If salsa has a single secret, it is the clave. Five strokes spread across two bars of music, it is the rhythmic key that everything else in the band locks onto — and most dancers move for years without ever consciously hearing it. Learning to feel it is one of those changes you cannot undo.
The clave comes in two directions, usually described as 3-2 or 2-3 depending on which half of the pattern lands first. The three-side has a syncopated, leaning-forward feel; the two-side answers it with a steadier pair of strokes. The whole band — piano, bass, horns, congas — arranges itself around this pattern, whether or not the claves themselves are actually being played.
For a dancer, the clave is less a thing to step on than a thing to feel underneath. You do not usually break on the clave; you use it as the grid that tells you where the music's tension and release live. Dancers who feel it tend to pause in the right places and accelerate in the right places without thinking about it, because they are riding the same structure the musicians are.
The way in is repetition and attention. Put on a track, find the clave, and clap it until you lose it, then find it again. Do that for a few weeks and something clicks: it stops being a puzzle you solve each time and becomes a pulse you simply hear, the way you hear the beat.
After that, the music is never flat again. A song reveals its architecture — where it is winding up, where it is about to break open — and your dancing starts to answer the music instead of just occupying it. Five strokes. That is all it takes.