Defensive line techniques

The language coaches use to describe every alignment: 0 = head-up on the center; 1 = center’s shoulder; 2i/2 = guard’s inside shoulder / head-up on the guard; 3 = guard’s outside shoulder (B-gap); 4i/4 = tackle’s inside shoulder / head-up; 5 = tackle’s outside shoulder (C-gap); 6/7 = on the tight end’s inside/outside shoulder; 8–9 = outside the tight end (9 = the Wide 9). Even numbers are head-up, odd numbers are outside shades, ‘i’ is an inside shade.

Reference — once you know the numbers, every front above reads like a formula.