text: _________________________________________________________________________________Chapter 4
  4-105. The distance between successive positions in the disruption zone is
  such that the enemy is forced to displace the majority of his supporting weap-
  ons to continue the attack on the subsequent positions. This aids the force in
  breaking contact and permits time to occupy subsequent positions. Long-
  range fires, ODs, and ambushes to delay pursuing enemy units can assist
  units in breaking contact and withdrawing.
  4-106. If the disruption force has not succeeded in destroying or halting
  the attacking enemy, but is not under too great a pressure from a pursuing
  enemy, it may occupy prepared battle positions in the battle zone and assist
  in the remainder of the defensive mission as part of the main defense
  force. A disruption force may have taken losses and might not be at full
  capability; a heavily damaged disruption force may pass into hide positions.
  In that case, main defense or reserve forces occupy positions to cover the dis-
  ruption force’s disengagement.
  Main Defense Force
  4-107. The mission of the main defense force is complete the defeat of the enemy
  by attack of those portions of the force exposed by disruption zone operations.
  In a multi-OSC operation, this may involve resubordination of units and in some
  cases attacks by fire or maneuver forces across OSC limits of responsibility.
  4-108. The main defense force in a maneuver defense divides its combat
  power into contact and shielding forces. These forces move in bounds to
  successive defensive lines. If maneuver defense in the disruption zone has
  provided sufficient time, the defensive positions on these lines may take on
  more of the characteristics of prepared battle positions.
  4-109. The basic elements of the battle zone are battle positions, firing lines,
  and repositioning routes. Battle positions use the terrain to protect forces
  while providing advantage in engagements.
  4-110. The commander may order a particular unit to stand and fight on a
  line long enough to repel an attack. He may order this if circumstances are
  favorable for defeating the enemy at that line. The unit also might have to
  remain on that line because the next line is still being prepared or a vertical
  envelopment threatens the next line or the route to it.
  Reserves
  4-111. An operational-level command in the maneuver defense can employ a
  number of reserve forces of varying strengths. The maneuver reserve is a
  force strong enough to respond to unforeseen opportunities and contingencies
  at the operational level. It is normally strong enough to defeat the enemy’s
  exploitation force. The commander positions this reserve in an assembly area
  using C3D to protect it from observation and attack. From this position, it
  can transition to a situational defense or conduct a counterattack. The re-
  serve must have sufficient air defense coverage to allow maneuver. If the
  commander does not commit the reserve from its original assembly area, it
  maneuvers to another assembly area, possibly on a different axis, where it
  prepares for other contingencies. (See the Reserves section above for discussion
  of other types of reserves.)