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"Japanese Defense Notes" from Intelligence Bulletin, December 1943

[Intelligence Bulletin Cover]  
The following report on Japanese defensive tactics in the Pacific was originally printed in the December 1943 issue of the Intelligence Bulletin.

[DISCLAIMER: The following text is taken from the U.S. War Department Intelligence Bulletin publication. As with all wartime intelligence information, data may be incomplete or inaccurate. No attempt has been made to update or correct the text. Any views or opinions expressed do not necessarily represent those of the website.]



The following notes on Japanese defensive tactics were paraphrased from translations of various enemy treaties on this subject. Readers are cautioned to bear in mind that these notes deal with combat methods devised for use by the enemy, and that they must not be confused with our own defense tactics.


Japanese plans to defend a certain area in the South Pacific are outlined below. The area is not identified.

a. General

We will defend our present positions to the last man, breaking up hostile attacks by fire power and counterattacks. Our reconnaissance must be precise and systematic so that we may avoid being taken by surprise. Those units on guard in the outer areas will keep as much of their strength as possible in a mobile state of readiness.

b. Tactical Points

Front-line companies will make reconnaissances of the area extending 1 kilometer from the hostile positions, battalions will be responsible for the first 2 kilometers, and the regiment for over 2 kilometers.

You will use infiltration and raiding patrols to confuse the enemy's rear.

Upon discovery of a new enemy plan, you will display initiative to disrupt those plans.

Every unit, from the smallest sentry group to the largest company; must consider the probability of hostile artillery attacks, and therefore strive to construct several alternate positions, to the left, right, and rear, so that our defense will be as mobile as possible.

Construct strong aerial-defense trenches.

Companies occupying positions the farthest forward will be relieved in about two weeks by battalion- and regimental-reserve units.

c. Supplies

"Get one of the enemy every time you shoot" is to be a maxim of this fight. The defenders must shoot the big forms of the enemy [United Nations] as they approach. As many provisions and as much ammunition as possible must be stored in the front lines. However, these supplies should be widely dispersed as a protection against bombing.

d. Communication

It is preferable to lay telephone wires between every observation post and company. Because of air attacks, important connections must be doubled. Also, wires must not be laid in groups. Men must be posted to guard wires, or reserve wires must be prepared.

Communication between platoons or sections should be done by signals or by the speaking-tube system. In front of hostile forces, it is quite unnecessary to speak in a loud voice or to dispatch messengers.

Radio equipment and telephones must be installed in strong air-raid shelters.


a. Reconnaissance

It is necessary to determine the landing plans of the hostile forces at an early stage. Their movements must always be observed—especially the activity of boats, torpedo boats, and reconnaissance planes. Patrol of the adjacent sea area by boats must not be left up to the Navy. Every unit must plan various measures for coast patrol. It is necessary to practice various methods of quickly reporting the discovery of hostile forces.

b. Tactics

Both day and night maneuvers must be held in rehearsing tactics to use in defense against landing operations. It is necessary to develop various plans that the enemy [United Nations] may use, and to work out the proper measures to counter these plans.

When it is known that hostile forces will attempt a landing, every unit must concentrate as much of its strength as possible to annihilate the invaders on the beach. Even those who are sick and wounded must, if at all possible, bear arms and participate in the battle with grim determination.

It must be remembered that the hostile troops, upon landing, will not be familiar with the situation and will have no constructed positions. Furthermore, they will be confused, due to poor liaison and lack of control, and will therefore be in a very disadvantageous position. Under such conditions it is possible for even one of our smallest units to destroy a large number of the invaders by fierce and fast attacks.

On the other hand, if the invaders are given time to reorganize and dig in, it will be very difficult to annihilate them later.


The following observations are made in connection with the American and British attacks on the Italian island of Pantelleria:

(1) To counter the enemy's [United Nations] large-scale, overwhelming air attacks, it is essential to possess sufficient fighter planes and absolutely complete antiaircraft defenses and ground installations.

(2) To counter hostile landings, it is essential to possess strong mobile forces for counterattacks, in addition to the fixed defenses for combat at the water's edge.

(3) Isolated islands require an accumulation of sufficient water, rations, and matériel.

(4) Evacuation of the inhabitants from Pantelleria was begun only a short time before the surrender. Although both planes and ships were used for this purpose, only a few hundred were removed. It was a blunder not to have cleared out all the inhabitants before the decisive attack, regardless of their devotion to their soil.


An antiaircraft observation party should have field glasses, shutter field glasses, and simple communication equipment.

The party should take up positions where its members will have a wide view and where the sound of planes can be easily heard. These positions should be located so as to facilitate communication with the officer in charge and with the appropriate antiaircraft units.

Antiaircraft observers must know how to distinguish between hostile and friendly planes.

When any evidence of a hostile plane is detected, report to the officer in charge and to the antiaircraft units in the vicinity. If the identity of the plane cannot be determined, the procedure will be the same.

Report to the officer in charge when a friendly plane is detected coming in our direction.


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