text: Mobile Defense
  necessary to commit the striking force. The striking force commander requires timely updates of the enemy
  situation to ensure that the striking force engages the enemy force at the right location and time.
  10-27. While conducting delaying tasks, the security force determines what routes the enemy force is using,
  where the enemy force is strong or weak, and where gaps exist within enemy formations. This information
  aids units in seizing the initiative by identifying opportunities. Further, it helps direct the striking force along
  the path of least resistance, as it maneuvers to employ its combat power at the critical time and place.
  FIX THE ENEMY
  10-28. In a mobile defense, units conduct supporting efforts to disrupt the enemy force’s commitment of
  reserves and follow-on echelons into the battle. These supporting efforts create the conditions for committing
  the striking force by isolating the object of the striking force and destroying the enemy force’s key command
  and control nodes, logistics resupply units, and reserves. Whenever possible, units sequence these supporting
  efforts, including the use of electromagnetic warfare, so that their effects coincide with the commitment of
  the striking force. To generate a tempo that temporarily paralyzes enemy C2, units increase the intensity of
  these supporting efforts on the commitment of the striking force. Units continue to conduct supporting efforts
  once the striking force commits to prevent enemy forces outside the objective area from interfering with the
  decisive counterattack.
  10-29. Fixing the enemy force establishes conditions necessary for the main effort by the striking force.
  Typically, commanders of the defending force allow the enemy force to penetrate the MBA before the
  striking force attacks as shown in figure 10-4 on page 10-8. The fixing force may employ a combination of
  area defense, delay, and strong point techniques to shape the enemy penetration. The intent of the fixing force
  is not necessarily to defeat the enemy force but to shape the penetration of the enemy force to facilitate a
  decisive counterattack by the striking force. Commanders ensure that the missions and task organization of
  subordinate units within the fixing force are consistent with the concept for preventing the enemy penetration.
  Defensive positions within the fixing force may not be contiguous since the fixing force contains only the
  minimum-essential combat power to accomplish its mission.
  10-30. In a mobile defense, units retain ground only to facilitate the commitment of the striking force. Units
  can yield ground to make the enemy commander think that their attack is successful or to entice the enemy
  to move to a point where the striking force can attack. The fixing force’s use of obstacles supports this shaping
  effort and helps it gain a mobility advantage over enemy forces.
  10-31. During a mobile defense, commanders may need to commit the reserve to reinforce the fixing force
  and help shape the battlefield. They position their reserves so they can effectively react to the enemy force’s
  most likely and most dangerous course of action. Without a reserve, commanders assume significant risk in
  attempting to shape enemy penetrations. Circumstances may also force them to employ elements of the
  striking force to assist the fixing force. If that occurs, units can use available long-range fire support assets
  and attack helicopters. These assets allow them to rapidly disengage and shift support during the striking
  force’s commitment.