Pilón is the dance rhythm Enrique Bonne and Pacho Alonso launched from Santiago de Cuba in the early 1960s, named for the wooden mortar (pilón) used to pound coffee and grain — the dancers mime the pestle coming down.
How it sits: 2-3 son clave in the clave layer, but the feel is the opposite of a son tumbao: the pilón figure (kick, the big drum) strikes on beat 1 of every bar and rebounds on the and-of-2, and the bell marks quarters with the downbeat accented. The bass doubles it with a full tresillo — root on 1, fifth on the and-of-2, octave on 4 — instead of avoiding the downbeat. The conga keeps its ordinary open tones on 4 and the and-of-4, and the piano plays a light guajeo that anticipates the G7.
Listen for the weight on one: mute the drums and it sounds like any son; with them it thumps.
Practice: stamp the pilón strokes with your foot while clapping the clave; compare with guaracha, where the bass never plays beat 1.