The following notes on Japanese tactics were made after observation of fighting on Guadalcanal.
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The Japanese is a night fighter. He does not move or attack in the daylight, or even in
moonlight. He waits till a dark night, moves in close, and attempts, by infiltration, to
seep through a weak spot in the line. He then attempts to create confusion and thereby
allow other Japanese troops to enter the line. Presumably, in case of a breakthrough, he
would consolidate the next day, and prepare for another attack. In case of a rout, he would
undoubtedly continue the attack in the daytime.
One method of attack used was for an advanced detail to move in quietly, followed by a larger
detail making considerable noise. The noise of the large detail subsequently covered the cutting
of wire, brush, etc., by the advanced detail and allowed it to break through the lines. When our
troops heard the larger of the two details, they allowed them to approach to very close range
before opening fire. However, by this time the smaller detail was in rear of our force and
began to fire. Unless proper security measures are taken to give warning of this and similar
tricks, the effect of the fire from the rear is apt to be so demoralizing as to cause troops
Defense against Japanese attacks must principally be against infiltration. It is obviously
impossible for defense lines to be manned with a man every 2 feet, and even though it
were possible to have the men this close together, some Japanese would still seep through. A defense
should be organized with strongpoints properly adapted to terrain features. If possible they should
be organized for all-around defense, with barbed wire and land mines in front of
positions, and wire behind. Intervals between strongpoints must, of course, be covered with
strong automatic and mortar fire, and if the intervals are large enough, with artillery
fire. Reserve elements should be employed to wipe out the isolated enemy elements that
Several bands of barbed wire should be laid around a position, and for this use concertina
wire is preferable to the double apron, as it is much harder to cut. Troops expecting to
defend in jungle terrain should carry large amounts of concertina wire. It is suggested that
several tin cans or other noise-making devices be strung along this wire so as to betray the
general direction of attack.
The Japanese use very few commands in battle. Apparently the troops are thoroughly drilled in the
particular operation and continue through with it. Very pistols, somewhat similar to ours, are used
to show the direction of advance. In the attacks against us, a red Very pistol light was
used, and served the purpose of converging all units in that particular vicinity toward a
certain direction. This, when discovered, enabled us to move reserves to the threatened
area. A green Very light meant a withdrawal. If Japanese signal lights can be captured and
used, it would undoubtedly be possible to create confusion in their lines by shooting off
flares at the wrong time. Our own Very pistol flare differed enough from the Japanese light
so that it did not fool them.
Quite a number of the Japanese, probably officers, speak perfect English and use this to trick
our troops. On one occasion a Japanese was heard to call out, "Hold your fire, we are American
troops. I am bringing in a patrol." Upon several occasions our telephone wires were tapped, and
attempts made to get the operator to divulge information. In using the telephone, some type
of authenticator must be used, and even then no information of value should be transmitted
over the phone. The same applies to radio transmission.
The Japanese are not good shots. Over a hundred yards "they can't hit the well-known bull
with a bass fiddle." They have plenty of machine guns, both light and heavy, but are unable
to use them to the best advantage. They almost always fire in one direction, and very seldom
traverse. Their clips hold 30 rounds, and the gunner generally fires the entire clip without
The Japanese we encountered were long on guts and short on judgment. They charged time and again
against machine guns and 37-mm guns loaded with canister. They seemed unable to
change a plan once decided upon and attempted to carry it out even though it was apparently
impossible. This is no doubt due, to some extent, to the impossibility of getting the changes
around in a night battle. If beaten, and he must be badly beaten before he is stopped, he
withdraws to some predetermined bivouac area to "lick his wounds," reorganize, and prepare a
new plan. Aggressive patrolling should be conducted the day following an attack in order to
drive his patrols away from our positions. Strafing and personnel bombing should be used as
much as possible, as well as artillery concentrations.
Grenades are used extensively by the enemy. The Japanese grenade can be used either as a rifle or
as a hand grenade. Strictly speaking, it is not used as a rifle grenade but is fired
from a grenade thrower.
The training of troops likely to fight the Japanese should be at least three-quarters at
night -- night marches, night attacks, organizing defense at night, etc. Each individual must be
trained so that no matter what the situation may be, he will not become panic-stricken, but
continue to fight. There will be times when bodies of troops will become separated, but they
must continue their effort and not try to withdraw. Each individual must understand every
detail concerning the operations.
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A high-ranking American staff officer who observed operations in New Guinea submits the following
brief comments about what he saw of Japanese tactics and his opinions as to the measures designed
to cope with such tactics.
"The Japanese have covered themselves defensively by a multitude of extremely well-constructed and
camouflaged bunkers (or combination coconut tree trunks and earth pillboxes). Progress in advance
can only be made by killing and/or 'digging out' the Japanese occupying each bunker--a slow, tedious and
difficult process.... The operations have demonstrated one thing conclusively, and that is the
need for more detailed, extended, and thorough training of the individual soldier and the
squad, section, and platoon leaders. Scouting and patrolling, reconnaissance, and all phases of
small unit leadership should be featured.... The individual should be trained in finding his way
through thickly wooded and swampy areas and should be taught that such areas are an advantage
to the offense instead of something to be looked on with concern and hesitation. The fear of swampy
areas should be overcome by wading through them in training. Night field training should be the
rule and daylight field operations the exception...."