The following information on Japanese methods of
overcoming obstacles was extracted from an enemy
publication dealing with field fortifications. A study
of these methods should prove helpful to U.S. military
personnel concerned with the defense of obstacles
against Japanese attacks. However, these methods
should not necessarily be construed as complete and
up-to-date enemy tactical doctrine on the subject.
In connection with this section, reference should be
made to "Notes on How Japanese Attack Pillboxes" (Intelligence
Bulletin, Vol. I, No. 12, pp. 54-60).
2. WIRE OBSTACLES
In determining where a breach will be made in a hostile wire
obstacle, select a section which will facilitate the operations,
provided the selection will fit in with the over-all tactical plan.
Generally speaking, select portions of wire obstacles which have
been damaged by shells or bombs, or are easily approached.
The organization and equipment of demolition parties vary
according to the particular situation. Personnel include the
party commander, operators, and relief men, who constitute a
reserve and act as sentinels. The equipment includes wire
cutters, Bangalore torpedoes, hand grenades, smoke pots,
and, depending on the situation, portable shields,
sandbags, and so forth.
a. Operating with Secrecy
To make a breach in a hostile [U.S.] wire obstacle secretly, the
demolition party must be thoroughly rehearsed beforehand
in all details.
In cutting wires, first investigate the presence or absence of
thin wire, the condition of intersecting wires, the presence or
absence of alarm installations, and so forth. Then open wide
the handles of the wire cutter, raise the catch claw (a stick in a
piece of bamboo), and, after slowly inserting the wire cutter
all the way at a right angle about 1 foot from a post, press the
handles with both hands and make a notch in the wire. Grasp
the notched wire with both hands, one on either side of the
notch, and hold the long strand fast; without making any noise,
bend and break the short strand. Bend the end of the short
strand close to the post in the direction of the opposing forces,
and immediately thereafter stick the end of the long strand into
the ground as far as possible from its point of attachment, or
tie it to some natural object.
When two men operate jointly, one man (A) holds both sides at
the cutting point, and the other (B) makes the notch. (A) breaks
the wire, following the principles outlined above, and (A) takes
care of the long strand and (B) the short strand.
While cutting wire, the operator must rest one elbow against
his body, on the ground, or on a post. In cutting the lower
strands, he will kneel or lie down; he will assume any
convenient posture while cutting the higher strands.
In placing Bangalore torpedoes under wire obstacles, two men
are employed. After the rear man has removed the safety catch
and screwed in the igniter, and the front man has ascertained
the spot where the torpedo will be placed, the two operators push
the weapon on the ground to its final position. Sometimes a torpedo
is placed in position by use of pulleys.
In igniting Bangalore torpedoes, the rear operator pulls the
string with a sharp jerk and, within the delay time, withdraws
10 or more yards to the rear and lies down. To avoid any danger,
all personnel take full advantage of terrain or natural
objects which afford protection.
In case a Bangalore torpedo fails to explode, the demolition
party should have a torpedo in reserve, or be prepared to use
Should the demolition party be illuminated by hostile searchlights
or receive fire, it must try to maintain as much secrecy
as possible and continue its work with perseverance and fortitude.
When the demolition is completed, the party commander reports
by means of previously arranged signals and fixes the
necessary markers. He also acts as an observer and watches at
b. Operating under Fire
To succeed in cutting a breach in a wire obstacle while under
fire, the demolition party must work with speed, decisiveness, and
daring. It must take advantage of all opportunities to
neutralize or impair hostile fire by means of our own fire power
In cutting the wire, open wide the handles of the wire cutter,
put yourself in a position to support the left (right) elbow,
and cut so as to push the wire with the right (left) hand; cut
straight through at right angles. The point of cutting should
be as near a post as possible.
In placing Bangalore torpedoes under wire obstacles, one man
forward generally keeps the head end of the torpedo at the
selected post, and two rear men insert the weapon with one
shove. Sometimes, depending on the situation, it is advisable to
place the torpedo on top of the wire and ignite it.
In disposing of steel wire nets, whether secretly or while
under fire, the demolition party should either cover them, clear
them away, or destroy them with Bangalore torpedoes. If
necessary, have troops lie temporarily on top of the wire net and
press it down.
In using the implements to overcome abatis secretly, open a
passage, if possible, by cutting off the branches close to the
surface of the ground and slowly clearing them away to an
adequate extent, with all personnel cooperating.
In making a breach in abatis while under fire, first cut any
wires, then cut the branches and remove them to one side.
Sometimes it may be better to dig the abatis from their foundations
and clear the branches away. Those not firmly secured
can often be cleared away by attaching a net to them and
To destroy abatis by means of Bangalore torpedoes, rest the
pipe on the forked part of the branches on the front edge.
Remember that simple abatis are often combined with hand
grenades, and land mines, and so forth. Demolition or removal
in such cases will be carried out after first disarming the weapons.
4. ANTITANK OBSTACLES
To enable passage of tanks over an antitank ditch, blast down
the sides of the ditch with explosives, or tear down the slopes
with implements, or fill the ditch with sandbags and other suitable
material, or set up a gabion or framework.1
To destroy iron-rail barriers and abatis, explode grouped
demolition charges or Bangalore torpedoes at the base of the
obstacles, or clear them away by use of suitable implements.
To enable tanks to cross an antitank pit, lay logs over the
top at right angles to the direction the tanks will travel; or
place gabions, and so forth inside the pit. In laying logs, be
sure that they are firmly placed to prevent slipping. The interval
between logs varies with the type of tank. For medium
tanks the interval should be not more than 1 1/2 yards; for light
armored cars it should be not more than 2 1/2 feet. In putting
a gabion inside the pit, it is necessary to consider the distance
it will sink by the weight of the tanks. If frames are used, all
parts should be connected by wires, or iron fasteners. It will
be advantageous to carry along several types of frames, prepared
so that we can place them simply and quickly, as desired.
1A gabion is a cylindrical basket woven with open
ends; it is filled with earth and generally used as a retaining
wall in constructing fieldworks. In modern warfare sandbags are
generally used in place of gabions.