1. DEFENSIVE POSITIONS
In recent months the Japanese have increasingly
been emphasizing the necessity for constructing more,
and deeper, communication trenches to connect defensive
positions. Emphasis also has been placed on
constructing individual shelters strong enough to protect
personnel from bombs and artillery shells. "The
usual tactics of hostile forces," according to a Japanese
source, "are facilitated if our individual shelters and
slit trenches are constructed separately."
The same Japanese source states that "communication
trenches (deep enough for a person to traverse in
a crouched position) between shelters are absolutely
essential. Communications during an attack are extremely
important, and if communication trenches have
not been prepared, intercommunication is impossible."
A U.S. observer recently commented as follows on
Japanese defensive positions:
In this area the enemy uses many communication trenches.
These vary from the crawl type to those deep enough for a
man to walk upright. The depth apparently depends on the
time available for digging. The Jap here, as everywhere, is a
continuous digger, and, given time, he constructs very elaborate
The most interesting thing about some of these trenches are
the holes dug into the sides, big enough to permit a man to
crouch. In such a hole, dug into the side at the bottom of a
trench 5 feet deep, a man has complete protection from all
types of fire. Not only is this type of shelter provided in
trenches, but a large number of individual foxholes have offsets
dug at the bottom in the same manner. A few of these
had been enlarged enough to permit a soldier to lie down and
sleep—in a sort of slit trench 4 feet underground.
In the case of one underground shelter observed, the entrance
began at the bottom of a trench and extended straight
down for 10 feet. It was necessary for the Japs to use a ladder
to get in and out. At the bottom of this "well" [entrance], a
short tunnel led to an underground room, which was roughly
6 feet wide, 8 feet long, and 3 feet high. The ceiling, walls,
and floor were completely lined with split bamboo. As though
the 15 feet of earth were not sufficient cover, the room was
placed directly under a thick clump of big bamboo trees. This
particular system of trenches contained a number of these
deep shelters, all of which were lined with bamboo.
A Japanese training memorandum stipulated that
positions be organized in depth, but that the interval
between positions must be short enough to permit
measures against hostile infiltration. The memorandum
In constructing positions, it must be remembered that the
jungle does not afford permanent shelter; it may be cleared
away by bombing and shelling. Deployment must be carried
out laterally and in depth, and preparations must be made just
as if the ground had been cleared previously.
On terrain which slopes down toward the hostile forces, it
is best to place defensive positions between 20 and 30 yards
below the crest line—because shells generally will either go
over the crest or fall short on the slope.
As a rule, the ground in front of positions should be cleared
a distance of 50 yards to facilitate observation and firing... It
is essential to keep all positions fully camouflaged. And
maintenance of a dummy position close to the front of the
main position is a profitable way of observing hostile firing.
2. DEFENSE AGAINST ARTILLERY
In Burma the Japanese have made little use of
artillery firing for counterbattery purposes. In the
isolated cases where it has been used, the firing has
been inaccurate and not concentrated. It is believed
that this firing was only for harassing purposes.
As their primary counterbattery measure, the Japanese
have used infantry attacks on gun positions.1 The
following are examples of how these attacks were
a. Twenty to 30 Japanese infiltrated through British
infantry posts, and, from a small hill, attacked four
artillery sections at night, firing machine guns sighted
on fixed lines and firing grenade dischargers. The attack
ended with a bayonet charge, which was repulsed.
b. A battery of four guns was in a position where
one gun was slightly separated and not visible from
the other three sections. At night about 20 Japanese
attacked the one separated gun section with grenade
dischargers and a bayonet charge. The attackers were
armed with explosive charges with which to destroy
the piece. After neutralizing this single section, the
Japanese attacked the three remaining sections but
were driven off.
c. A Japanese soldier crept up through the jungle
at night and was in the process of attaching a sticky
grenade to a gun tube before he was discovered and
3. OFFENSIVE TACTICS
The following information about Japanese offensive
tactics was extracted from an enemy training memorandum:
The interval between hostile [British] positions are relatively
long—75 to 100 yards—and there are many places loosely
guarded, especially in the rear. Therefore, it is easy to
infiltrate into the hostile positions.
In making an infiltration attack, as many grenades as possible
should be carried. About 10 men are needed to attack
each position, but these should be deployed as much as possible.
If more than 10 men are deployed, it becomes difficult to maintain
silence, and the lack of freedom for movement leads to
At each of his centers of resistance, the enemy [British]
will be confused by a squad, or less, which will hurl grenades
from the flanks and rear; the position will then be penetrated
by an immediate assault with cold steel...
1In this connection, reference may be made
to Intelligence Bulletin, Vol. II, No. 4,
pp. 13-16, "How Japanese Raiders Demolish Artillery."