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Chapter 5
Army Offensive Operations


Nondivisional Elements
Army Roles in Army Group Offensive
Prerequisites for Success
Influence of Nature of Enemy Defense
Army Missions
Single Penetration
Attack Across a Broad Frontage on Multiple Axes
Meeting Engagement
Attack Against a Defending Enemy
Developing the Offensive

An army offensive operation is normally part of an army group offensive operation. However, an army operating on a separate operational axis is capable of independent operations. The army is the smallest OPFOR organization fully organized and equipped to conduct operational maneuver. It can strike throughout the entire tactical-operational depths of the enemy using a combination of operational maneuver and fires.

The forms of maneuver and types of offensive action at the army level are similar to those at the army group, only on a smaller scale. Since much of the content of Chapter 4 applies to the army level as well, this chapter does not repeat the elements common to both army groups and armies; it concentrates on nuances peculiar to the army.


In wartime, the composition and size of an army reflect its mission, the situation, and the area of operations. An army has a permanent staff structure and a flexible complement of divisional and nondivisional combat, combat support, and combat service support elements. Its structure provides adequate control and ground-based support for the divisions assigned to it during the army's participation in an army group operation. When the army's divisions actively engage in army group combat operations, army group assets supplement the army's combat support elements.


The OPFOR employs two basic types of army: the mechanized army (MA) and the tank army (TA). While both types have a combined arms structure, a TA has a predominance of tank divisions (TDs). The MA normally has a predominance of mechanized infantry divisions (MIDs) or perhaps a balanced structure of MIDs and TDs.


The OPFOR also employs two types of corps, which may operate in lieu of armies in most situations. Both corps have a combined arms structure. The primary difference between armies and corps is the smaller amount of supporting assets and units allocated to a corps.

The OPFOR might choose to employ corps in its more austere theaters; for missions requiring a more compact force, such as an operational maneuver group (OMG); or simply when armies are not available. A tank corps has a predominance of tank divisions or separate brigades. A mechanized corps has a predominance of mechanized infantry units or, perhaps, a balanced structure of MIDs and TDs or mechanized infantry brigades (MIBRs) and tank brigades (TBRs).


The MA has no permanent organization. A typical mechanized army has two to five divisions, with four being the most common. There are generally at least two MIDs and one TD. Similarly, a typical TA has two to five divisions, with four again being the most common. There are normally at least two TDs and no more than one MID. A corps may have one or two divisions and one or more separate brigades.1

Nondivisional Elements

In addition to this flexible number of divisions, the numbers and types of nondivisional elements in an army can also vary greatly. Typically, either type of army may have--

  • One or two separate MIBRs or TBRs.
  • One or two separate combat helicopter regiments.
  • An artillery brigade.
  • A multiple rocket launcher (MRL) regiment.
  • Two surface-to-surface missile (SSM) brigades.
  • A surface-to-air missile (SAM) brigade.
  • An antitank regiment (MA only).
  • Possibly a special-purpose forces (SPF) battalion.

(See FM 100-60 for more detail on army and corps organizations.)


Just as army group offensive operations provide the vital ground maneuver element in strategic operations within a theater, it is actually the armies that conduct the operational maneuver for the army group. Within the context of the army group's offensive operation, an army executes its mission in close cooperation with adjacent armies and other elements of the army group.


The aim of an army offensive is to destroy enemy military forces and to achieve operational missions in support of army group operations. Thus, army operations may involve some or all of the tasks in the following paragraphs.

Destruction of Enemy Forces

This is the primary aim of most army offensive operations. An army might complete the destruction of enemy forces begun by an initial precision weapons strike or other means. An army might also be tasked to destroy enemy forces unaided by nonorganic means.

Seizure of Vital Areas

An army may have to capture terrain features and/or political or economic centers to create favorable conditions for subsequent operations. If the depth of a particular army group operation is not great and the enemy has no strong reserves in that sector, an army operation may achieve the goals of the army group offensive, or even strategic political goals.

Consolidation on Achieved Objectives

Only when specifically ordered to by the army group does an army stop and consolidate on an objective. Generally, missions are more in term of lines to reach (and forces to destroy in doing so) than of sectors of terrain to hold. Common exceptions to this rule are--

  • Transition to the defense on an army group's final objective, or subsequent mission line.
  • Consolidation of a bridgehead or other favorable line when the army lacks the strength to continue the advance.
  • Transition to the defense when faced by a superior enemy force.
  • Going onto the defensive when the army group switches the focus of its efforts.

Army Roles in Army Group Offensive

Armies conduct offensive (or defensive) operations in support of army group missions. Therefore, an army's missions depend on its role in the army group commander's concept of operations. Its missions also depend on its place in the army group's operational formation; that is, whether it is acting in the first or second echelon or as an OMG. These same two factors also determine the army's composition; that is, the number of divisions and the degree of support allocated to it from army group. Usually, MAs conduct penetration operations, act on secondary sectors or in difficult terrain, or serve as second echelons. A TA usually operates on the main axis, acting in the first echelon against weak or partially prepared defenses or as an OMG or second echelon against stronger defenses.

In some cases, the OPFOR has used TAs to drive rapidly toward deep objectives, destroy enemy strategic reserves, or maneuver rapidly to the flanks to encircle large enemy groupings that the slower-moving infantry would subsequently destroy.2 However, MIDs also include a significant number of tanks. Tank divisions have evolved into more balanced combined arms organizations with the expansion of artillery and mechanized infantry units. Thus, the traditional difference in the roles of MAs and TAs has largely disappeared. The design of OPFOR armies, regardless of divisional makeup, allows them to accomplish the tasks envisioned on a highly mobile battlefield.

Army Group First Echelon

First-echelon armies constitute the bulk of army group forces. Their success is essential to achieving the army group aim. If they do not accomplish a penetration, OMGs may be unable to conduct deep operations, and there might then be insufficient combat power in the second echelon to carry the offensive through to the depth of the army group subsequent mission. Moreover, the OPFOR is unsure whether the second echelon can arrive in time and in combat-effective condition to ensure success. The first echelon therefore has the requirement to reach at least the immediate mission of the army group without reinforcement.

If the depth of an army group operation is shallow and the enemy lacks strong reserves, a single army operation could be enough to achieve army group goals. Usually, however, the OPFOR expects a first-echelon army to conduct two successive operations with little or no pause between them.

Army immediate mission. In the first offensive operation against a partially prepared defense, the army's immediate mission would be to--

  • Destroy enemy precision and nuclear weapons.
  • Penetrate enemy covering forces.
  • Destroy the main forces of enemy first-echelon corps and immediate operational (corps) reserves.
  • Seize lines or areas that upset the stability of the defense and create favorable conditions for the continuance of offensive operations.

Army subsequent mission. The goal of the subsequent mission is to--

  • Destroy newly located precision or nuclear weapons.
  • Complete the destruction of enemy corps and approaching (army group) reserves.
  • Seize those areas that are the aim of the army group operation.

Army Group OMG

When acting as an army group OMG, an army may conduct one, more probably two successive operations with little or no pause between them. Against a weak or unprepared enemy, the OMG may actually lead the advance from near the start. Even if that is not the case, the army group holds the OMG well forward, probably 30 to 50 km from the line of contact, to ensure the earliest possible commitment to exploit a gap or penetration. Ideally committed on the first day against an unprepared defense, certainly by the third or fourth against a partially prepared defense, the OMG then operates considerably in advance of the main forces.

Army Group Second Echelon

A second-echelon army usually executes only one offensive operation--to carry the army group operation forward from its immediate to its subsequent mission. It may, however, be committed earlier than the achievement of the army group's immediate mission to reinforce the efforts of a first echelon that is losing momentum or faced by a superior enemy force. Another reason to commit a second-echelon army earlier would be for a specific purpose, such as reducing encircled or bypassed forces, conducting a pursuit, or even widening the penetration (strike) sector.

A second-echelon army would often be still moving up from the strategic rear when the offensive begins. If not committed immediately on arrival into the tactical zone, it may then be held anywhere between 50 and 120 km from the line of contact. Its march into battle (and often even its commitment) occurs at night, when possible, to achieve surprise and to minimize the threat of interdiction.

Special Conditions

In mountainous areas, or marshy areas intersected by rivers, efforts concentrate on dividing enemy groupings for destruction and seizing communications centers, main road junctions, and defiles through impassable terrain. In deserts and steppes, the depth of army operations might increase.

Changes in Missions

Army group missions are normally fixed, but those of armies may change, especially when the main effort shifts from one axis to another. Factors that might lead to a change in mission include--

  • Success along an axis other than the main effort, resulting in the reinforcement of this success.
  • Commitment of enemy reserves against a penetrating first-echelon army, requiring protection along the flank of the penetrating army.
  • Successful enemy resistance in the army's sector, or enemy counterattacks/counterstrikes, which lead to a change in the army group concept.
  • The loss of combat effectiveness from heavy casualties.
  • The capacity of the army group to support the army.

Prerequisites for Success

Penetrating a well-defended position can be a difficult task requiring detailed preparation and concentration. Success depends on the factors discussed in the following paragraphs.

Selection of Strike Sectors

The OPFOR carefully selects areas for penetration (strike sectors) that lead to both the achievement of geographical objectives and the destruction of the main enemy grouping. Ideally, it penetrates weak enemy groupings to get to the strong groupings from the flank or rear. Other vulnerabilities it can exploit are boundaries between enemy units and difficult terrain the enemy has defended only lightly because of its unsuitability for offensive action.


Detailed reconnaissance of both the terrain and the enemy is essential if the OPFOR is to make accurate calculations about required force levels and densities and to achieve reliable neutralization of the defense. OPFOR reconnaissance has the requirement to reveal 75 to 80 percent of the targets (100 percent in the case of particularly vital systems).

Correlation of Forces

The estimate of forces required to penetrate must be correct. Staff work must be meticulous to concentrate dispersed groupings rapidly in order to attack from the march.

Neutralization of Enemy Forces on Strike Sector

It is critical for artillery to neutralize the enemy on the strike sector and to its immediate flanks. The OPFOR defines neutralization as the destruction of up to 30 percent of all enemy personnel and weaponry in the target area. This is the norm usually required for a successful penetration. It would, for instance, reduce the density of major enemy antitank weapons from 15 per km to about 10 per km, which would reduce casualties to around 25 percent.

The problems of movement, coordination, and logistics support are by no means insurmountable in defeating the first echelon of a prepared defense. However, the difficulty increases if the OPFOR has to make another penetration at the rear of the enemy tactical zone of defense 40 to 60 km from the original line of contact.

Moving both tank and mechanized infantry elements and their supporting artillery, as well as the required logistics, through narrow strike sectors requires a fully-functioning C2 system or strong initiative by field commanders.3

Neutralization of Enemy Tactical Reserves and Command Posts

Artillery, air attacks, and forward, raiding, and heliborne detachments must neutralize enemy tactical reserves and command posts if the OPFOR is to destroy the stability of the defense and gain early momentum.

Rapid Penetration

Rapid penetration by the first echelon is essential to destroy the cohesion of the defense and to generate operational maneuver from an early stage. Otherwise, the battle degenerates into one of attrition, wasting precious time. This penetration, in turn, depends on the continuity of fire support and the timely reinforcement of efforts by second echelons (reserves) at all levels.

Information Warfare

Information Warfare (IW) conducted at the army level follows the same form and principles as that of the army group (see Chapter 4). Detailed information on tactical-level IW operations is provided in FM 100-62.


The army commander considers the same factors as his superior, the army group commander, but naturally at one level lower. The army commander presents his decision graphically on a 1:250,000- or 1:100,000-scale map. (See Figure 5-1 for a simplified example.) Usually he needs the 1:100,000 scale because of the increased detail of his plan compared to the army group plan. On the map, he indicates--

  • Groupings of enemy forces and their possible courses of action.
  • The army's operational formation.
  • The army's immediate and subsequent missions and their contents, depths, and time for accomplishment.
  • The location of strike sectors and axes of main and supporting attacks.
  • The combat formation of first-echelon divisions and brigades and the method of their movement into specified areas.
  • The missions of first-echelon divisions.
  • The method of commitment of second-echelon divisions (or combined arms reserve).
  • Firing position areas for army and division artillery groups (AAGs and DAGs) and the army rocket artillery group (ARAG).4
  • The composition, missions, landing areas, and time of insertion of airborne and/or amphibious landing forces.
  • Deception and decoy units or groupings.

Figure 5-1. Map of the army commander's decision.

(For more detail, see Chapter 7; see also Commander's Decision section in Chapter 4.)


The concept of operations determines the operational alignment of the army forces. The OPFOR term for this basic organization for combat is operational formation5. The operational formation of an army (or army group) is the grouping created for conducting a particular operation. It must be in accordance with the higher commander's concept. The army's configuration must ensure the destruction of the main enemy grouping by establishing the required COF superiority on strike sectors and by ensuring early and a rapid exploitation into the enemy's rear.


The army's organization for combat is quite flexible, much like the army group's. In an offensive, army operational formations include most or all of the following elements:

  • Army first echelon (containing most of the army's forces).
  • Forward detachment.
  • Army OMG.
  • Army second echelon or a combined arms reserve.
  • Army antitank reserve (with mobile obstacle detachments).
  • Artillery groups.
  • Engineer and other special reserves.
  • Combat helicopter regiment(s).
  • Airborne and heliborne landing forces.
  • Other elements.

Against at least partially prepared defenses, MIDs usually accomplish the penetrations, supported by strong artillery groups at all levels up to and including the AAG and ARAG. In this case, the army uses its TDs (if it has any) in the second echelon, for an exploitation role. On the other hand, the army might anticipate light resistance or a meeting engagement. In such instances, it is normal to place TDs in the first echelon and decentralize much of the artillery.

First- and second-echelon forces operate in concert, up to assigned mission depths, to destroy defending enemy forces before them. An army commander normally plans to commit his second-echelon forces after his first echelon has attained the army's immediate mission. If he employs an army OMG, he could commit it as early as the first day, but more likely on the second or third day, of an operation.

Army First Echelon

One or more divisions in the army's first echelon attack on a predetermined army main axis. The forces conducting the main attack have the mission to achieve a penetration of the enemy's prepared defensive positions. Other first-echelon divisions conduct supporting attacks, fixing attacks, or perhaps even defensive actions.

First-echelon brigades of the army's first-echelon divisions attack from the march at top speed to achieve deeper penetration of the enemy's main defenses. They plan to exploit surprise and enemy disorganization. Second-echelon brigades of the army's first-echelon divisions exploit the best penetrations into the deep tactical rear of the enemy (to the rear boundary of the enemy division).

The scope of a division's actions varies widely according to its role in the army operation and the strength of the enemy. Although it is unlikely that an army would face an enemy force with fully deployed, well-prepared defenses across its entire zone of action, that could be the case for a division within the army's operational formation. Other divisions, however, could face defenses ranging from unprepared to partially prepared. In any event, the army's second echelon is prepared to exploit success wherever it may occur.

Against strong, deeply-echeloned, and well-prepared defenses, an army conducts penetration battles on strike sectors normally totaling from 4 to 6 km in width to ensure requisite COF superiority. Under these conditions, it is even possible that the zone of advance of a division attacking on the army's main axis could coincide with its strike sector. Such narrow frontages reflect an attack echeloned in great depth. Up to half of the division would be acting in the second echelon. First-echelon brigades and their leading battalions would also be in two echelons. Such a penetration requires the support of strong artillery groups, including the brigade artillery groups (BRAGs) of first-echelon brigades, the DAG (or perhaps two DAGs) of the division, and probably an AAG and/or ARAG.

In a penetration of a well-prepared defense, the OPFOR expects a leading first-echelon brigade, as its immediate mission, to destroy a first-echelon defending battalion (a depth of 8 to 10 km). Its subsequent mission is to destroy the reserves of a forward brigade and penetrate to the depth of the division's immediate mission.

The immediate mission of a first-echelon division is to--

  • Destroy a forward brigade.
  • Destroy the brigade reserve and seize its position.
  • Penetrate to the positions of supporting artillery.

The depth of this mission ranges from 16 to 20 km. The destruction of the enemy's first-echelon brigades and attacks on gun lines would disrupt the enemy's fire system and mutually supporting defenses. This would create favorable conditions for the destruction of the remainder of the enemy division.

The division's subsequent mission is to--

  • Destroy the enemy's divisional reserve.
  • Complete the penetration of the tactical zone of defense.
  • Capture favorable terrain for launching exploitation to the flanks and rear.

This mission would normally be from 25 to 30 km deep. The division also receives a mission of the day. This mission, in cooperation with adjacent divisions, is likely to be the destruction of enemy corps reserves.

Another mission the army might assign to the division commander would be to dispatch a forward detachment (FD) after the first echelon has disrupted the stability of the defense. If the mission is to form an army-level FD, the division commander assigns this task to one of his brigades. The division may also choose to dispatch an FD of its own. This usually consists of a reinforced battalion from one of its brigades. Either type of FD attempts to infiltrate into the enemy rear, off the main axis, and seek to seize dominating terrain or obstacle crossings or forestall the actions of enemy tactical reserves. (For more detail, see Forward Detachments below.)

Finally, the division may have the requirement to ensure the trouble-free deployment and commitment of the army OMG or second echelon. To accomplish this task, divisional engineers and air defense assets prepare and protect routes, a reinforced brigade launches a supporting attack, and the DAG fires missions against forces opposing the OMG/second echelon.

In attacks on partially prepared or unprepared defenses, penetration is less of a problem. Therefore, a division's immediate mission might be the destruction of an enemy first-echelon brigade and (with other forces) a reserve brigade. The subsequent mission is to penetrate to the full depth of a defending division; the mission of the day might be up to 60 km deep.

In attacks on a weaker, partially prepared enemy, the zone of advance of a division on the army's main attack axis is normally 15 to 25 km. The strike sector is approximately 2 to 4 km per division. (After the penetration, the zone of advance widens again.) For a division on a supporting attack axis, the zone of advance might extend from 30 to 50 km. Thus, the overall zone of attack for the army could be 60 to 100 km. A total of 8 to 12 km is in the strike sectors.

Forward Detachments

Armies, divisions, and brigades employ FDs as tactical maneuver forces. Against an unprepared defense, the army's brigade-size FD could actually have an operational-tactical mission; that means that it might perform missions as deep as the immediate operational depth of the defense; that is, to the enemy corps rear area. Army and division FDs function during all types of offensive action--an attack against a defending enemy, a meeting engagement, or a pursuit. The same concept applies to brigade FDs, except that employment in an attack against a defending enemy is normally only against an unprepared defense. Whatever the level, FDs are tailored forces, reinforced to allow independent action. Depending on the enemy and the terrain, the nucleus of an FD can be either tank or mechanized infantry forces; however, tank battalions and tank brigades are the most likely.

Forward detachments serving operational maneuver forces help maintain the forward momentum of the entire force. They fragment enemy forces, penetrate covering forces, preempt or overcome intermediate defensive positions, and destroy the equilibrium of deploying enemy reserves. Forward detachments provide the essential linkage between OMGs and main forces and lend cohesiveness to the entire offensive.

Against unprepared defense. The characteristics of the offensive are surprise, speed, and attempts to preempt or dislocate the enemy. Forward detachments from first-echelon divisions may attempt to strike deep into the enemy tactical zone of defense (main defense area) before enemy defenses are fully organized and solidified. Reinforced battalions (or sometimes entire brigades) given such missions receive full support from artillery and direct-support aviation. It is also possible that an army could employ a brigade-size "operational-tactical" FD to achieve similar, but deeper, results to the rear of the tactical zone of defense.

Against an unprepared defense, where the enemy has deployed only his covering force, FDs at all levels might initiate the attack. If the enemy has advanced during the night before the offensive, they then attack on multiple axes across the army's offensive zone to penetrate rapidly enemy covering forces.

They then drive at top speed in prebattle or march formation to seize and hold key terrain within the enemy division's main defense area, thus preempting enemy occupation of positions there. There may also be battalion-size heliborne landings, designed for linkup with the forward detachments. Such tactics in support of an operation help to disrupt or preempt enemy defensive structure while opening multiple avenues for swift attacks by larger first-echelon forces. Figure 5-2 shows typical depths of FD missions against an unprepared defense.

FD Subordination


Depth (km)


immediate operational depth



rear of tactical zone of defense



front of tactical zone of defense


Figure 5-2. Forward detachment missions against unprepared defense.

Against partially prepared defense. More often, the OPFOR finds the enemy defense partially prepared, with the covering force in place and the tactical zone of defense partially occupied. A brigade FD does not attack under these conditions, but an army or division FD could if it receives heavy fire support. The FD's mission is to overcome the covering force and penetrate into the tactical zone of defense to prevent the enemy from establishing a firm, fully integrated defense.

An FD could also facilitate the commitment of the main force (first- or second-echelon divisions) and OMGs. Figure 5-3 shows typical mission depths under such conditions, which is one step shallower than for an unprepared defense.

FD Subordination


Depth (km)


rear of tactical zone of defense



front of tactical zone of defense


Figure 5-3. Forward detachment missions against partially prepared defense.

During the attack, FDs use reconnaissance to detect gaps in enemy defenses occurring naturally or created by artillery fire. If a gap exists, or if fire support has neutralized sectors of the defense, the FD moves quickly through the gap to secure objectives in the enemy brigade or division rear.

Against a prepared defense. If the OPFOR encounters a prepared, fully occupied defense, FDs do not participate in operations until first-echelon divisions have completed the penetration of enemy first-echelon brigades (the front of the tactical zone of defense). (In rare instances, a division FD may assist the main forces in penetrating the covering force or in initiating subsequent attacks into the tactical zone of defense. However, it is unlikely that it would emerge still capable of further operations.)

Once the penetration operation is complete, forward detachments at all levels of command lead the operational exploitation or pursuit, helping to encircle and destroy enemy forces. In this role, they advance from 30 to 60 km ahead of the main force.

Throughout the operation, strong FDs continue to press the advance into the enemy rear on several axes. Numerous deep penetrations by FDs and/or OMGs early in the operation may result in an intermingling of enemy and friendly forces. This situation complicates or forestalls enemy use of precision or nuclear weapons. The OPFOR would accept heavy losses in such deep-penetration forces if it could cause an early collapse of the enemy's defensive structure before he could resort to use of nuclear weapons.

Army Operational Maneuver Group

An army might form an OMG either from resources that are normally part of it or from army group assets that are supporting it. An army commander might establish an OMG before an operation as part of the initial plan, or he might instead form one during an operation to exploit an unforeseen opportunity. At army level, the OMG might be as large as a reinforced division and, usually, based on a TD because of its speed and shock effect. The army commander selects a division for this mission. It has the latest equipment, a high state of combat readiness, and first-rate division and brigade commanders. An army that uses one of its divisions as an OMG may have to resort to a smaller second echelon or combined arms reserve. An army OMG could operate 100 km or more beyond other army forces.

Objectives and raids. Once committed, the OMG's ultimate task depends on the army group commander's concept of the operation. It may preempt the defense, seizing strategic objectives, destroying enemy reserves, and/or seizing key terrain to facilitate the advance of the army's main force. Unlike the second echelon, the army OMG acts as a large operational raiding force. Typically, it has one or more objectives, perhaps located on the army's main axis. On the way to its geographical objective(s), the OMG attempts to avoid a decisive engagement with large enemy forces. However, it may conduct raids en route. In this case, it launches battalion- or even brigade-size raiding detachments to attack targets crucial to the viability of the enemy defense. The relative importance of raiding versus achieving a mission depends solely on the mission(s) of the OMG. Figure 5-4 illustrates the activities of an army OMG.


Figure 5-4. Actions of an army OMG in the enemy rear.

Cooperation with other forces. Although operating ahead of the main forces, the OMG does not fight in isolation. Air reconnaissance, long-range reconnaissance patrols, and SPF patrols provide intelligence and targeting data. Some heliborne and airborne landings directly help the OMG, smoothing its advance by preempting defensive or counterattack preparations; others help indirectly by confusing the enemy and inhibiting his reaction. Air interdiction also attempts to prevent counterattacks or counterpenetration. The OMG receives the highest priority for both air defense and ground-attack aircraft. Indeed, as the OMG advances beyond supporting range of helicopters operating along the line of contact, it will have its own air component--helicopters moving with the OMG. It may also be possible to make at least temporary use of captured airfields or improvised strips to base fighters or to fly in resupply. OMGs, airborne/heliborne, and air operations are all crucially interdependent, the successes of each contributing materially to that of the others.

Command and control and logistics. Command and control of an army OMG is accomplished by a combination of radios, an airborne command post, and air and ground couriers. Sustaining the OMG requires highly mobile transport and supply. The OPFOR attempts to maintain a ground line of communication, but it plans for resupply by air.

Relationship to second echelon. The relationship between the army OMG and the second echelon varies depending on the concept of the operation. If the OMG is operating away from the main axis of advance, its activities and those of the second echelon may not be directly related. If the OMG is operating on the main axis of advance, the second echelon may have to destroy forces bypassed by the OMG or to secure the OMG's lines of communications.

Army Second Echelon

The army's second echelon normally consists of one or more divisions. It advances behind army first-echelon forces and marches with its units dispersed laterally on multiple routes to minimize vulnerability to enemy detection and attacks. Based on the development of the battle and on his assigned mission, the army commander commits his follow-on forces at the most opportune time and place. This achieves deeper exploitation of a penetration and leads to the dissolution of enemy tactical and immediate operational defenses.

The OMG and the second echelon are different types of follow-on forces. An army commander, given a limited number of divisions, might not be able to form both. If he expects initial enemy defenses to be relatively weak, he is less likely to form a second echelon, but more likely to use an OMG. If he uses an OMG and all goes well, there should be less need for a second echelon, and a smaller combined arms reserve could suffice. Should the strength and stability of the defense preclude the planned use of an OMG, the division originally assigned the mission could simply become part of the reserve.

An army may form either a second echelon or an OMG or even both in some circumstances. The commander may hold a division designated as an army OMG well forward, probably not more than 30 to 50 km from the line of contact, ready for early commitment. (From that distance, it takes from about two to three hours for a division marching on two or three routes to move forward from its assembly area and pass through a breach in enemy defenses.) Second-echelon divisions are held 40 to 60 or even 80 km to the rear while the first echelon is achieving the penetration. Thereafter, they follow the leading divisions at a distance of 50 to 60 km until committed (in this case, the process should take 4 hours). The army commander may temporarily detach divisional artillery from second-echelon divisions to augment artillery support for the penetration. This divisional artillery receives two, possibly three, alternative lines of commitment and routes to them.

Ideally, to generate maximum combat power going into the attack, commitment of either a second echelon or an OMG follows a clean breach in the defense and occurs at night on a sector 12 to 20 km wide on three routes. At the time of commitment, the second echelon or OMG receives augmentation by elements of the first echelon and/or the AAG. Maximum air and artillery support accompanies commitment. Figure 5-5 illustrates a preferred mode of commitment of an army's second echelon, on a 15-km frontage through a gap in the deployment of the first echelon. Sometimes, however, such forces may have to attack on a narrower frontage (strike sector), as little as 5 km wide, to complete the penetration. Given the enemy's capabilities to acquire targets and to employ precision weapons, commitment of the second echelon or OMG on such a narrow frontage is the least preferred course of action. (Refer to Figure 4-8 for an example of an army OMG completing a penetration on a 5-km sector.)

Figure 5-5. Commitment of an army's second echelon.

Since it is impossible to predict the progress of the operation in the enemy's depth with certainty, second echelons receive only an immediate mission and a subsequent axis of advance. Once the army commander commits his second echelon, he establishes a new one, or a reserve, either by withdrawing other forces from combat or through reinforcement from the army group.

Army Reserves

If an army does not have a second echelon, it normally retains one or more brigades as a combined arms reserve in an offensive. This also could be a mission for a separate MIBR or TBR. Other reserve brigades may come from army first-echelon divisions in supporting attack sectors.

Antitank reserves and other special reserves are important in augmenting the first echelon so that the army does not have to commit its second echelon prematurely. They can also provide strong defense against counterattacks so it is not necessary to divert elements of the main forces from their mission. (For more detail on various types of reserves, see Chapter 4.)

A mechanized army's organic antitank (AT) regiment normally constitutes its AT reserve. However, an army may also receive an AT brigade from the army group or from the Reserves of the Supreme High Command. In that case, the reinforcing brigade becomes the army AT reserve; the AT reserves of divisions operating on the army's main axis are reinforced using the assets of the army's organic AT regiment.

Artillery Groups

An army of an army group's first echelon receives artillery units from the army group artillery division(s). The army commander then allocates army and army group artillery to his divisions to form DAGs. He may retain some artillery at army level to form one or more AAGs and an ARAG.

The majority of this artillery is long-range guns and MRLs, though the AAG may have some howitzers assigned from a second-echelon division. Within the army, artillery from second-echelon divisions may go to reinforce first-echelon divisions until the commitment of the second echelon to battle. The artillery would then rejoin its parent division.

Together with fixed-wing aviation, these artillery groups have the most important task--neutralizing enemy precision weapon systems and artillery. They can also maneuver concentrated fire to support the attacks of both first and second echelons or OMGs and to engage enemy reserves.

With organic and army group-allocated assets not passed down to its divisions, an army conducting an army group main or supporting attack forms a strong AAG. The purpose of an AAG is to--

  • Engage enemy SSMs and artillery, especially those capable of delivering precision munitions, along with associated C2 facilities.
  • Reinforce the fires of DAGs on the army's main attack axis.

An army could have from four to eight battalions of tube artillery for this purpose.6 If the number is closer to four battalions, the army forms one AAG; if it is closer to eight it is probable that an army would form subgroups or two AAGs. The latter may be necessary to support more than one division or to perform more than one mission (for example, divisional support, counterbattery, or demolition of fortifications).

An army does not normally allocate the MRLs of its organic MRL regiment to its subordinate divisions. With these and additional MRL battalions allocated to the army from the army group-level MRL brigade, the army commander may form an ARAG. Thus, the ARAG has at least three MRL battalions and perhaps as many as seven. With the larger number, an army might form two ARAGs. The army commander normally reserves the ARAG for centralized employment in the army's main attack axis. However, it could also conduct rapid maneuver to any axis, as required, to inflict losses on main enemy groupings.

Combat Helicopter Regiments

The OPFOR considers aviation to be a means of fire support. When operating in an air corridor, army aviation can use its attack helicopters for missions across the line of contact. They can attack enemy gun lines and reserves, especially those trying to deploy. This, of course, occurs only when preceded by suppression of enemy air defenses. Attack helicopters also provide direct air support to units fighting through enemy defenses. Their support is important in the transition from the artillery preparation to support phases and in the accompaniment phase. They are, however, most useful in engaging targets beyond effective artillery range. They closely coordinate their activities with those of the artillery, air defense, and fixed-wing aviation.

The army's combat helicopter regiment(s) also have transport helicopters. With additional heavy-lift reinforcement from army group, and with strong artillery and air support to suppress enemy air defenders, the army can insert a mechanized infantry battalion into the enemy rear.

Airborne and Heliborne Landing Forces

Any brigade-size landing of airborne troops is more likely to be air-dropped than helicopter-delivered, particularly if it is more than about 50 km beyond the line of contact. (See Chapter 16 for more detail on airborne operations.)

The OPFOR can launch battalion-size heliborne landings up to 50 km or so into the enemy rear. This restriction is due to the payload/range limitations and helicopter vulnerability. Even then, the airborne troops expect early linkup with forward detachments or OMGs. Usually, an airborne battalion can hold out no more than 18 to 24 hours without resupply.

Mechanized infantry battalions may serve in the heliborne landing role (particularly for shallow missions). They usually operate not more than 20 km from the line of contact, within range of supporting artillery. Heliborne insertion of a mechanized infantry company normally is to a depth of not more than 10 km.

The less prepared the enemy defense, and the less dense and more poorly organized its air defense, the greater the scope a heliborne landing might have. Using such landings, an army can conduct company- to battalion-size raids against vulnerable, high-priority targets such as precision weapons, headquarters, and key logistics assets. Such raids commonly seize defiles, river crossings, and prepared but as yet unoccupied counterpenetration positions in the enemy's rear. In this way, they can help convert tactical into operational success and help generate operational momentum by--

  • Blocking the moves of enemy reserves.
  • Blocking the withdrawal or redeployment of enemy forces.
  • Seizing positions on which the enemy could fight delaying actions.

The mechanized infantry battalions involved normally come from a second-echelon brigade or, perhaps, even from a second-echelon division. Such a heliborne landing is usually in support of a division on the army's main axis. A division or army may order it, but the army provides both lift and approval.

Other Elements

A first-echelon army on the main attack axis is likely to receive, from army group, additional--

  • Engineers and river-crossing equipment.
  • Air defense weapons.
  • Chemical defense units.
  • Transportation assets.

The army commander allocates these assets primarily to support the main effort. Subordinates also receive these assets according to their specific needs.

Influence of Nature of Enemy Defense

As at other levels, the factors that determine an army's operational formation include the--

  • Aim of and plan for the operation.
  • Strength, depth, and degree of preparedness of enemy defenses and operational reserves.
  • Availability of resources.
  • Nature of the terrain in the zone of advance.7

However, the strongest influence is usually the nature of the enemy defense.

The nature of the enemy's defenses also largely determines the echelonment of OPFOR offensive formations. The enemy may not have well-prepared defenses in depth backed by operational-level reserves. If not, the army would attack in a single strong echelon followed by a combined arms reserve.

If the enemy is well prepared in depth or does have operational reserves, the army would attack in two echelons. In other words, if the enemy defense has an operational second echelon or reserve, the OPFOR employs an operational second echelon to sustain the momentum of the offensive.

Figures 5-6 through 5-9 show several possible variants of operational formation an army might use against defenses with varying degrees of preparedness. Figure 5-6 depicts an example formation against a prepared defense, figure 5-7 and 5-8 against a partially prepared defense, and figure 5-9 against an unprepared defense.

Figure 5-6. Example army operational formation against prepared defense.

Figure 5-7. Example army operational formation against partially prepared defense (variant 1).

Figure 5-8. Example army operational formation against partially prepared defense (variant 2).

Figure 5-9. Example army operational formation against unprepared defense.


Planners have established norms in distances, rates of advance, and time factors for army offensive operations. These norms principally depend on an assessment of friendly and enemy capabilities. In particular, they depend on the preparedness of enemy defenses. They may also reflect other factors such as terrain and weather. These factors guide planning for an operation. Not all norms for a given theater apply to other theaters. Even within a specific theater, OPFOR planners may vary considerably from these norms, depending on the particular conditions.

Army Missions

An army in the first echelon of an army-group offensive normally has a mission to attack through enemy defenses to the immediate operational depth--the enemy's army rear area. The achievement of an army's mission is the culmination of successive attacks conducted by its divisions.

A typical army immediate mission is to destroy the integrity of an enemy corps. This includes seizing important areas that facilitate offensive operations deeper into the enemy rear area. The task of the first day of the operation may be to penetrate the forward defending enemy division and, subsequently, to advance to the counterattacking corps reserves.

The army subsequent mission depends primarily on the nature of the enemy defenses. It could include any or all of the following actions:

  • The complete defeat, in zone, of the enemy corps.
  • The destruction of army group reserves.
  • The destruction of the integrity and operational stability of the opposing army group.


As with army groups, armies vary in size and combat missions. These, and the following factors, determine the dimensions of an army offensive operation:

  • The nature of the terrain.
  • The strength and nature of the defense.
  • The need to concentrate to create the required COF superiority over the enemy.
  • The need for maneuver space.

Thus, there can be considerable variations in such factors as the width of the zone of advance and depth of missions. The generalizations given below are guidelines only.

Depth and Duration

A first-echelon army may execute two successive operations to a depth of 250 to 350 km. Its immediate and subsequent missions largely depend on the nature of the defending enemy forces the army must destroy.

The depth of a first echelon army's immediate mission normally is to the rear boundary of a defending corps. By penetrating to this depth, the army would complete the destruction of enemy first-echelon divisions, thus destroying the cohesion and integrity of the enemy corps. Under normal conditions (against a partially prepared defense) the depth of this immediate mission would be 100 to 150 km accomplished over a period of 3 to 4 days.

The subsequent mission of such an army would usually be to complete the destruction of the enemy corps and engage the enemy army group reserve if possible. This mission involves an additional 150 to 200 km and another 3 to 4 days against light opposition (no more than a partially prepared defense). Thus, the total depth of the subsequent mission could be 250 to 350 km over a total of 6 to 8 days.

Under favorable conditions, the army's first-echelon divisions (which, like the army itself, may conduct one or more successive attacks) may accomplish the army's subsequent mission. Against more prepared defenses, however, the army normally forms a second echelon to complete this task.

Expected Rate of Advance

Against a partially prepared or overextended defense that lacks strong operational reserves, the expected average rate of advance is 40 to 60 km per day. However, this rate may not be uniform. It might be no more than 25 to 30 km per day when fighting through defended areas. Once the attacking force has achieved a penetration, the rate of advance increases considerably (up to 60 to 70 km per day in pursuit or exploiting the offensive into the enemy rear). All these rates are for mixed terrain.

In close terrain, such as mountains, marshes, jungles, and arctic areas, the average rate of advance decreases to about 30 to 50 km per day. In open terrain, such as deserts or steppes, it increases substantially.

Width of Zone of Action

The zone of action of a main axis army, with 4 divisions in the first echelon, is likely to be from 60 to 100 km in mixed terrain.8 In other types of terrain, particularly in mountains, the zone of action may be wider. The zone of action depends on the number of axes of advance in the army's first echelon. In assigning division frontages, the OPFOR considers assessments of friendly and enemy forces as well as the nature of the terrain.

The average division zone of action for offensive operations in a main attack is 15 to 25 km wide. Thus, the width of a first-echelon army making the main attack with four divisions in its first echelon might vary from 60 to 100 km. With only three divisions in the first echelon, it would be 45 to 75 km; with 2 divisions in the first echelon, it may be as little as 30 to 50 km. The width of the zone of action could be up to 100 km or larger for--

  • Armies not making the main attack.
  • In passive sectors.
  • On axes where the enemy has no significant forces.
  • In areas with much impassable terrain.

In any conventional operation, there are long defensive and secondary sectors, at least at the start, and particularly in attacks on well-prepared defenses. Strike sectors for an army penetration against prepared defenses are likely to total about 8 to 12 km, on one or two sectors. Once the attacking force has penetrated the enemy's tactical zone of defense, and the enemy starts to withdraw his outflanked forces, the breadth of offensive actions increases. OPFOR units in previously "passive sectors" then transition to the pursuit of withdrawing enemy forces.


The form an army operation takes depends on the location and strength of enemy groupings and their likely reactions, the nature of the terrain and location of obstacles, and the army-group commander's concept of operations. Having established the areas in which the decisive battles are likely, the army commander works out the method of attack in terms of frontage, depth, and main and supporting axes. Operations at army group level, as portrayed in Chapter 4, are similar in concept at army level but, of course, on a smaller scale. An army uses the same two basic forms described for the army group (or combinations thereof) plus one form (the "single penetration") peculiar to the army.

Single Penetration

An army may deliver a single, heavy strike on one axis to the entire depth of the defending enemy corps, simultaneously widening the gap to the flanks and destroying fragmented enemy groupings. This form of operation, portrayed in Figure 5-10, is used when having to penetrate strong, deeply echeloned, prepared defenses at the start of an operation.

Figure 5-10. An army penetration operation against a prepared defense.


Figure 5-11 illustrates the delivery of two heavy strikes on converging axes to encircle the main enemy grouping (including the reserve brigade of the enemy division) while simultaneously exploiting into the enemy's rear. This form of operation is suitable--

  • When the trace of the line of contact forms a salient.
  • When the army has sufficient strength for two thrusts.
  • Against an unbalanced enemy, with a strong grouping (its center of gravity) well forward, flanked by two weaker ones (as will often be the case during a counterattack.

Figure 5-11. An army encirclement operation.

A variation on encirclement, depicted in Figure 5-12, is the trapping of the enemy against an obstacle to destroy him there. In coastal operations, the obstacle is, of course, the sea. Such an operation can also occur inland, trapping the enemy against a major river or canal or possibly a mountain range. If interdiction or airborne landings deny the enemy bridges, ferries, or passes over the obstacle, the OPFOR can destroy the enemy grouping. Enemy personnel may be able to exfiltrate, but at the price of abandoning their heavy equipment. Another use for the concentrated strike from one flank is to encircle a much larger enemy grouping in cooperation with the forces of another army. This type of maneuver can also force a defending enemy to abandon prepared defensive positions and reorient; the OPFOR can then destroy the enemy grouping with flank and rear attacks.

Figure 5-12. An army encirclement against a natural obstacle.

Attack Across a Broad Frontage on Multiple Axes

An army may deliver two or more penetrating strikes to achieve the disintegration of the main enemy grouping, splitting it up into isolated pockets. (See Figure 5-13.) This sort of operation can occur when the enemy's defense is of a less than fully prepared nature, lacking depth and a strong reserve on that army's axis.

Figure 5-13. An army attack on multiple axes.


An army carries out the same three basic forms of combat action as the army group. Again, the OPFOR defines these in terms of the postures of the attacker and defender, not the time available.

Meeting Engagement

As an operational-level force, an army conducts a meeting engagement. (See "Meeting Engagement" in Chapter 4.) Its subordinate divisions and brigades conduct meeting battles at the tactical level. Figure 5-14 shows a simplified example of an army commander's decision for a meeting engagement.

Figure 5-14. An army commander's decision for a meeting engagement.

Attack Against a Defending Enemy

The army, like the army group, conducts two basic types of attack--from the march (out of direct contact) and from a position in direct contact with the enemy. The characteristics of these attacks are the same as for the army group. (For further details, see "Attack Against a Defending Enemy" in Chapter 4.)

Ideally, the OPFOR mounts an attack from the march from concentration areas out of contact. In this case, final assembly areas for leading divisions are within 20 to 40 km of the enemy forward edge (or international border). They are thus out of range of preemptive artillery strikes, but still only 1.5 to 3 hours night march from the line of commitment.

Where the enemy has succeeded in deploying a covering force, battalion- to brigade-size FDs of the first-echelon divisions will destroy that force. The division main forces follow the FDs in tactical march or prebattle formation, aiming to attack the enemy's forward edge close behind the retreating covering force to gain a lodgment.

If, however, enemy resistance in the covering force is strong, it may be necessary for the OPFOR to commit first-echelon brigades, even divisions. The commander must then consolidate and reorganize units into appropriate groupings before they make contact with the main defense.

There are circumstances in which the OPFOR may have to launch an attack from a position in direct contact. This means that an army resumes an offensive that had stopped, or it transitions to the attack after conducting a successful defensive engagement. In the latter case, the timing is of great importance. The army should go over to the offensive only when the enemy has taken such heavy losses that he has lost his capability to continue his attack, but before he has regrouped or reorganized to meet the counterattack/counterstrike.


The army uses the same pursuit techniques as at army group level. First-echelon armies rely on their FDs and airborne or heliborne landings to cut off the withdrawing enemy. Operational pursuits may extend to a depth of several hundred km. (For further discussion, see "Pursuit" in Chapter 4.)

The OPFOR regards pursuit as a separate and decisive phase of combat. The purpose of an offensive is not just to drive the enemy back, but also to destroy him so he cannot reinforce and reorganize his force to continue the struggle. Encirclement and pursuit are the two basic methods of completing the destruction of an enemy grouping.

There are three basic elements of the pursuit (Figure 5-15). First, a portion of the army vigorously conducts a frontal (direct) pursuit to prevent the enemy from disengaging and to slow him down by forcing him to deploy not just rear guards but elements of his main body. Second, the army's main body conducts a pursuit on routes parallel to the withdrawing enemy columns, trying to overtake them and delivering flank attacks to split the enemy force into isolated groupings for destruction in detail. Third, the army sends FDs and heliborne or airborne forces ahead to seize defiles and/or obstacle crossings the enemy needs to escape or to receive reinforcements. Strong flank detachments and/or antitank reserves may also be necessary to prevent approaching enemy forces from disrupting the pursuit.

Figure 5-15. A tank army conducting a pursuit.

The OPFOR organizes pursuit in a centralized manner, but it conducts a decentralized pursuit. Staffs conduct advanced planning to avoid losing precious time, which could give the enemy the advantage. Therefore, OPFOR planners must identify routes for enemy withdrawal and for the OPFOR advance. They must issue an outline plan for operational formation and the scheme of maneuver. They must form preplanned FDs and heliborne detachments.

The OPFOR must intensify reconnaissance (and counterreconnaissance) efforts for the pursuit to be successful. To prevent enemy escape, early detection of an enemy withdrawal is also important.

Therefore, the OPFOR demands that its commanders at all levels initiate pursuit immediately on detecting an attempt to withdraw, informing higher headquarters as they do so. (This is an occasion when the exercise of initiative, without waiting for orders, is mandatory.) The pursuit continues until one of the following conditions exists:

  • The OPFOR has destroyed the enemy.
  • The higher commander terminates the pursuit because the pursuing forces or their logistics support becomes overstretched or because the COF has changed for the worse.
  • Enemy reserves have arrived.

Developing the Offensive

For the timely achievement of operational and strategic goals, it is necessary to develop the offensive into deep battle from the earliest opportunity. To do this, OPFOR divisions use forward, raiding, and heliborne detachments. Then, as a result of these tactical maneuvers, armies conduct deep operations with OMGs operating along with aviation and airborne landing forces. Figure 5-16 portrays the desired actions of an army in the enemy's rear to convert tactical into operational success. In executing operations in the enemy rear, the OPFOR may encounter five situations. This chapter has already dealt with one--pursuit; the following paragraphs discuss the other four.

Figure 5-16. Actions in the enemy rear.

Destroying Enemy Reserves and Repelling Counterattacks

The counterattack poses great difficulty, because it represents the enemy's effort to regain the initiative. The OPFOR must delay, disrupt, and damage approaching enemy reserves by air attacks, then by long-range artillery. First-echelon forces, or perhaps an OMG, should then destroy enemy reserves in meeting engagements, if the COF allows.

Strong antitank reserves and flank detachments should block the counterattack. If, however, the enemy enjoys too great a COF superiority and/or is the victor in the meeting engagement, it may be necessary to change the axis of main effort. The OPFOR should allow nothing to prevent deep penetration. The OPFOR may commit the second echelon, or elements of it, to destroy the enemy counterattack and resume the offensive.

River Crossings

It is important, when possible, to preempt the establishment of defense along a river line.9 The OPFOR can do this through the use of heliborne or forward detachments at the tactical level and airborne units and OMGs at the operational level. Following close behind a retreating enemy, the main forces would try to encircle the enemy against the obstacle and destroy him on the near bank, thus crossing the river unopposed. Should a forced crossing become inevitable, the commander must make the decision for it well in advance. He should issue combat missions from at least 1 to 2 days in advance of leading divisions' reaching the obstacle, to allow time for organization of combat groupings, engineer and air support, airborne landings, and deception measures. Preparation is essential if the OPFOR is to achieve the necessary speed and surprise to conduct crossings from the march.

Generally, the OPFOR forces a river line on a broad frontage, since this reduces the danger of vulnerable concentrations and traffic jams. Thus, it also complicates the intelligence picture for the defender in the crucial early stages, so that he is unable to deploy his firepower and reserves to best advantage. All leading divisions attempt to force with at least two brigades, and each of those, in turn, attempt a crossing at two points. When these units have seized tactical footholds, the OPFOR attempts to link them up and deepen them into an operational-size bridgehead. Ideally, units do not pause to consolidate bridgeheads; rapid forward progress is always of paramount importance. The enemy, however, can put up a determined fight for river lines, and heavy counterattacks can force the OPFOR onto the defensive to hold the favorable line gained for exploitation by subsequent echelons.

Operations at Night

The OPFOR has to continue operations around the clock to deny the enemy any breathing space and prevent his consolidation on new lines or the restoration of the defense. However, night-fighting equipment may not be state-of-the-art. When required to attack at night, the OPFOR may choose to convert it into something approaching daylight conditions with the extensive use of illumination.

The amount of illumination used varies according to the amount of thermal imaging capability possessed by OPFOR units. Moreover, OPFOR soldiers need rest, too; units must carry out equipment maintenance and resupply. Accordingly, the OPFOR may avoid conducting complex maneuvers at night. Divisions and brigades may alternate attacking and resting.

Most offensive action occurs only to--

  • Exploit gaps and weak spots where the enemy is in disarray.
  • Seize limited objectives that provide a favorable line for resuming full-scale offensive operations at dawn.
  • Conduct raids, airborne landings, and the actions of FDs.

However, the OPFOR makes full use of the hours of darkness for major operational moves and for regrouping. It prefers to commit second echelons and OMGs at night, presumably on the calculation that surprise and the enemy's lack of balance offset the dangers involved.

Reinforcement of Success

Success in developing the offensive depends on--

  • The timely commitment of OMGs, second echelons, and/or reserves.
  • Shifting the army's axis of main effort to a different axis when resistance is too strong.
  • Consequently regrouping forces from less favorable axes.
  • The skill and initiative of subordinate commanders.

The underlying principle is the continual reinforcement of success and never of failure. Such a principle can actually help those formations that have run into trouble. The continuation of the advance can expose the flanks, rear, and lines of communication of a successfully defending or counterattacking enemy to attack. An army can shift its main effort to a new axis only on the instruction, or with the permission, of the army group commander. The resultant regrouping should be both rapid and secret, quite possibly with attacks being continued on the former axis as deception. Figure 5-17 depicts an army's shift of axis.

Figure 5-17. A tank army shifting its axis of main effort during a deep operation.


Extensive operational regrouping during the course of a strategic offensive operation is undesirable because it could lead to loss of momentum and confusion. Commanders should recognize, however, that some regrouping will probably have to take place. In any case, regrouping of armies within an army group or divisions within an army is not likely to occur more than once in a strategic operation, and then only if ordered or approved by the next higher commander.

Tactical regroupings within divisions and brigades, however, occur frequently, since the tactical situation can change often and radically. Another frequent occurrence is reorganization following the commitment of second echelons as the old first echelon becomes a new reserve.


In offensive operations following an initial nuclear strike, the basic forms of army operational maneuver in nuclear conditions would be attacks on multiple axes, encirclement, or the trapping of the enemy against a natural barrier.

In the event that nuclear use begins with only short warning and only one-third of systems permanently held ready to fire are available, initial strikes are usually concentrated on nuclear systems and command posts. As other weapons come on line, they target enemy troop groupings and logistics sites.

In a nuclear environment, penetration is not much of a problem and occurs speedily. However, enemy nuclear strikes affect the rate of advance. The time required to restore combat effectiveness to formations damaged in the initial exchange can be from 1 to 2 days or more.

In the advance, the problems of overcoming or bypassing areas of destruction, flooding, and/or contamination can slow movement. Consequently, it is likely that the average rate of advance may be much the same for both nuclear and conventional operations.

For planning purposes, the OPFOR should consider them to be identical, moving at an average of 40 to 60 km per day in mixed terrain and 30 to 50 km per day in mountains or marshy areas intersected by rivers. Thus, an army could still accomplish an operation extending to a depth of 250 to 350 km in 6 to 8 days.

Where the enemy has sustained decisive losses, the army can advance in prebattle or even march formation; mopping up requires only part of the army. Where both sides have taken massive casualties on more than one axis, or even across the entire zone of operations, there will almost certainly have to be a radical revision of the army's plan. It is imperative that the OPFOR move more quickly than the enemy in mounting attacks with elements that are still combat-capable and in delivering repeat strikes on enemy surviving forces and reserves.

Combat involves frequent meeting engagements, meeting battles, and extensive use of airborne landing, raiding, and forward detachments. The OPFOR bypasses strong enemy pockets where possible and concentrates its efforts on thrusting into the enemy's rear to destroy nuclear systems and to capture airfields. Second echelons or reserves destroy such bypassed groupings. Meanwhile, the OPFOR continues its efforts to locate and destroy enemy nuclear delivery means.

1 A corps could be composed of multiple separate brigades with no assisgned divisions.

2 This could still be the case, if the OPFOR employs infantry armies. See FM 100-63.

3 The use of precision weapons can greatly reduce ammunition expenditures required to support a penetration. If such munitions are available only in limited numbers, however, the OPFOR would normally concentrate them on the main attack axis.

4 On maps and diagrams, artillery groups often appear as "goose eggs" for the sake of convenience. However, this does not mean that all battalions assigned to a group locate physically in such a small area.

5 In this context, the term operational formation describes how an army (or army group) organizes and deploys its forces for combat. Thus it is the operational-level equivalent of the tactical term combat formation.

6 A corps forms a corps artillery group (CAG) to serve the same function, but on a smaller scale. It might comprise from 4 to 6 battalions and include the corps' organic MRL battalion. If the corps has two or more MRL battalions, it might form a corps rocket artillery group (CRAG).

7 See "Determining Factors" in Chapter 4 for details on the influence of terrain.

8 The zone of action is also sometimes called a zone of advance, attack zone, overall attack frontage, or sector or responsibility.

9 In mixed terrain, the OPFOR would expect to encounter--

  • A Stream 6 to 20 m wide every 20 km.
  • A stream 100 to 300 m wide every 100 to 150 km (the normal distance to an army's immediate mission).
  • A major water obstacle over 300 m wide every 250 tp 300 km (roughly the distance to an army's subsequent mission.)

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One Billion Americans: The Case for Thinking Bigger - by Matthew Yglesias