text: Chapter 2
  Figure 2-15. Penetration
  2-53. Supporting efforts focus on the remainder of the enemy forces in their current positions and isolate the
  objective from enemy forces. These operations prevent enemy forces from disengaging to reinforce enemy
  units opposing the main effort. Units track the battle’s progress to ensure that subordinate forces penetrate
  entirely through the enemy force’s main defensive positions and not just the enemy force’s disruption zone.
  2-54. Enemy forces normally try to slow down or stop a breach to gain time to react to the changing situation.
  The attacking unit must rapidly exploit and reinforce success. The attacker masses resources and additional
  units as necessary to ensure completing the penetration through the enemy force’s defensive positions.
  Widening the Gap to Secure the Penetration’s Flanks
  2-55. Once the attacking force penetrates the main defenses, it begins to widen the penetration of the enemy
  force’s defensive positions by conducting a series of shallow envelopments or attacks by fire. The task of
  widening the gap of the penetration is normally assigned to a follow-and-support force. Commanders also
  have the option of committing their reserve to accomplish that task. If the reserve is committed, the
  commander must designate another reserve, or the unit will not have the forces available to commit a reserve
  to another operation. Units plan to meet enemy counterattacks by shifting fires or committing reserves or
  follow and assume forces. They can use obstacles on the flanks of the penetration as a combat multiplier to
  assist in defeating any local enemy counterattacks and to maintain the force’s tempo.
  Seizing an Objective and Subsequent Exploitation
  2-56. The assault force attacks objectives to destroy the continuity of the enemy’s defensive position.
  Frequently, that objective is so far from the area of penetration that the unit or units initially conducting the
  penetration cannot seize it without pausing. In that event, units plan to commit the reserve or attack with the
  assault force through the breaching force early. Exploitation beyond the objective tends to be executed by
  divisions and corps. The exact force mix depends on the mission variables, while the armored, Stryker, and
  aviation forces are generally suited for subsequent exploitation.