Son clave

The key pattern of Cuban son, salsa and most Afro-Cuban music: a tresillo (the "3 side") answered by two on-beat hits (the "2 side"). Everything else in the band lines up with it. Notated here as one bar of cut time; in a 4/4 chart it spans two bars (3-2 as written, 2-3 when the two-side comes first). The 3 side is pulled off the beat, the 2 side sits on beats 2 and 3, and the gap on beat 4 of the two-side is where the bass and piano anticipations fall.