Some British Observations of Japanese Tactics, WWII Tactical and Technical Trends, No. 26, June 3, 1943 (Lone Sentry)

From a very recent British report, the following observations on Japanese tactics have been selected. Quite possibly, some or many of the details are already known to our troops, but there appears to be much of general interest in these notes. It is worthy of mention that the British are making use of our experience as we are of theirs.

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a. A Hint about Pass Words

The old Japanese trick of using the language of our troops to try and discover our positions has again been used in Burma.

One voice was heard shouting in Bengali "Don't shoot, we are the -- Rifles. Where are you?" On other occasions English and Urdu (a Hindu language) were used.

It is, however, generally quite simple to distinguish whether friend or foe is calling, as the Japanese find many of our words impossible to pronounce correctly.

The following short table indicates the manner in which the Japanese would pronounce certain groupings of English letters. Note that they substitute "r" for "l," "su" or "za" for "th," and "b" for "v."

Words employing any two or all of the letters would certainly be mispronounced by Japanese. It is useful to bear this in mind when formulating pass words.

English Letters         Japanese Phonetic Pronunciation

  La Rah (soft r)

  Ly Rye (soft r)

  Th Su (soft s as in "soft")

  The Za or Zeh

  Very Bedy (y like double "e" in "see")

  Velvet Berubet

b. Reconnaissance Methods

A number of Japanese documents from fighting areas show how the Japanese stress the importance of reconnaissance.

Scouts are instructed to sketch hostile dispositions from observation posts and to bring back their reports without taking any unnecessary risks. Urgent reports, it is stated, must be made by telephone or orally and afterwards confirmed by sketch maps. In reconnaissance much use is made of all available natives.

In New Guinea the primary task of reconnaissance was the pinpointing of positions: personal reconnaissance by officer patrols took place. Preparations for night attacks in Guadalcanal included the sending out of scouts "since enemy security during the night is not always sufficient." Officers were ordered to "study aerial photographs and reconnaissance reports in detail, remembering outstanding features in the area to be attacked."

c. Approach through Jungle

The following extracts from a divisional order secured in Guadalcanal illustrate the detailed precautions taken by the Japanese when approaching a combat area.

"Even though the march through dense forest at night is planned beforehand, there are naturally many occasions when maintenance of contact is difficult. For this reason, during movement at night lights should be used. It may be necessary to use glow worms taken from dead trees to maintain contact.

"If one man is ordered to carry out the work of cutting away the undergrowth through the dense forest, the march will be impossible. A squad of 30 men and an officer is necessary as a clearing squad under jungle conditions to keep the column moving.

"Contact in the forest must be maintained by the use of a small whistle, and it is very important not to shout. The enemy often sets up a microphone on elevated ground and directs his artillery fire when our position is known."

d. Camouflage

In certain instances, gun emplacements have been camouflaged by building up the sides of a gradual slope and coloring the whole position to correspond with the sand or soil surrounding it. The tone blending is complete, but the circular outline remains clearly visible. Overhead covering is not used on this type. In other types, overhead covers are used, the cover being a "flat" made up of a net interlaced with cut scrub. The position is none the less easily observed because of signs of activity on the trails and the tendency of the Japanese to cover only the area immediately over the gun. They also neglect to bridge the "slashed" area in the virgin scrub, which surrounds the emplacement.

In one area our troops found four well-camouflaged guns. Here, a net interlaced with garlands and strewn with small bushes to give relief was used to hide the guns. However, they were readily discernible on photographs because the camouflage did not form a complete cover. The ground surface could be seen, and the light sand, where the emplacement had been dug, revealed its position.

Dazzle painting is another form of camouflage used. The general procedure has been to paint the roof and sides with wavy zebra-like stripes of alternate light and dark colors. Usually, bands of dark and light stripes continue from the eaves, but some roofs are painted with a band of light and dark stripes up to the ridge, and with the contrasting colors from the ridge down to the opposite gutter. This latter method forms a distinct line of demarcation along the ridge of the roof and destroys the illusion. These bands do not average more than 10 feet wide; regardless of the length of the building. Another type of dazzle painting is to paint the roof and sides with spots of dark color on a light background, in a manner that can best be compared to the spots on a giraffe.

The Japanese have been relatively successful in hiding some objects by completely covering them with earth. They have guarded against detection by building a slope of low gradient, thereby achieving the minimum relief.

e. Defensive Bunkers

(1) General Remarks

The Japanese are evidently exponents of the theory that the construction of a defensive position involves a continual process of development. It is normal for a new defensive position first to take the form of a series of fox-holes, which are subsequently, if time and circumstances permit, linked together into a coordinated defense system. Such a position may well include still other fox-holes, which are difficult both to locate and to eliminate. The third stage of development takes the form of the construction of strongpoints, or "bunker" type earthworks as they have been called in New Guinea. These strongpoints, as seen in Burma, fall into two types, both of which are illustrated in the accompanying sketch.

(2) The Double-Bay Bunker

These are built in two sizes, 25 ft. by 15 ft., and 60 ft. by 40 ft. They consist of mounds of earth from 5 ft. to 12 ft. in height, with a rear entrance well recessed into the mound. Forward, a central, apparently solid, block projects to form two bays. These bays vary in size. The smaller-size earthworks form part of the main trench system, with which they are linked, but the large "bunkers" appear to be isolated.

(3) The Single-Bay Bunker

This consists of a roughly circular mound of earth about 25 ft. in diameter and 5 ft. high, with entrance at the rear, opening on to a crawl trench or the main trench system. In front is a firing-slit at, or slightly above, ground level, from 6 to 8 ft. long and about 1 1/2 to 2 ft. high. Inside there is presumably a timbered dugout partly below ground level.

[Single-Bay and Double-Bay Japanese Bunkers

Comment: Up to now these bunker strongpoints have been identified in Burma in beach defense positions only, though there seems no reason to think that they cannot be equally well employed elsewhere should any particular position warrant such a comparatively elaborate defense.

It appears that these defensive positions are normally occupied in the first instance by a platoon armed with their usual weapons--light machine guns, rifles, and grenade dischargers. A position covering a front of some 600 yards may seem a very large assignment for one platoon, but this wide dispersion seems to be standard Japanese practice in the defense.

In the later stages of development of a position, when the strongpoints have been constructed, the platoon is probably strengthened by detachments from the machine-gun company or battalion infantry gun platoon. They appear to use both the single- and double-bay bunkers as positions for their heavy machine guns. The double-bay type may also be used as covered emplacements for their antitank guns. This does not preclude the use of either type also as positions for the normal automatic weapons of the platoon.