Marines Field Guide

Marines Field Guide

Defensive Combat

The purpose of defensive action is to retain or control terrain, gain time, develop more favorable conditions for offensive action, or to economize forces to allow the concentration of forces elsewhere.


The mission of the infantry in the defense is, with the support of other arms, to stop the enemy by fire as he approaches the battle position, to repel his assault by close combat if he reaches the battle position, and to destroy him by counterattack if he enters the battle position.

Fundamentals of Defense

The following fundamentals of defense are applicable to all tactical levels (fire team, squad, platoon, company, etc.). Application of these fundamentals by all unit leaders increases the chances for a successful defense.

A. Preparation. Normally, the defender will arrive at the battlefield before the attacker. Upon his arrival at the position he is to defend, the squad leader must ascertain from the platoon commander how much time is available to prepare his defensive position. If time is available to prepare the position the squad leader must use it wisely; if not, he prepares a hasty defense.

B. Concentration. Forces must be concentrated to prepare for attacks at the most likely spots.

C. Flexibility. Flexibility is achieved through the continuous development of various courses of action to meet the enemy threat.

D. Maximum Use of Offensive Action. The squad will normally be tasked by the platoon commander to conduct various types of patrols to maintain contact with the enemy.

E. Proper Use of Terrain. Take maximum advantage of the military aspects of terrain — key terrain, observation, cover and concealment, obstacles, and avenues of approach.

F. Mutual Support. An isolated unit is easily destroyed by the enemy. Positions should be located so that when attacking one, the enemy comes under fire from at least one other.

G. Surprise. The squad leader must employ every means available to mislead the enemy as to the true locations of his positions, his strength, and the disposition of his organic weapons as well as any crew-served weapons located in his sector.

H. Knowledge of the Enemy. Since the defense reacts largely to what the attacker does, the squad leader should find out the capabilities of the enemy facing him. Having an idea as to what the enemy can do, what weapons he will employ, and what his strength is, will help the squad leader organize his defense to meet that threat.

The Fire Team in the Defense

The squad leader organizes the fire team in the defense by specifying a sector of fire and principal direction of fire for the automatic rifle. He points out on the ground the general location of fighting positions to be occupied.

As the enemy approaches the platoon battle position, he is subjected to an ever-increasing volume of fire from weapons in the battle position and from supporting arms.

Defensive Procedures

Troop Leading Procedures in the Defense

Upon receiving the platoon defense order, the squad leader follows the steps to make the best use of time, equipment, and personnel. Utilizing these steps and satisfactorily completing an estimate of the situation, he issues his squad defensive order. This follows the five-paragraph order format which includes:

• Information about the enemy, the location and identification of adjacent units, and the location of supporting weapons within the squad area.

• The mission of the squad.

• Inspect the fighting position for each fire team member, verifying each man's ability to cover the fire team sector of fire.

• Assigning each automatic rifleman a principal direction of fire covering a likely avenue of enemy approach.

• Supervising the preparation of fighting holes.

• Supervising the clearing of fields of fire.

• Providing security by assigning sentinels or observation posts.

• Coordinating all security measures with adjacent squads and the platoon commander.

• Inspecting fighting positions to ensure that camouflage and overhead cover are satisfactory.

• Supervising the preparation of supplementary fighting positions.

• Establishing a system of signals for fire control.

A. Signal to Commence Firing. Normally, a forward limit is established to designate the range at which the fire teams are to open fire. For rifles and automatic rifles, this may extend as far forward as their maximum effective range. A terrain feature should be selected to locate the forward limit. As the attacker passes this limit, he is brought under fire. This establishes a positive means of fire control to ensure that small arms fire does not commence prematurely or is withheld too long. The squad leader may desire the fire teams to hold their fire until the enemy gets closer than maximum effective small arms range, and then deliver a heavy volume of surprise fire. In this case, he will establish a signal for commencing fire.

A. Signal to Cease Final Protective Fires. Predetermined signals are used to cease final protective fires. When the enemy assault is repulsed, the signal to cease final protective fires is given.

Posting Security

Local security consists of measures taken to prevent surprise and to deny the enemy information concerning the plan of defense. All-round security and protection against surprise are achieved by:

• Posting a sentinel for surveillance.

• Enforcing noise and light discipline.

• Keeping movement within the squad fighting position to a minimum

Security Forces

A. The squad may serve as part of a security force. Security forces are assigned three types of missions— screen, guard, and cover.

1. A screen is a security element whose primary task is to observe and report information, avoiding decisive engagement with the enemy. A screen accomplishes the following tasks:

• Provides early warning of enemy approach.

• Gains and maintains enemy contact and reports enemy activity.

• Within capabilities, destroys or repels enemy reconnaissance units.

• Impedes and harasses the enemy with indirect fires.

• Guides reaction forces.

2. A guard protects the main force from attack, direct fire, and ground observation by fighting to gain time, while also observing and reporting information. A guard accomplishes the following tasks:

• Provides early warning and maneuver space to the front, flanks, and rear of the main force.

• Attacks, defends, or delays, within its capabilities, to protect the main force.

3. A covering force is a force which operates apart from the main force for the purpose of intercepting, engaging, delaying, and deceiving the enemy before he can attack the main force. A covering force accomplishes the following tasks:

• Gains contact with the enemy.

• Protects the main force from engagement.

• Denies the enemy information about the size, strength, composition, and objective of the main force.

• Destroys enemy reconnaissance and security forces.

• Develops the situation to determine enemy disposition, strengths, and weaknesses.

B. The location and composition of the security force is determined by the commander of the main force. He will organize the security force according to the mission he gives it —screen, guard, or cover.

C. Generally, the role of the rifle squad as part of a security force will be the same, regardless of the mission assigned to the security force. The squad will report enemy sightings, take the enemy under fire, and withdraw only on orders from the platoon commander or the commander of the security force.

D. Withdrawal routes will have been previously determined and reconnoitered. Upon withdrawal and passage through the forward friendly unit, the squad will return to its parent platoon (if the squad had been operating independent of the platoon), which is normally part of a reserve unit.

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