When identifying the players for whom the Quarterback, Playside A, and Playside Receiver are responsible to cancel, utilize the following:
#1 (Read Key)- Defender touching the Tackle. He is cancelled by the Quarterback.
#2 (Pitch Key)- Defender on or past #1. He is cancelled by the Quarterback.
#3 (Run Support)- Defender on or past #2. He is cancelled by the Playside A.
Deep Defender- Defender who drops over the top of the Receiver when the Receiver sprints off the football. He is not part of the count. He is cancelled by the Receiver.
Here are examples of the count system as it corresponds to common defensive alignments.