Number 1-5 from R to L
U= Team A players 4 & 5 from his sideline
SJ= Team A players 2 & 3 on his side.
Number 1-5 from L to R
FJ= Team A players 2 & 3 on his side
BJ= Team A players 4 & 5 on his side
Chart says Player 1 (outside nerest sideline) is not accounted for in the keys because he normally isn't threatened until he reaches the wing's zone.