Flying wedge

This V-shaped arrangement began as a successful military strategy in ancient times when infantry units would move forward in wedge formations to smash through an enemy's lines.

This principle was later used by Medieval European armies, as well as modern armed forces, which have adapted the V-shaped wedge for armored assault.

In modern times the effectiveness of flying wedge means it is still employed by civilian police services for riot control.

The wedge (ἔμβολον, embolon in Greek; cuneus in Latin, colloquially also caput porcinum, "boar's head"), was used by both infantry and cavalry.

According to the Roman historian Tacitus, the Keil was a tightly packed crowd, strong on all sides, not only in front and back, but also on the flanks.

The goal was to hit hard at the same time and to drive a 40 yard wide hole into the enemy line, according to the German historian Hans Delbrück.

[3] According to Richard Burton, the central body consisted of heavily armed, warriors protecting less-armored archers to the sides.

[5][6] The tactic was a formidable assault strategy against defenders in line or column, however, attackers faced annihilation in the event of retreat because the wedge became an ill-defined mob if its forward momentum collapsed.

Armored, heavily armed infantry could use their momentum in wedge formation to drive open small sections in the shield wall.

[11] Sir Charles Oman refers to an unpublished manual of 1480 by Philip of Seldeneck[12] which describes the formation, calling it the Spitz.

Exactly the same principles of mutually supporting lines of sight and fire, apply to an armored vehicles deployed in a wedge formation.

[17] The principle is similar to the military application: the ball carrier starts an attack and is joined on both sides by teammates who drive them forward, toward the goal line.

However, due to the number of deaths and serious injuries related to the flying wedge, any attempt at this formation is now punished by in-game penalties.

[18] The penalty against assisting the runner, which forbids the locking together of players as well as pushing and pulling the ball carrier to increase force in the same manner as the historic flying wedge, remains in the American football rule books; its eradication has been so complete that the foul has not been called in the National Football League since 1991.

[19] The concept of wedge-shaped formations continued to influence several football plays in the modern game, particularly on kickoff returns, until 2009 when NFL league owners agreed to stop its use.

[17] Recent changes in the rules at various levels regarding runbacks of free kicks are stricter still in that they restrict blocking by teammates close together even without touching each other.

The "wedge" commonly referred to in interference on free kick returns simply meant such a close group of blockers.