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

[Intelligence Bulletin Cover]  
The following report on Japanese ground forces was originally published in the Intelligence Bulletin, October 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.]



a. Tactics

(1) Infantry.--As a rule, Japanese infantry in the Philippines started their attacks just before darkness or at night. In nearly every case, the attacks were flanking movements carried out by forces ranging from individual snipers to fairly large groups of soldiers. These groups worked separately, not worrying about the men on their right or left. They sneaked around the flanks or through gaps, and then imitated bird calls so that they could detect each other's whereabouts and meet. Regardless of the opposition encountered, these men maintained an aggressive effort to accomplish their mission. They tried to clear out certain designated areas during the night and have them completely occupied by dawn. Usually the attacks were made on small fronts of about 1,000 yards. Sometimes the infiltrating groups, behind or to the flanks of our lines, would remain quiet for 2 days or more while other groups infiltrated through to strengthen their positions for attack. These tactics were successful mainly because of the jungle country, and because the Japanese had the most troops and complete air superiority.

The Japanese made good use of a .25-caliber light machine gun, which was easy to handle in the jungle. The gun often was carried strapped to the back of one man, who acted as the bipod when the gun was fired, while another man with him acted as gunner. When a target was observed, the first man flopped to the ground, with the gun on his back, and the gunner flopped behind him and fired the gun. As soon as a clip of ammunition was fired, they would roll over, 10 yards or more, and open again on the same target. By repeating this several times, the Japanese tried to lead our troops to believe that two or more machine guns were operating against them. At first, some of our troops believed that this .25-caliber was a Tommy gun.

The Japanese sniper wore a split-toe, rubber-sole ankle-shoe, which had a cheap cloth top. He wore a headnet cover over a steel helmet and a loose shirt or smock, which had several patterns of green and white colors in wavy lines.

One apparent weakness of the Japanese in jungle tactics was their practice of throwing their full strength into the battle at the beginning. This method worked all right when it succeeded in driving back our forces. Such tactics would be dangerous if the opposition were to hold and counterattack strongly.

(2) Artillery.--The Japanese handled artillery very well, except that at the beginning they showed they were not used to combatting opposing artillery. They did not conceal their guns, and they moved forward with truck columns under artillery fire or tried to occupy a town within U. S. artillery range. However, the Japanese learned quickly from experience, although only after suffering heavy casualties.2 Although their fire generally was effective, it never was very heavy except just before the fall of Corregidor. The Japanese concentrated artillery on Bataan after it fell, and plastered Corregidor heavily with the aid of an observation plane and observation balloon. Their 150- and 105-mm guns were the most effective weapons in the bombardment, although a few 240-mm guns were used.

The Japanese battery included a fifth gun. While four guns were firing on a target, this fifth gun would fire on a new target to get the range and make other firing adjustments. So, when the battery had completed fire on a given target, it had all the fire data on a new one and could begin heavy firing at once.

(3) Chemicals.--The Japanese used no smoke or poisonous gas. They attempted to burn the woods on Bataan without success.

(4) Refugees.-—The Japanese destroyed considerable civilian property at the beginning of the war to force refugees into our lines. Between 10,000 and 30,000 refugees flooded Bataan, adding greatly to our supply problems.

b. Equipment

(1) Rifle.--The .25-caliber rifle was the only one used by the Japanese. Much lighter than our Grarand, it was ideal for jungle fighting. In contrast to our rifle, the Japanese weapon gave no flash and did not make a loud noise. Use of smokeless powder by the Japanese in their rifles—as well as in their machine guns- gave them another advantage over us. Our Gar and proved 100 percent effective, although a little heavy for jungle use.

(2) Machine guns.--These were of three types--calibers .25, .30, and .50. Their .30-caliber gun is heavier than ours and was not particularly suited for jungle warfare.

(3) Grenades.--Two types of grenades were used, a small and a larger size. Some of these were fired from small mortars which weighed from 5 to 10 pounds.

(4) Mines and traps.--The Japanese were cunning in the use of antitank mines on trails. They had plenty of mines and used them on all probable tank approaches. They also resorted to the old jungle trick of fixing grenades on twigs and branches over trails. "Doped" food and cigarettes were dropped in places where our troops would be expected to find them.

(5) Tanks.--The Japanese had a large number of small tanks in the Philippines, but they used them extensively only at the beginning of the war and near the end of the campaign. The tanks had a "V" front, and this sloping armor made them a hard target to hit solidly from the front. A good place to hit them is on a flat surface just below the "V" front. The tanks were well constructed.

(6) Artillery.--The Japanese used 47-mm antitank guns, some 75's, 105-mm guns, 150-mm guns, and a few 240-mm siege guns. The 47 's stood up better than our 37's, and the 105's and 150's proved to be excellent weapons.

(7) Personal.--Leather equipment rots rapidly in the jungle because of the moisture, while webbed articles stand up well. Raincoats are greatly needed. All articles, such as mosquito nets and towels, should be green or brown.


The Japanese have been playing "straight football" in China, leaving off the trick devices used in Malaya and the Philippines. Usually they throw almost everything into the front lines to start a battle and withhold very few reserves. Pursuit is their specialty, and they prepare pursuit columns at the time of the attack. On the front they organize a holding battle and later place their main efforts on one or both flanks. Then the pursuit column goes into action, usually with tanks and other motorized vehicles. These columns generally push far ahead of the main body.

Smoke has been used freely by the Japanese in China, and some poisonous gases have been employed on a small scale.

Japanese rifle fire, .25-caliber, has not been very accurate when judged by our standards, and their pistol marksmanship is considered "lousy."

Very few tanks are used because gasoline has been hard to obtain.

As in Malaya and the Philippines, the Japanese use mortars and grenades to great advantage.

Considerable attention is devoted to camouflage. Every man has helmet and body nets, and all artillery units have nets for their pieces.

1 Practically all the information given in this section was obtained from United States military observers who were on the battlefronts involved.
2 Our artillery killed as many, if not more, Japanese than did all the rest of our weapons. The total Japanese casualties were much higher than ours, but ours were comparatively low. Most of our casualties were from small-arms fire.


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