planning and execution of policies.

Nevertheless, the early successes of the Japanese were not the result of brand-new tactics or new super weapons. Basically, their tactics are no different from those employed by other modern armies and their equipment is, as a whole, inferior to that of the United Nations. They had large numbers of experienced troops and large amounts of equipment' ready when they struck their first blows. They were much closer to the areas of battle than the bulk of our forces, and they had the added advantage of striking with surprise and getting the "jump" on all the fronts. In addition to these advantages, the Japanese modified their basic tactics to adapt them to jungle conditions. Their operations were carried out with great speed and deception. Thorough reconnaissance usually was made ahead of each operation, and communications were well coordinated down to the lowest units. Camouflage, Fifth Columnists, and deceptions were widely used. The Japanese found in many instances that bluff was cheaper than force.


a. Movements

The fast movement of the Japanese during their early successes in the tropical battle areas was made possible by their physical stamina, light equipment and armament, as well as the use of all means of transportation and the aid given them by Fifth Columnist guides. They rode trucks and trains when possible, they obtained bicycles and small boats from the natives, and they swam streams when no other means of getting across were available. They made the fullest use of captured trucks, tanks, guns, and ammunition which were taken intact, or only partly destroyed. They quickly repaired the latter and used them. In addition to the boats obtained from the natives, the Japanese brought with them specially-designed small river boats to assist their movements. These they used often in Malaya and Burma to infiltrate patrols to the flanks and rear of defending forces. The patrols generally moved silently and at night.

The Japanese have used air transport planes both for personnel and supplies, but not on a large scale. It is known that they have trained air-borne troops.

b. Infiltration

(1) General.--The Japanese used infiltration tactics to great advantage in conquering the jungle areas now in their possession. This kind of attack is well suited for jungle warfare, especially when the attacking forces have more troops than the opposition. And in nearly every place where they fought during the first few months of the war, they were able to mass a much larger force than the United Nations.

There was nothing particularly new about the Japanese infiltration tactics. The principles they used are practically the same as those set out in our Basic Field Manual on "Jungle Warfare" (FM 31-20). Our methods of defense against infiltration, as given in FM 31-20, when properly carried out, are considered the best basis for combatting the Japanese.

(2) Methods Used.--Usually the Japanese avoided attacks to the front of United Nations forces, except in cases where the enemy sought to deceive our troops. The frontal attacks generally were made with a comparatively small number of men. These were armed with light machine guns, which were fired at a rapid rate in order to make our troops believe a much larger force was attacking. Also, on numerous occasions, the Japanese set off firecrackers to add to their efforts to confuse.

Regardless of whether these frontal attacks were made, the Japanese nearly always moved patrols around the flanks of our forces, and, in many instances, patrols crept through gaps in our lines to reach the rear. The patrols usually were small, numbering from two to a few dozen men. They were lightly dressed, and generally were armed with light machine guns and grenades. Each of the men carried enough compact food to last for several days. By collecting food from the countryside, they often had enough to last much longer. These men had been trained and hardened to withstand many discomforts. All, or nearly all, were expert swimmers and handlers of small boats. They had been instructed to look upon woods and water as things to assist them--not as obstacles.

The infiltrating Japanese patrols had various missions. In all cases camouflage was widely used, and all movements were made as silently as possible. Some of the Japanese who acted as snipers painted their faces and hands green to conform to the leaves of the trees and covered their clothes with leafy branches. Others dressed as natives or in uniforms of opposing forces. Many of them climbed trees and tied themselves with ropes so they would not fall out if they went to sleep or were wounded. In many instances they were accompanied by Fifth Column guides. The sniper's equipment included the following:

Gas mask, green combination mosquito net, camouflage hood covering his helmet, head, and shoulders; green corded net to camouflage the rest of his body; black wire eye-screen for protection from sun glare; coil or rope to use in climbing and tying himself to trees; a small sack of rice; small bag of hardtack; one-half pound of hard candy; package of concentrated food; can of field rations, can of tea; can of vitamin pills; can of chlorine to purify water; mess kit; canteen; a treatment for mustard gas; quinine; stomach pills; gauze pads, roll and triangular bandages; spare socks; gloves; toothbrush; flashlight with rotating lenses of different colors (one color apparently to be used as a recognition signal), and six spare lenses for eyeholes of gas mask (some usable in subzero weather).

Besides sniping, other missions performed by the infiltration groups were: to carry out reconnaissance, disrupt opposition telephone lines and block roads, destroy command posts, and create confusion in the rear of opposing forces. This last was one of the most important missions. The Japanese would withhold their fire until they got behind, and to the sides of, United Nations forces. Then they would open up with the rapid firing of light machine guns, and, frequently, with the explosion of firecrackers. Sometimes great batches of firecrackers were dropped from planes, with a lighted fuse to explode them after they fell. By giving the impression that large numbers of their troops were attacking, the Japanese tried to force quick withdrawals in the hope of capturing large amounts of weapons, trucks and other vehicles, supplies, and men. Often the Japanese opened fire for the purpose of drawing fire from the opposing forces so that their positions could be located. The Japanese then would attack the positions with mortars, or infiltrate between our positions.

In their infiltration tactics, the Japanese moved fast at certain times and very slowly at others. They stood in rice-field ditches for hours, up to their necks in water, waiting for targets to appear. They lay hidden in underbrush for long periods waiting for chances to advance without being seen.

Often when the opposition counterattacked, the Japanese hid until opposing troops had passed, and then fired on their flanks and rear.

On some battlefronts the Japanese fortified their positions after infiltrating through and around the opposition flanks. These positions were prepared for all-around defense, and they included an unusually large number of foxholes with connecting trenches. The positions for the foxholes and trenches often were chosen to take advantage of cover, such as logs, rock piles, tree stumps, and roots. Light artillery, radio equipment, and large amounts of ammunition were found buried near a large number of the defensive positions. Once they were entrenched, the Japanese were hard to overcome.

c. Magnetic Mines

A relatively small number of Japanese soldiers in foxholes are equipped with magnetic mines. They attempt to attach these to the bellies of tanks which go over the foxholes. The mines are timed to explode shortly after the tanks pass over.

d. Use of Light Machine Guns

The Japanese have a light machine gun of .25 caliber which they sometimes use in the following way:

One soldier carries the machine gun on his back and stops and leans forward when a target is found. Another soldier immediately behind him shoots the gun. This weapon has a handle attached to it and can be carried like a handbag.

e. Mortars

In Burma, the Japanese transported their mortars in ox carts and on pack ponies. Elephants were used in a few instances to carry the heavy 5-inch mortars used by the Japanese. A second type of mortar used was 2 inches in diameter.

The bursting of the 2-inch mortar shell upon impact apparently was very poor. Some burst within 10 yards of United Nations soldiers without any of them being wounded.

To point out targets to mortar squads, the Japanese in Burma often crossed the fire of red tracer bullets. The position over which the bullets crossed was the target area.

f. Landing Operations1

Once the Japanese get a foothold, they follow through their landing operations with great vigor. The first troops to land usually pass directly inland, and they do not immediately try to establish a beachhead. Also, they usually do not land a large force at first. They push forward a constant stream of small forces, under cover of darkness, until enough troops are ashore to harass the defenders from the flanks and rear. Once this harassing causes the defenders to divide their fire, the Japanese begin landings on a large scale and attempt to establish a beachhead.

In one landing attempt in the Philippines, it was found when the first landing boats came ashore that each had been furnished only 6 gallons of gasoline. This amount was just enough fuel to get the Japanese ashore. By this allowance, the Japanese commander made sure that his troops would not get frightened and turn back to the transport ships. They had either to land or else be killed or captured.

g. Japanese "Graves"

Innocent-appearing Japanese graves, reverently and neatly fenced in, do not always contain corpses. Twelve "graves" were opened in an area where a Japanese spearhead had been slashed off. In only one was there a body; in the others was war matériel, which included three 75-mm. guns, two 37-mm. guns, more than 1,000 rounds of ammunition, a dozen combination telephone and telegraph sets, five rolls of telephone wire, and similar matériel.

h. Deception

The Japanese probably have used more deception in the present war than has ever been practiced in any other campaign in history. For the purpose of deception, they:

(1) Used lighted cigarettes, firecrackers, moving vehicles, barking dogs, and other ruses opposite one of the beaches on Singapore Island to lead the defenders to believe that the main attack would be made at that point (actually the first landing in force was made on another side of the island where the defenders were utilizing only small patrols for defense);

(2) Spoke out in English saying, "We give up," but blasted the United Nations troops when they approached to take the Japanese as prisoners;

(3) Talked to each other in English to attract the attention of United Nations troops, making them believe the conversation was being carried on by their buddies, with the result that the unsuspecting soldiers walked into enemy fire;

(4) Attached such objects as fountain pens, flashlights, watches, rifles, helmets, and bayonets to hidden mines and left the objects to be picked up by United Nations forces;

(5) Dropped leaflets from the air and returned soon afterwards to drop bombs on soldiers who came out in the open to pick up the leaflets;

(6) Told Japanese soldiers that United Nations forces would kill them if they allowed themselves to be captured;

(7) Played dead or hid in foxholes until United Nations troops passed, and then threw grenades at them or shot them in the back;

(8) Timed the firing of their artillery, mortars, and grenade throwers to that of United Nations artillery fire in order to create the impression on United Nations troops that their own artillery was falling short;

(9) Came forward with both hands in the air as if to surrender but when at close range they tossed two hand grenades--one from each raised hand;

(10) Flew the American flag on their ships approaching a landing place in the Philippines;

(11) Used a white flag of truce in order to get within close range of United Nations forces;

(12) Took advantage of the difficulty in distinguishing the Japanese from Malayans or resident Chinese by frequently dressing as civilians and hiding their guns until they could spring a surprise attack;

(13) Dressed in British and Dutch uniforms and steel helmets;

(14) Put captured Indian soldiers as a screen between themselves and attacking Indian troops with orders to urge the attacking forces to hold their fire;

(15) Hired civilians to drive private cars to bridges prepared for demolition by United Nations forces so that Japanese hidden in the cars could shoot the troops guarding the bridges;

(16) Made noises imitating frontal fire to attract the opposition while lightly-armed Japanese troops worked around the flanks;

(17) Employed intelligence personnel with advance guards to confuse British native troops by speaking out in Malay, Tamil, Hindustani, Gurkhali, English, or Dutch--depending on the circumstances;

(18) Exploded firecrackers in the rear of defending troops to give them the impression that they were being attacked from the rear;

(19) Rapped bamboo sticks on hard objects to imitate machine-gun fire;

(20) Placed soldiers in an exposed swimming pool to draw the fire of Dutch machine guns so that their positions could be determined;

(21) Called out in Dutch for the whereabouts of the Dutch commander during a night attack and shot the commander when he answered.

i. Fifth Column

The tactics used by Fifth Columnists for the Japanese showed that thorough preparations had been made for this type of work before the war. In order to make our soldiers more alert to Fifth Columnists, a list of the different actions they have taken to date for Japan is given below:

(1) Collected ammunition and other supplies at secret dumps;

(2) Fortified secret positions to hold until the Japanese arrived or to divert United Nations strength;

(3) Collected United Nations uniforms for Japanese use;

(4) Laid explosive charges under vital military works by tunneling from obscure points;

(5) Attached under-water explosive charges to ships and docks;

(6) Fake missionaries or other unsuspected persons established secret radio transmitting and receiving stations in places such as cemeteries, abandoned quarries, and houses near airports (the tallest building in Singapore was not touched by Japanese shelling because Fifth Columnists operated a radio station there);

(7) Acted as snipers against troops and police behind the United Nations lines;

(8) Disrupted blackouts by connecting house electric systems to the street lighting lines;

(9) Gave signals at night by use of rockets, torches, colored lights, and burning haystacks and buildings (some of these signals were given from hideouts in chimneys, holes in roofs, hollow trees, and from the tops of tall buildings);

(10) Hid Japanese troops in their homes until late at night when surprise attacks were made on United Nations forces;

(11) Served as Fifth Columnist organizers while pretending to be newspaper promotion men;

(12) Sabotaged railroad tracks, motor vehicles, and roads;

(13) Used false identity papers;

(14) Used red-clothed scarecrows with arms pointing to United Nations defenses;

(15) Indicated the direction of targets by trampling or cutting arrows in rice fields;

(16) Pointed banana leaves, laundry, or planks to indicate motor transport parks or command posts;

(17) Dressed as British and Indian soldiers and called out to the British not to shoot;

(18) Furnished local food supplies;

(19) Used fishing boats and lights to aid in landing operations;

(20) Indicated airdromes with strips of cloth or paint and by flashing lights;

(21) Acted as expert guides for Japanese troops;

(22) Supplied information gathered before the war by local Japanese residents;

(23) Gave assistance while serving as native officials;

(24) Cloaked themselves as priests or monks to do Fifth Column work;

(25) Obtained small boats for Japanese infiltration parties;

(26) Tampered with air-raid warning systems to make them unworkable;

(27) Spread rumors among native troops;

(28) Drew up airdrome plans to turn over to the Japanese--a Malay overseer at Alor Star airdrome, Malaya, was arrested with airdrome plans, signaling apparatus, and Japanese propaganda;

(29) Used rice, salt, and white paper on roads to denote presence of opposing troops;

(30) Aided in the organization of the "Free Burmese Army";

(31) Obtained information direct from United Nations airfields--possibly by transmissions from nearby undetectable short-wave radio sets2 to adjacent field transmitters and then to Japanese air headquarters;

(32) Distributed propaganda pamphlets dropped from the air by the Japanese;

(33) Signaled to Japanese aviators by placing lights in hollow stumps where they could not be seen from the ground;

(34) Placed "puncture traps" on Burma roads to damage or delay United Nations motor transports. (The traps consisted of several sharp steel spikes, cut out of 1/4-inch flat steel sheeting. The spikes were 6 inches long, with the upper 3 inches protruding from the road bed and camouflaged with mud, straw, or dried leaves).

(35) Two coolies walking together, one wearing a red shirt and the other a white, indicated that opposing troops were in the area;

(36) Soft drink sellers on bicycles signaled to the Japanese with a flag, waving it twice and pointing to British troops--after having served the British free drinks;

(37) A German dressed in civilian clothes walked in front of Japanese patrols by 50 yards and engaged opposing troops in conversation while the patrols took up firing positions;

(38) Telephone operators acted as chief Fifth Columnists in the Kedah, Malaya, area;

(39) Members of the Thakins Party, an anti-foreign political faction in Burma, organized to resist the British by Fifth Column activities and by joining the Free Burmese Army;

(40) German missionaries in New Guinea turned out to be Fifth Columnists--they helped the Japanese through the jungles to contact Australian forces.


a. Rifles

All Japanese rifles captured to date are of .25 caliber--quite a bit smaller than either our Garand or Springfield. The Japanese use both long- and short-barreled .25-caliber rifles. The barrel of the short type is four-fifths as long as that of the long type. The sling of the short type is attached to the side of the rifle instead of underneath, as in the case of the long type. The short rifle is used by engineers and signal corps men. Both rifles have detachable bayonets.

b. Swords

Japanese officers and noncommissioned officers often carry a long curved sword, which is used in combat.

c. Helmets

These are a muddy brown color and are shaped somewhat like a large bell. They are lighter in weight than our new type helmets and provide less covering protection. The Japanese helmet fits inside a tropical hat of similar shape. The hat has a camouflage net, which the Japanese usually cover with grass, leaves, or other natural covering.

d. Shade

To keep dust from their eyes, some Japanese soldiers wear a black screen shade, 7 inches long and 2 inches wide. The shade fits across the face, above the mouth and over the eyes. It is held in position by a string tied back of the head.

e. Entrenching Spades

More than one size is used. One type has a 10-inch handle and an 8-inch blade. A larger spade has a handle about 32 inches long. The blade of this spade has two peep holes through which the soldier observes from the top of a trench or a rise in the ground. The blade covers the soldier's face while the rest of his body is hidden in the trench. The blade also has a bulge for the soldier's nose, like a Hallowe'en mask.

f. Water Purifier

The Japanese are instructed to boil their drinking water when there is any doubt as to its purity--if this can be done. In combat situations where drinking water cannot be boiled, a purifier tube is provided. The tube, made of rubber, has a purifying device at the end from which the soldier drinks. The device consists of two cloths, one of which contains purifying chemicals. The second cloth is used to remove the taste of chemicals from the water.

g. Rope

Each Japanese infantry squad carries a piece of rope 70 feet long.

h. Diaries

A large number of Japanese soldiers keep diaries. If you find these on the battlefield, be sure to give them to your unit commander. They will then be translated because they may contain valuable information about the enemy.

i. Wire-Scaling Device

The Japanese have a long "rug," made by putting pieces of bamboo together, which they throw over barbed wire so troops can get over the wire without having to cut it. While the rug is being carried from place to place, it is rolled up so it will be easier to transport.

j. New Bomb

The Japanese recently introduced a new type of bomb for use against aircraft. The bomb is pear-shaped and is designed to explode in the air. When it has been regulated to explode at a given time, it is released about 1,000 feet above and to the front of our planes. The explosion produces a bright purplish light with white smoke streamers.

1Further details on Japanese landing operations are given in Information Bulletin No. 16, Japanese Warfare: A Summary, dated May 20, 1942, and published by the Military Intelligence Service.
2These sets were believed to be small, portable transmitters of such low power that they were not detectable at the United Nations airfields, but of sufficient strength to be received by nearby field receivers. Messages received from the small sets were then relayed by more powerful field transmitters to Japanese Air Headquarters.


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