What it is

A counter is a running play that begins by moving in one direction and then hands the ball off in the other. Linemen usually pull across the formation to block.

In a game

The defense reads the first step of the offensive line and the backs and moves with them. When the ball goes the other way, the defenders are out of place and the pulling blockers meet the pursuit.

More detail

The play is timing-based. The quarterback must make the false step convincingly and the pulling guard has to find the right defender. It is an old trick that stays effective because defenses are trained to pursue aggressively.

Animated diagram

1. The backs and the quarterback first move to the right, as if the play were going that way.
2. The defense follows them. At the same time, a guard pulls across the formation to the left.
3. The quarterback hands off to the back, who runs left behind the pulling guard.