“On1” Salsa Dancing
The man (leader) steps forward on beat #1 and back on beat #5. This is reversed for the lady (follower). The pause happens on beats #4 and #8. This is probably the most widespread style worldwide. It is characteristic of the Colombian, LA and contemporary Cuban styles.

“On2” Salsa Dancing
The man (leader) steps back on beat #2 and forward on beat #6 (as usual, this is opposite for the lady). Why this is reversed has to do with the different underlying philosophy of the relationship between male and female partners in the dance, and is only indirectly related to music rhythm. It is characteristic of New York and Puerto Rico styles.