RPO or RRO will have a tag.

Counter is a weak-side run.

Blocking rules on Counter:

B: Cut off or ball carrier

Y: Skip Pull & follow BSG to 2nd level 

PST: Gap-Down-Backer

PSG: Gap-Down-Backer

Center: Gap-Down-Backer

BSG: Pull & Kick. If EMLOS squeezes, log him and Y will continue around you to 2nd level

BST: Pull check

T: Ball carrier, protecting B to C gap, or RPO tag

A: Crack to Safety unless RPO tag

X: Crack to Safety unless RPO tag