text: Appendix C
  Hammer and Anvil Technique
  C-24. The hammer and anvil technique employs a stationary blocking force as an anvil on one or more sides
  of the inner perimeter, while other elements of the encircling force use offensive action as a hammer to force
  the encircled enemy force against the blocking force. Either the anvil or the hammer can destroy the enemy
  force. Usually the hammer, as the attacking element, accomplishes this task. This technique is most effective
  when the blocking force is located on or to the rear of a natural terrain obstacle. On favorable terrain, units
  can use an airborne or air assault force as the anvil or blocking element. Figure C-4 depicts the hammer
  technique.
  Figure C-4. Hammer technique
  Wedge Technique
  C-25. The wedge technique uses a unit to divide enemy forces in the pocket while the rest of the encircling
  force remains in place. This technique allows units to concentrate against a small portion of the encircled
  enemy force. However, the encircling force maintains pressure on other encircled enemy forces to prevent
  them from reinforcing or supporting the threatened area. The unit dividing the pocket conducts sudden and
  swift attacks immediately after the end of supporting preparation fires. Figure C-5 depicts the wedge
  technique.