Considerable information about Japanese small-unit tactics has
been printed in previous issues of the Intelligence Bulletin (for
example, see Vol. II, No. 5, pp. 64-72, "Small-unit
Tactics Used by Japanese at Night"). Some aspects of this subject
not previously covered in detail are included in this section. These
new details are based on only one Japanese source; this
source, however, is believed to be reliable.
On Bougainville Island, the Japanese usually employed
two types of patrols: the reconnaissance patrol,
which reconnoiters terrain, hostile positions, roads, and
so on; and the so-called microphone patrol, which usually
destroys communication nets as well as microphone
installations. In each case, the strength of the patrol
is approximately one squad (10 men), but it may
vary according to the situation, mission, and the time
If time permits, long-range officer patrols are sent
out prior to an attack. Noncom patrols usually are
sent out on short and less important missions.
During the last few hours preceding attacks, the
microphone patrols, generally led by noncoms, are sent
Patrols generally study aerial photographs before
going out, and one of the main duties of patrols is to
confirm information indicated on these photographs.
All patrols are equipped for combat, but are instructed
to resist hostile forces only when necessary. The
equipment includes a light machine gun.
Just prior to an attack, most patrols stay out one
day, or less, but they carry more than one day's rations.
Patrols generally march in a staggered formation,
which consists of two single files on either side of a
trail or road. The interval between men in each file is
about 5 yards. The patrol leader and the light machine-
gun operator march at the head. In a withdrawal,
these two men remain in the rear until the other personnel
clear the danger area.
An overnight patrol generally does not bivouac, but
halts for extended periods of rest. The men usually
do not sleep, and all remain on watch.
When patrols are out for several nights, they maintain
sentries on watch within the bivouac area. Reliefs
are made about every 2 hours.
3. APPROACH MARCH
When a company is marching as a unit, normally a
platoon is sent about 30 to 40 yards to the front as an
advance guard. This is followed by a platoon, the
command section, and another platoon, at intervals of
approximately 20 yards. About a squad is used for a
rear guard. The flanks usually are secured by two
men, each about 50 yards to both flanks, but when contact
with hostile forces is imminent, a squad is provided
on each flank. When a battalion is marching as
a unit, about a company of advance and rear guards
is provided, and the interval between companies is
approximately 50 yards.
The formation used in a night march is exactly
the same, but, depending upon the situation and the
terrain, the interval between both individuals and units
is kept at a minimum. In all cases contact is maintained
by connecting files and runners, who are dispatched
from each unit to the unit immediately to its
rear. During night marches, luminous vines—which
can be found in most jungle areas of the Southwest
Pacific—are used for individual markings and also as
direction guides. These are fastened to the back of each
man's pack or may be wrapped around trees to designate
the route of advance.
The machine-gun company marches in the main body
with the battalion headquarters so that the company
can be dispatched immediately to rifle units or sectors
where it may be needed.
During a recent operation (Torokina, Bougainville Island), the
Japanese normally marched 5 to 7 miles in the daytime, but
this is considered to be slow. When pressed for time, they
have covered 12 to 13 miles. During these marches there is
no particular rate of march and rest is taken as needed. The
Japanese consider that it is practically impossible to march
at night in the jungle, but if routes are known and
planned, 5 to 6 miles can be covered under cover of darkness.
During a halt in a daytime advance, both the rear
and the advance guards extend about 15 yards beyond
their normal march intervals (45-50 yds.). Each unit
observes to its immediate flanks. In special cases sentries
may be dispatched to the flanks. The same measures
are adopted for night security, but troops are told
to close up so that no one is left behind. Troops are
ordered to be very quiet.
4. ATTACK TACTICS
a. During the Day
Normally the Japanese move into an assembly area
before launching an attack. From this halt, units advance
to an area approximately 2 1/2 to 3 miles from
the opposing forces and make final preparations. At
this point the Japanese leave behind all surplus equipment,
and then advance to a line of departure, which
is generally located about 500 yards from the hostile
positions. At this point deployment is made, and the
attack is launched. The tactics employed are much the
same as those used in the night attack described in
paragraph 4b, except that a normal platoon front is
about 50 to 60 yards.
The Japanese heavy weapons are emplaced so that
they can fire against hostile heavy weapons and at the
same time assist the advancing troops. When a platoon
is attacking a position, the attached heavy machine gun
normally is located near the center of the platoon. The
heavy weapons are controlled by the company commander.
He designates the objective and the squad
leader in charge of the weapon decides as to its final
All communications are maintained by runners. In
case the heavy weapons are not under the control of
the commanding officer of the attacking unit, the orders
have to be issued by higher headquarters as to their
emplacement and duties.
b. During the Night
No definite amount of time is allotted for a night
attack. The time depends upon such factors as the
nature of the terrain, the size of the unit, and so on. However, after
arrival at the line of departure, there
usually is a 2-hour interval before the attack is
launched. The Japanese usually depart from the assembly
area at dusk, and favor using dawn for an
When a platoon is attacking a position at night, the
normal formation used is as follows:
The rifle squads are deployed on one line and within
contact of each other. If a heavy machine gun is attached,
this squad will follow the center squad on line
and keep within visual and voice contact. When faced
with a wire entanglement, one squad breaches the wire,
and immediately passes through and deploys to the left.
A second squad then passes through the same breach
and deploys to the right. The remaining squad, with
the heavy machine gun attached, moves up into a position
between the first two squads. The normal front
of a deployed platoon is 40 yards. In night operations
the surprise element is considered essential.
Contact between a squad leader and the platoon
leader is maintained by a runner and from a squad
leader to his men by voice and signals. Direction is
maintained by selecting intermediate objectives as the
advance progresses, or, if time permits, by using vines
or markers as guides. The platoon leader supervises
the maintenance of direction and controls the advance.
(1) Infiltration.—No set system of infiltration is
followed by the Japanese. Usually a squad at a time
is given the mission of infiltrating through the hostile
lines. The wire is breached and individuals move up
by crawling, or by short rushes. They take advantage
of moving during hostile firing and other noisy periods.
The Japanese depend solely upon grenades or bayonets
for protection, never returning fire. When a suitable
route has been established, contact is maintained by a
runner who infiltrates back and forth through the lines.
(2) Mortar Company.—For the Torokina operation,
the former battalion-gun platoon was reorganized
into a mortar company equipped only with 90-mm mortars. The
mortars were under the control of the
battalion commander—it is unusual for them to be
attached to infantry companies. The mortar company
normally moves with battalion headquarters and is
sent to vital points by order of the battalion
commander, according to the situation.
In coordination with heavy machine guns, mortars
are often deployed in support of advancing infantry
units. Observers are dispatched to a high spot or place
where concealment is readily available. In cases where
observation is limited, forward observers are used. In
these cases, reports from observers to machine guns are
transmitted by voice down a connecting file of men
stationed at various intervals between the observer and
the gun position. Communications between the battalion
command post and guns are maintained only by
runners. This method is slow and inadequate.
(3) Special Assault Teams.—In breaching wire entanglements,
specially trained assault teams are used
by the Japanese. An ordinary wire team, consisting
of six men and a leader, normally is employed for
breaching wire entanglements. Two men are designated
for cutting the wire, one man armed with a rifle
is stationed to protect the cutters, and two men are
held in reserve. However, in the Torokina operation,
only two- or three-man teams were used.
Each platoon has three wire cutters, one per squad.
Bangalore torpedo and demolition teams come from
within each infantry company. The commanding officer
controls this party, and, according to the mission assigned,
dispatches the type and size of team required
to accomplish the mission.
Special assault squads are an integral part of the
"working party" found in each battalion. They are
composed of approximately 20 men commanded by a
sergeant major or a warrant officer. This party carries
one flame thrower. For the Torokina operations, each
company was organized with a "Special Assault Squad." This
squad, composed of 10 to 12 men, carried
three Bangalore torpedoes. One man carried and operated
aflame thrower, while the number of men required
to use a Bangalore torpedo varied with the length of
torpedo used. The number of covering riflemen varied
with the situation.
(4) Snipers.—The squad leader and platoon commander
select snipers from the riflemen of each squad.
The selections are made on the basis of intelligence as
well as marksmanship. The training of snipers is conducted
by each company or battalion, depending upon
the situation. First of all, they are given further training
in marksmanship, using both moving and stationary
targets. Correction of windage is also stressed
in this practice. They then receive training in estimating
the range with the naked eye. The snipers use the
regular Model 38 rifle, fitted with a telescopic sight and
a folding bipod. The primary target for snipers is the
apparent leaders of the units they may encounter. The
maximum effective range for sniping is considered to
be 300 yards.
(5) Communications.—All communication is by
runners who are dispatched from the lower units. During
combat, two messengers familiar with the terrain
and local dispositions are dispatched by the squad
leader to the platoon commander. Each platoon, in
turn, sends out its runners to the company command
post; Runners are normally sent out in pairs, but, depending
on the importance of the message, this number
may be increased. The senior man is put in charge and
actually carries the message; no particular formation is
used, and the men always travel together. However,
during the Torokina operation, a so-called liaison section
was organized within each platoon; this section
consisted of six men (including officers' orderlies)
which were used by the platoon leader as runners and
messengers. All runners are instructed to memorize,
if possible, the order they are transmitting. However,
long orders usually are written down.
Usually no telephones are used, even for communication
between company and battalion. However, if one
company is dispatched to a distant location for guard
duty, telephones may be used for company and battalion