text: Chapter 6
  6-48. Usually, there is some warning of an enemy attack. The enemy must be brought under the maximum
  mass of counter preparation fire as early as possible. Counterpreparation fire is the intensive prearranged
  fire delivered when the imminence of the enemy attack is discovered. Counterpreparation fire disrupts
  the enemy's preparations for an attack or a counterattack. It does this by striking him in his assembly areas;
  breaking up his attack formations; disorganizing his command, control, and communications; impairing his
  TA capabilities; and reducing his morale. Counterpreparations are usually scheduled as on call. The
  counterpreparation may be phased, although this is not required.
  * Phase 1 includes: enemy forward elements, indirect fire systems, observation posts.
  * Phase 2 includes enemy CPs, communication and reserves while attacking of indirect fire systems
  continues.
  6-49. During an area defense, FS assists in shaping operations that constrain the enemy into a specific COA
  or fix them in a given location. These actions limit the enemy's options. The supported commander covers
  obstacles with fires that turn, or block to limit the options available to the enemy. The main effort focuses
  fires into EAs, possibly supplemented by a counterattack. The supported commander directs reconnaissance,
  surveillance, and TA WLR assets to determine the locations, strengths and probable intentions of the
  attacking enemy force. Specific FS considerations include:
  * Providing long-range shaping fires to delay, disrupt, and attrit enemy forces.
  * Provide fires for spoiling and counter attacks.
  * Positioning firing units forward to support a covering force to include SOF operating in zone.
  * Ensure FSCMs, CFZs and CFFZs are established.
  * Engaging enemy long-range indirect fire systems prior to the enemy executing preparation fires.
  * Massing fires to break the momentum of an enemy attack.
  * Providing counterfire support to divisions and BCTs as the enemy enters the EAs allowing the
  BCT's organic FA BNs to execute close support fires for maneuver.
  * Providing fires to disrupt follow-on echelons.
  * Ensuring FS for the battle handover and withdrawal of the security forces.
  MOBILE DEFENSE
  6-50. The mobile defense is a defensive operation that concentrates on the destruction or defeat of the enemy
  through a decisive attack by a striking force (ADP 3-90). In a mobile defense, commanders take advantage
  of terrain in depth, military deception, obstacles and mines while employing fires and maneuver to seize
  initiative from the attacking enemy force. The commander weights the striking force, with the allocation of
  FA and other FS resources available.
  6-51. The defending force's planned maneuver must incorporate the movement of FS assets to locations
  where they can provide continuous support. FS assets enhance the supported force combat capabilities and
  enable the quick defeat of the enemy force.
  6-52. The defending commander takes precautions to prevent fratricide by establishing a restrictive fire line
  (RFL) and other FSCMs. The commander positions FS assets to support screen and guard forces and allocates
  additional artillery to support a covering force. If the security force is assigned a large OA, the commander
  may have to position FS assets to provide effective coverage of only the most likely enemy avenues of
  approach. This is particularly important for a screen because often the screen force relies on indirect fire to
  delay or disrupt the enemy. Providing adequate indirect FS to the security force may require the main body
  to position its artillery well forward in its formation. Other FS considerations for a mobile defense include:
  * Weight the striking force with the most flexible FS attack/delivery platforms available such as
  CAS and attack aviation.
  * Positioning two-thirds of the available firing units with the striking force during a mobile defense
  and one- third with the fixing force.
  * Planning for frequent survivability moves of TA WLR assets based on movement of the FLOT.
  * Planning for the use of obscuration or screening smoke to support both the fixing and striking
  force.
  * Positioning ammunition stocks for each phase of the operation.