Under salsa, son, and half of pop lies one five-stroke pattern — the CLAVE (Spanish for ‘key’). Everything in the band locks to it. It comes in two orientations, 3-2 and 2-3, which are just the same pattern started from its other half, and getting the orientation wrong makes a whole arrangement feel ‘turned around.’ Slide to flip 3-2 ↔ 2-3 and hear the key of the groove.
The son clave is a two-bar, sixteen-pulse rhythmic key: the 3-2 form places strokes on pulses 0, 3, 6, 10, 12 — three in the first bar, two in the second — and the 2-3 form is exactly the same pattern rotated by one bar (eight pulses). Five onsets across sixteen pulses make it nearly ‘maximally even’ (a Euclidean rhythm), which is why the identical stroke pattern anchors traditions from West Africa to Cuba to pop. Playing in the wrong orientation (‘crossed clave’) makes an arrangement feel turned around. A fail-loud self-check throws unless the clave has five onsets in sixteen pulses and 2-3 is a rotation of 3-2. ◆ real rhythm theory, node-verified.
The son clave (the rumba clave shifts one stroke); ‘rules the groove’ is the performance convention, and the maximally-even framing is the Euclidean-rhythm view — the five-in-sixteen pattern and the 3-2/2-3 rotation are exact.