An obsolete defensive formation in football comprised of seven down linemen, one linebacker and three safeties, with two close to the line and one farther downfield. Also known as the “seven diamond defense.”
The 7-1-2-1 defense, is a seven down linemen defense derived from the more traditional 7-2-2. This formation comes from an earlier time in football when seven-box defenses were mandated by football rules. The 7-1-2-1 defense was originally created to specifically stop Michigan back Willie Heston, and much like the 7-2-2, was incredibly vulnerable to the forward pass. The seven diamond defense also spaced linemen in a more compact formation opposite the offensive line, leaving the wings to be covered by the two wide safeties.
The 7-1-2-1 has seen some revival in recent years when used as a goal-line defense.