The following information on Japanese jungle warfare
is largely based on enemy sources, all of which
are believed reliable. Most of the information was
disseminated by the enemy after he had suffered numerous
reverses in the Southwest Pacific, and therefore
should include some of the latest tactics he has devised
for jungle combat.
This discussion of Japanese jungle warfare is not
intended as a complete study of enemy tactical doctrine
on the subject. It deals largely with information
which has not previously been widely disseminated
among U.S. troops. For a more complete study of
enemy jungle tactics, reference should be made to the
first 12 issues of the Intelligence Bulletin (Vol. I), all
of which include information on the subject.
According to the Japanese, their "reverses" in and
around Wau, New Guinea, were caused by insufficient
rations, inexperience in jungle movements, and unfamiliarity
with the terrain. Blame for many of the
shortcomings in this and other unsuccessful South
Pacific campaigns was placed on junior officers and
Discussing the plans of United Nations forces, a
Japanese source points out that "everything hostile
forces do has a meaning; no matter how small the
details, each is a part of a plan. Therefore, it is important
that we observe such things at once. If we
fail, we will be taken in by the opposing forces."
"When we perceive these details," the Japanese
treatise continues, "we must next decide on plans to
counter the opposition, and take advantage of weaknesses.... If
you keep studying your opposition, no
matter how small and insignificant the information
may appear to be, you will improve your judgment
for use during critical moments."
Japanese notes on training stipulated that:
(1) Battle regulations be read until they were memorized by all personnel.
(2) Officers thoroughly instruct their men on enemy weapons,
uniforms, and features (they should at least be able to identify
an automatic rifle by its sound).
(3) The ability of troops to throw hand grenades be improved.
(4) Training be given in climbing and descending cliffs by
means of ropes (this applies particularly to heavy-weapons units).
(5) Further training be given in the transmission of orders. (It
is necessary to insure accuracy in this phase of warfare. If
circumstances permit, it is best to write out orders before they
b. Disposal of Booby Traps
The Japanese look for booby traps in areas where
United Nations forces expect the former to pass, or in
areas the Japs might pass over to avoid booby traps.
If a booby trap is discovered, the Japanese search
the area thereabouts for others. The first unit passing
through a booby-trapped area should remove the traps, according
to enemy instructions.
A Japanese report on jungle equipment stated that
leather shoes should be worn because rubber-soled shoes
caused soldiers to slip easily. The report included the
following additional points:
(1) Uniforms should be dark green.
(2) Each section should be furnished two automatic rifles
similar to those used by U.S. forces.
(3) Each company should have two guns of a type between a grenade thrower and a rifle.
(4) It is necessary to have field guns (100-mm howitzers, if
possible). Hostile field pieces have been very successful, and
we have had no really effective answer. If we had field guns
with us, the hostile artillery positions could be neutralized.
(5) Comparatively speaking, our grenade throwers are inferior
to those used by United Nations forces.
(6) There have been times when our hand grenades misfired
because they were damp.
d. Care of Wounded
The Japanese "very much regretted" that it was
necessary to leave the wounded behind in the Wau
operations. "In the future we will give further attention
to arrangements for rescuing the wounded. However, if
the wounded cannot be rescued, they must be
ready to commit suicide at the proper time—that is, after
all means to continue the fight have been exhausted.
"In case the wounded are retiring to the rear, always
let them carry their small arms and equipment. Their
ammunition should be left with comrades at the front. It
is regrettable that there have been numerous instances
of wounded men abandoning their weapons on
the battlefield. Also, there have been instances of men
leaving the front line without permission immediately
after suffering wounds. This is prohibited."
During movement in the jungle, Japanese combat
forces usually are preceded by a road-repair section, which
clears obstacles and takes other possible steps
to facilitate travel. In mountainous terrain, this section
hangs ropes, erects steps, and constructs guards to
prevent troops from slipping.
The force commander usually distributes radios at
intervals in the column during the march, to keep himself
informed about the situation.
Because the heavy-weapons unit moves more slowly
than other units in the column, a Japanese regimental
commander suggests that it travel independently in
a separate column. In the rugged terrain of the Wau
area, the rate of march of an enemy heavy-weapons
unit was only about 4 miles per day, alternating 20
minutes of marching with 20 minutes of rest.
The Japanese regimental commander recommends
that, during marches in the jungle, bivouacking be
done in march formation along the road. However, he
adds, the force in the column must shorten its distance
to the front. Seldom are there places where the force
may assemble together.
The force should go into bivouac 1 1/2 to 2 hours before
darkness and should leave about 1 hour after
dawn, according to the regimental commander.
To aid their movement at night, a Japanese unit on
Bougainville Island marked a trail with vines which
had been tipped with phosphorus.
b. Combat Methods
(1) Launching the Attack.—The following notes on
Japanese combat methods were paraphrased from enemy sources:
In the jungle, dawn and dusk are considered the best times
to launch an attack, especially if it is raining. Under such
conditions the hostile forces are under tents in trenches, and
therefore it is easier for us to approach undetected.
Gaps between hostile positions are comparatively wide (75 to
100 yards), and in many cases they are poorly guarded—sometimes
not at all. Therefore getting into these positions is a simple matter.
It is bad tactics to concentrate on, or be diverted to, the
front of the hostile forces. It is usually best to employ a small
part of your force to make a frontal attack and use your main
forces to attack the rear and flanks of the opposition.
When a frontal attack is employed, it is necessary to make
thorough preparations. The plan of attack must call for the
most effective use of the various heavy weapons and for full
use of artillery. Because the terrain is generally wooded and
affords a limited field of fire, it is easy to conceal our movements
while assault preparations are being made. The depth of
hostile defense positions does not exceed 650 yards during the
first stages of combat. The curtain of fire at the front of these
positions is heavy, but from there to the rear it thins out.
Hence it is advisable to make a bold, decisive breakthrough at
After launching a frontal attack in a wooded area, it may be
advantageous to shift the main force to the rear and flanks of the
opposition. This method is particularly good against forces
defending a defile along the beaches.
If hostile forces unexpectedly fire on you in the jungles or on
grassy plains, do not become excited and return the fire. You
must guard particularly against making noises. If you are in
position under a unified command, the commanding officer will
be prepared to take offensive action against the opposing forces.
You must be continuously on the lookout for hostile observers
and snipers, and pick them off with carefully aimed shots. Where
their presence is suspected, spray the trees with machine-gun fire.
In New Guinea we used our light machine guns too liberally, and
suffered a relatively large number of casualties among the
machine gunners. Riflemen should be used to search out the
hostile positions, while the light machine guns should be
reserved for definite targets.
If our positions are discovered by hostile mortar fire, we
must change positions immediately, first retreating
about 100 yards.
The power of hostile forces can be effectively reduced by cutting
off their supplies—this breaks their fighting spirit. Therefore,
at every opportunity, launch surprise attacks in the rear
for this purpose.
Our soldiers must rely on their bayonets. U.S. troops depend
too much on their fire power and lack the will to fight, both
physically and spiritually. Therefore, have confidence in your
bayonet, and lunge at your foe. In bayonet drill, practice the
straight lunge, with your right foot well forward, so that the
bayonet will penetrate all the way to its guard.
(2) Enemy "Rules" for the Attack.—The following
Japanese combat "rules" were extracted from an enemy manual:
(a) Take advantage of semidarkness as well as of bad weather.
(b) If you encounter hostile forces unexpectedly, take the
initiative and fire without hesitation.
(c) If you are in an exposed area of the jungle, find something
with which to conceal yourself, instead of dashing around.
(d) Hold out until the end, because your foe will not rush
you. However, be careful of his fire power and hand grenades.
(e) Always use the assistance of others instead of fighting
alone. Make contact with your own troops in every possible way.
(3) Tactics Observed in Burma.—Just before certain
attacks in the Burma theater, the Japanese reserve
forces screamed and yelled. Their forward
troops soon joined in the noise-making. Observers
said such tactics were obviously designed to break the
morale of the defending forces, to bolster Japanese
morale, or to make it appear that the attacking troops
were numerically stronger than they actually were.
The Japanese apparently made definite plans to
concentrate their attacks in particular sectors, because
they continued to press the attacks regardless of
casualties or the strength of the opposing forces.
Meanwhile, the enemy sent small parties to determine
the location of the opposing flanks, with the possible
intention of causing United Nations commanders to
pull troops from front sectors to strengthen their
flanks. Regardless of these maneuvers, the Japanese
always concentrated on the attack sector previously
selected, and tried to overwhelm the opposition by
weight of numbers.
Besides probing fire, the Japanese have used two
other methods to tempt United Nations forces to fire
and give away their positions:
(a) Japanese soldiers, each equipped with a length
of rope, tied the latter to bushes and then moved to a
place of safety. Then they worked the rope in an
effort to make opposing forces believe that enemy
troops were moving among the bushes.
(b) Enemy soldiers employed a simple mechanical
device to represent the clicking of rifle bolts. The
device in each case was attached to a bush and connected
by a rope to a soldier hidden in a place of
safety. By manipulating the rope, he made the device
sound like the operation of a rifle bolt.
c. Reaction to Ambush
Observers state that, as a general rule, the Japanese
in the Burma theater have reacted in the following
manner to ambushes:
Leading enemy elements got off the road or trail
and sought to outflank the opposing forces. Then the
Japanese opened up immediately with mortars (they
are seldom without them) and attacked, astride the
road or trail, the area in which the ambush was laid.
When ambushed, some Japanese soldiers have been
known to fall and feign death.
d. Special Assault Units
In the South Pacific theaters of operation, the
Japanese have employed several types of special assault
units. In most cases they were not specially
trained troops but combined units—or parts of units—selected
to accomplish special missions, such as raiding
lines of communication or artillery positions.1 Some
of these specially organized units were instructed
to withdraw after accomplishing their mission,
while others were designated as "suicide units."
The organization and mission of two of the "suicide
units" in New Guinea operations were described in
Japanese reports, which are paraphrased below.
One assault unit, commanded by a lieutenant, consisted
of an infantry company and a detachment of
engineers. This unit was to "advance within close
range of the enemy's main position and attack." The
engineers, acting as a demolition detail, were to carry
Bangalore torpedoes "to destroy all obstacles and mop
up within the positions." Two "suicide raiding units" of
six men each were assigned to "penetrate No. 2 and No. 3 enemy
positions," and to assist the main assault
unit by "throwing the enemy's rear into confusion."
To assist in the operations, a second company was to
act as a decoy, while another company was to advance
closely behind the assault unit and "leapfrog" the
latter at the appropriate time.
The assault unit was organized as follows:
Headquarters, 4 men; Assault Detail, 15 men; Obstacle
Detail (1 platoon engrs.) ; Artillery-demolition
Detail, 6 men; Raiding Detail, 7 men; Supporting
Detail, 22 men; Reserve Detail, 32 men; Mopping-up
Detail, 33 men.
The Assault Detail consisted of four "Grenade
Groups," while the Supporting Detail had one light
machine-gun squad and one grenade-thrower squad. The
Reserve Detail included a rifle squad, a light
machine-gun squad, and a grenade-thrower squad.
The second assault unit described by the Japanese,
also led by a lieutenant, consisted of infantry and
engineer troops. Its mission was to attack a U.S.
coastal base from the sea. The enemy order covering
the operation included the following:
The strength of the unit will be divided into two
sections, combining infantry and engineer troops. There
must be close coordination between the attacks by the
infantry and the demolitions carried out by the engineer troops.
Equipment will be as light as possible. In addition to the necessary
ammunition, carry as many grenades as you can.
The landing beach will be indicated under a separate order. Your
objectives should be ammunition dumps, artillery positions, tanks, enemy
headquarters, moored boats, barracks, and so forth.
The boat unit will return as soon as the assault unit has landed.
The attack must be completed before daybreak.
After the attack, the commander of the assault unit will use
his own initiative as to whether he will concentrate his forces
within the position penetrated or concentrate outside the
position. However, he must be situated so that he can
support the main regimental attack.2
a. Organization of Positions
(1) Real.—Figure 4 is an exact tracing of a Japanese
drawing to illustrate the organization of a defensive
squad position. This set-up apparently was designed
after the "Wau operations" in New Guinea. According
to the drawing, emplacements for three to
five men are constructed at each point of the triangle (a Japanese
rifle squad is approximately the same size
as ours). The distance between each group depends on
the density of the jungle; however, groups must be
within sight of each other. Each group of men is well
equipped with hand grenades. The squad leader stays
in whichever group is most convenient. "It is best," declares
a Japanese source, "to connect communication
trenches between the two groups. If one of the
groups is attacked by hostile forces, the other groups
will attack the rear flanks of these forces. If the latter
penetrate to the center of the position, you will use
|(A) 3 to 5 men
with hand grenades|
(B) Distance between positions
on density of jungle
|Figure 4. Japanese Squad
(2) Dummy.—A Japanese source states that "we
have used various devices for constructing dummy
positions and personnel, and also for firing from unexpected
directions. Everyone should keep planning these day by day."
The enemy apparently is particularly interested in
luring U.S. artillery to fire on dummy targets. In
this connection, a paraphrased Japanese treatise reads:
Experiments conducted during the fighting at Munda proved
that suitably prepared dummy positions and dummy guns were
extremely effective in drawing hostile artillery and bombing attacks.
In accordance with these results, always try to build
dummy gun positions some distance away from our real positions.
Another method of drawing hostile artillery fire is to send
out patrols to light fires. The smoke from these will certainly
tend to bring down artillery fire on the area. This patrol must
be led by an officer because the site must be selected with great
care to prevent the hostile fire from reaching real positions.
[NOTE.—Since the Japanese repeatedly give strict warnings
against the lighting of fires, smoke columns should be viewed
A U.S. observer in a Southwest Pacific area described
a dummy gun position and several dummy
antiaircraft positions. The dummy gun was a coconut-palm
log painted gray, with one end hollowed out to
represent the muzzle. From a distance of 100 yards
it appeared real.
Dummy soldiers were found at the antiaircraft positions. They
consisted of tree limbs nailed together,
with coconuts used as heads and Japanese uniforms
used for clothing. The dummy antiaircraft guns consisted
of tree trunks or limbs tied together. A large
limb represented the receiver and a smaller one represented
the barrel. It is doubtful if these positions
would have deceived ground troops at a distance of
200 yards or less.
b. Plans to Counter U.S. Tactics
(1) Action Against Patrols.—In New Guinea, Japanese
troops were ordered not to answer the searching-fire
of hostile patrols. "One way to annul their intention (they
seek to locate your positions) is to have snipers
shoot the patrol," the order read. "Another
method is to hide quietly, remain motionless until the
patrol passes, and then knock the hostile troops out
with one blow."
(2) Action against Ground Attacks.—The following
information on Japanese tactics designed to counter
U.S. offensive power is paraphrased from enemy sources:
Hostile attacks in a wooded area will usually begin with
automatic rifle fire; the effective range is about 50 yards.
Therefore, we can neutralize this fire by clearing a 50-yard area
in front of our positions.
In wooded areas there have been instances of hostile forces
attacking at close quarters. Troops must not neglect to guard
all directions at all times; we cannot always depend on patrols.
There have been instances in which patrols were lost in wooded
areas and could not report at the proper time. Do not send
them out too far; limit their area and give them a specific
mission, so that they can be recalled at a suitable time.
While standing guard, do not move your head quickly, otherwise
you will often be detected. Make a hole in a big leaf and
stand behind it, or construct a cover.
When cool firing is difficult due to heavy hostile automatic-weapons
fire, there are many occasions when hand grenades will
prove effective in carrying on the fight.
When hostile forces begin to retreat, the men on guard will
increase their fire power and will launch a counterattack to destroy
the opposition. However, take precautions to see that the
men do not lose their way back.
Guards will entice small hostile forces to approach as close
as possible and then destroy them. When somewhat larger
forces attack, you must commence firing outside of grenade-
throwing range (50 yards).
The hostile forces [U.S. troops] do not possess very effective
strength in the assault, but they will try to annihilate us by
relying on fire power alone; therefore we will be wiped out if
we try to defend ourselves while remaining in one place.
When hostile forces attack, we must act quickly in a minimum
of time and confuse them by destroying the attacking unit. In
using this method, we must preserve our strength instead
of displaying it all on the front line. When we attack, the rear
flank of the opposition will be the objective.
The hostile forces are skilled in approaching by crawling, and
they often get within 15 yards of our troops without being detected. They
open surprise fire with very rapid-firing automatic
weapons and deal destructive blows. However, they do
not charge; their grenade throwers approach and toss grenades
or shoot them with grenade rifles. If our positions are held
strongly, the opposing forces will retreat after a short time, or
they may send combat details around our flanks to attack with
grenades and automatic weapons.
In taking countermeasures against such hostile attacks, we
must scatter the opposing forces and then carry out a strong
assault at one point. It is usually advantageous to attack the
hostile flanks with two or three squads. Draw the opposition
close by remaining under complete cover. Then, by surprise and
accurate fire, kill the light machine-gun operator. However
small your force may be, prepare to fight on all sides, and try
to envelop any hostile envelopment by concerted action.
Clear away the underbrush for a distance of 15 yards from
your positions; remove no more underbrush than necessary so
that the clearing will not be noticeable.
Hostile forces seldom, if ever, attack at night. When they
are aware that their positions are known to us, they frequently
fire tracer bullets and rifle grenades—this is searching fire intended
to make us retaliate and reveal our positions.
At times hostile patrols penetrate to our rear—this generally
occurs during the first half of the night.
(3) Action against Parachutists.—The following information
from Japanese sources was included in an
enemy order governing the defense of an airfield
against U.S. parachutists:
Hostile parachute units, when attacking airfields while the
wind is blowing, will fly in down-wind* bail out against the
wind, and descend with the current. The parachutists, as a
general rule, will descend after hostile forces have strafed or
bombed our defenses.
In defense against such parachutist attacks, site machine-gun
and rifle positions around and near the airfield so that these
weapons can be fired up and against the wind.
Keeping in mind the rate of descent (16.4 feet per second)
and the wind current, sights will be aligned at a point below
and down-wind to the parachutists.
The following table gives some examples of how to sight your
rifle or machine gun:
|1,640 yds|| ||8 leads down 3 leads right. |
|1,312 yds||6 leads down 2 leads right. |
|1,094 yds||3 leads down 2 leads right. |
|656 yds||3 leads down 1 lead right. |
|328 yds||aim at feet. |
1 "How Japanese Raiders Demolish Artillery," a section
based on enemy sources, appeared in Intelligence
Bulletin, Vol. II, No. 4, pp. 13-16.
2 Although the two attacks referred to above took place as planned, both
were almost complete failures.