Infantry Drills

FM 3-21.8 – Chapter 8 – Section VIII – Retrograde

Section VIII – Retrograde

8-175.  The retrograde is a type of defensive operation that involves organized movement away from the enemy. The enemy may force these operations, or a commander may execute them voluntarily. Retrograde operations are transitional and are not considered in isolation. There are three forms of retrograde: withdrawal; delay; and retirement. Platoons may participate in stay-behind missions as part of a withdrawal or delay.


8-176.  A withdrawal occurs when an element disengages from enemy contact to reposition itself for another mission. A platoon usually conducts a withdrawal as part of a larger force. As part of a company, a platoon may withdraw with the main element (under pressure) or may be used as the detachment left in contact (DLIC) in a withdrawal not under pressure. This information applies whether or not the platoon is under pressure from the enemy. Regardless of employment, the platoon leader conducts his withdrawal IAW his higher commander’s guidance. On receipt of the order to conduct a withdrawal, the platoon leader begins preparing his order based on his higher unit’s FRAGO. He identifies possible key terrain and routes based on the higher unit’s graphics and his map. He formulates and briefs his FRAGO to his squad leaders. When the withdrawal is executed, squad leaders ensure they are moving IAW the platoon leader’s plan by monitoring position locations.

Withdrawal Not Under Pressure

8-177.  In a withdrawal not under pressure, platoons may serve as or as part of the DLIC. A DLIC is used to deceive the enemy into thinking that the entire force is still in position (Figure 8-27). As the DLIC, the platoon—

– Repositions squads and weapons to cover the company’s withdrawal.

– Repositions a squad in each of the other platoon positions to cover the most dangerous avenue of approach into the position.

– Continues the normal operating patterns of the company and simulates company radio traffic.

– Covers the company withdrawal with planned direct and indirect fires if the company is attacked during withdrawal.

– Withdraws by echelon once the company is at its next position.


Figure 8-27. Withdrawal not under pressure.

Withdrawal Under Pressure

8-178.  If the platoon cannot prepare and position the security force, it conducts a fighting withdrawal. The platoon disengages from the enemy by maneuvering to the rear. Soldiers and squads not in contact are withdrawn first to provide suppressive fire and to allow Soldiers and squads in contact to withdraw.


8-179.  Based on orders from the battalion commander, the company commander determines how long to retain defensive positions. The company may be required to remain and fight for a certain amount of time, or it may be required to disengage and displace to subsequent positions. A platoon, as part of a company, may disengage to defend from another battle position, prepare for a counterattack, delay, withdraw, or prepare for another mission.

8-180.  Fire and movement to the rear is the basic tactic for disengaging. All available fires are used to slow the enemy and allow platoons to move away. The company commander may move his platoons and mass fires to stop or slow the enemy advance before beginning the movement away from the enemy.

8-181.  Using bounding overwatch, a base of fire is formed to cover platoons or squads moving away from the enemy. One platoon or squad acts as the base of fire, delaying the enemy with fire or retaining terrain blocking his advance, while other platoons or squads disengage.

8-182.  Moving platoons or squads get to their next position and provide a base of fire to cover the rearward movement of forward platoons and squads.

8-183.  Fire and movement is repeated until contact with the enemy is broken, the platoons pass through a different base-of-fire force, or the platoons are in position to resume their defense (Figure 8-28).


Figure 8-28. Bounding overwatch to the rear.

8-184.  Tactics used by the platoon to disengage from the enemy differ according to the company commander’s plan for disengagement, how the platoon is deployed, and other factors. The following actions apply in all cases:

– Maximum use is made of the terrain to cover rearward movement. Squads back out of position and move, attempting to keep a terrain feature between them and the enemy.

– Rapid movement and effective base of fire enhance mobility and are key to a successful disengagement.

8-185.  Plans for disengagement may be part of any defensive plan. When squads are separated, there are three ways they can disengage: by teams; by thinning the lines when they must cover their own movement; or simultaneously when they are covered by another force.


8-186.  When the rifle platoon must cover their own movement, two squads stay in position as a base of fire (Figure 8-29). The third squad and weapons squad move to the rear (crew served weapons move based on the platoon leader’s assessment of when they could best move). The squads left in position must fire into the entire element’s sector to cover the movement of the other squad(s). Sectors of fire are adjusted for better coverage of the element’s sector. The moving squad may displace by fire teams or as squads because there are two squads covering their movement. The squads left in position sequentially disengage. Movement to the rear by alternating squads continues until contact is broken.


Figure 8-29. Disengagement by squads.

Thinning the Lines

8-187.  When disengaging by thinning the lines, selected Soldiers from each fire team (usually one Soldier from each fighting position) disengage and move to the rear (Figure 8-30). The Soldiers still in position become the base of fire to cover the movement.

Figure 8-30. Disengagement by thinning the lines.


8-188.  Squads disengage simultaneously when they are covered by another force. Simultaneous disengagement is favored when rapid movement is critical; when the disengaging element is adequately covered by overwatching fires; when the enemy has not closed on the rifle squad or cannot fire effectively at it; and when there are obstacles to delay the enemy. Simultaneous disengagement is used when rifle squads are able to move before the enemy can close on their position. Other platoons of the company or battalion cover the disengagement with supporting fires.


8-189.  In a delay, the enemy slows its forward momentum when the platoon forces him to repeatedly deploy for the attack. After causing the enemy to deploy, the delaying force withdraws to new positions, trading space for time. A delay is typically done to buy time for friendly forces to regain the offensive. It is also done to buy time so friendly forces can establish an effective defense, or to determine enemy intentions. Inflicting casualties on the enemy is normally secondary to slowing the enemy approach. As part of a company or larger operation, the platoon can expect to be tasked as a reserve, security force, or part of the main body. The squads or sections and platoons disengage from the enemy as described in a withdrawal under pressure (see paragraph 8-176) and move directly to their next position and defend again. The squads and platoons slow the advance of the enemy by causing casualties and equipment losses by employing—

– Ambushes.

– Snipers.

– Obstacles.

– Minefields (including phony minefields).

– Artillery and mortar fire.

8-190.  A common control measure used in these missions is the delay line, which is a phase line the enemy is not allowed to cross until a specified date and time. Infantry must carefully consider the mobility difference between themselves and the attacking force, maximizing the use of both terrain and counter-mobility obstacles. A delay operation terminates when the delaying force conducts a rearward passage of lines through a defending force, the delaying force reaches defensible terrain and transitions to the defense, the advancing enemy force reaches a culminating point and can no longer continue to advance, or the delaying force goes on the offensive.


8-191.  Stay-behind operations can be used as part of defensive or retrograde operations. In these operations, the commander leaves a unit in position to conduct a specified mission while the remainder of his forces withdraw or retire from an enemy. Stay-behind is inherently risky, and resupply and casualty evacuation are difficult. Conducting stay-behind operations places a premium on Infantry leadership and initiative, and ultimately terminates when the unit conducts a linkup with attacking friendly forces or reenters friendly lines.


8-192.  The two types of stay-behind operations are unplanned; and deliberate.


8-193.  An unplanned stay-behind operation is one in which a unit finds itself cut off from other friendly elements for an indefinite time. In this kind of operation the unit has no specific planning or targets, and must rely on its organic assets.


8-194.  A deliberate stay-behind operation is one in which a unit plans to operate in an enemy-controlled area as a separate yet cohesive element for a certain amount of time or until a specified event occurs. A deliberate stay-behind operation requires extensive planning. Squads, sections, and platoons conduct this type of operation as part of larger units.


8-195.  Troop-leading procedures (TLP) apply to stay-behind operations. Planners must pay strict attention to task organization, reconnaissance, and sustainment.

Task Organization

8-196.  A stay-behind unit includes only the Soldiers and equipment needed for the mission. It provides its own logistics support and security, and must be able to hide easily and move through restrictive terrain.


8-197.  Reconnaissance is most important in a stay-behind operation. Reporting tasks and information requirements can include suitable sites for patrol bases, hide positions, observation posts, caches, water sources, dismounted and mounted avenues of approach, kill zones, engagement areas, and covered and concealed approach routes. The unit may be required to collect intelligence on enemy forces around them.


8-198.  Because the stay-behind unit will not be in physical contact with its supporting unit, supplies of rations, ammunition, radio batteries, water, and medical supplies are cached. Provisions for casualty and EPW evacuation depend on company and battalion plans.


8-199.  Retirement is a form of retrograde in which a force not in contact with the enemy, moves away from the enemy. Retiring units organize to fight but do so only in self defense. Retirements are usually not as risky as delays or withdrawals. Retiring units normally road march away from the enemy. Infantry platoons participate in retirements as part of their company and higher headquarters.

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