Envelopment

Envelopment is the military tactic of seizing objectives in the enemy's rear with the goal of destroying specific enemy forces and denying them the ability to withdraw. Rather than attacking an enemy head-on as in a frontal assault an envelopment seeks to exploit the enemy's flanks, attacking them from multiple directions and avoiding where their defenses are strongest. A successful envelopment lessens the number of casualties suffered by the attacker while inducing a psychological shock on the defender and improving the chances to destroy them. An envelopment will consist of one or more enveloping forces, which attacks the enemy's flank(s), and a fixing force, which attacks the enemy's front and "fixes" them in place so that they cannot withdraw or shift their focus on the enveloping forces. While a successful tactic, there are risks involved with performing an envelopment. The enveloping force can become overextended and cut off from friendly forces by an enemy counterattack, or the enemy can counterattack against the fixing force.

According to the United States Army there exist four types of envelopment:

• A flanking maneuver or single envelopment consists of one enveloping force on a flank. attacking one of the enemy's flanks. This is extremely effective if the holding forces are in a well defensible spot (e.g. Alexander the Great's hammer and anvil at the Battle of Issus) or if there is a strong, hidden line behind a weak flank (e.g. Battle of Breitenfeld (1631) and Battle of Rocroi).
• A pincer movement or double envelopment consists of two simultaneous flanking maneuvers.Hannibal devised this strategy at this tactical masterpiece, Cannae Early in World War II the Germans frequently employed this tactic and encircled huge numbers of the enemy during the Blitzkrieg attacks on both the Western Front during the Battle of France and during Operation Barbarossa on the Eastern Front.
• An encirclement whereby the enemy is completely surrounded and isolated in a pocket. The friendly forces can choose to attack the pocket or invest it (to stop supplies getting and to prevent breakouts) and wait for a beleaguered enemy to surrender.
• A vertical envelopment is "a tactical maneuver in which troops, either air-dropped or air-landed, attack the rear and flanks of a force, in effect cutting off or encircling the force".