text: Movement and Forms of Maneuver
  2-46. Plans for penetrating a defensive position include isolating, suppressing, and destroying by fire enemy
  forces in an area selected for the penetration. These plans should also address how to isolate the area of
  penetration from support or reinforcement by enemy forces located outside the area. A critical part of a plan
  is positioning friendly assets so that units can mass the effects of their combat power to accomplish these
  results without giving away the location of the penetration.
  2-47. The majority of units and assets are in positions where the effects of their combat power apply to the
  area selected for penetration. Plans for the penetration normally have three phases:
  * Breaching the enemy force’s main defensive positions.
  * Widening the gap created to secure the penetration’s flanks.
  * Seizing an objective and subsequently exploiting the success of the penetration.
  2-48. Planning the sequence of these phases depends on the situation. In some situations, if there are
  weaknesses or gaps in an enemy force’s front, it is possible for armored forces to breach the enemy force’s
  defenses and proceed straight to an objective. Simultaneously, infantry units could conduct local
  envelopment and exploitation operations.
  2-49. Supporting efforts for outside the area of penetration are normally to isolate enemy forces on the flanks
  of the penetration. Synchronizing the effects of rotary- and fixed-wing aircraft, artillery fires, and obscuration
  to delay or disrupt repositioning forces are examples of supporting efforts. Units usually attempt to penetrate
  the enemy’s defensive positions along a boundary between two enemy units because defenses tend to be less
  effective along a boundary.
  2-50. Units plan penetrating through the enemy force’s defensive positions in enough depth so enemy forces
  cannot reestablish a viable defense in rearward positions. Units do not divert the strength of attacking forces
  to widening the gap to secure the flanks of the penetration until the forces achieve sufficient depth. However,
  plans should address contingencies, such as enemy counterattacks against the penetration’s flanks, if the unit
  culminates at any point during the operation or actions to take if the penetration is unsuccessful. Plans provide
  for uninterrupted support to attacking elements as they close with the enemy and accomplish their mission.
  Executing a Penetration
  2-51. After the initial breach of the enemy force’s defense, the situation determines the sequence of the
  remaining two phases. If enemy forces are in a weak position, it may be possible for the lead attacking force
  to seize the penetration’s final objective while simultaneously widening the initial breach. (See discussion
  beginning in paragraph 18-9 for more information on breaching.)
  Breaching the Enemy’s Main Defensive Positions
  2-52. The support force fixes the enemy along a broad front to allow the breach and assault forces to penetrate
  on a relatively narrow front. The support force can accomplish this by adjusting its lateral boundaries to the
  point or points of penetration or by extending its boundaries to fix the enemy on a broader front. This allows
  the force conducting the penetration to focus overwhelming combat power at that location. The support force
  locates where it can suppress the enemy for the breaching and the assaulting forces. The breach force
  establishes a lane or lanes to facilitate the assault force operation. The breach force can also be assigned near
  objectives to prepare the passing of the assault force. Figure 2-15 on page 2-18 depicts a penetration with
  two support forces fixing enemy forces on a broad front and the breach and assault forces executing the
  penetration.