The six-stroke roll is six notes — R L L R R L — a single-double-double-single shape: a single, then a double in the opposite hand, then a double back in the original hand, then a single in the opposite hand again. In 6/8 it lays out cleanly as one rep per bar with the two doubles straddling the middle of the bar.
The traditional accent pattern accents notes 1 and 4 — the lone leading R, and the first R of the closing RR. Those are the two natural waves of the rudiment: a single-led wave into the LL diddle, then a double-led wave into the closing L. Two crests per bar in 6/8 phrasing.
Six notes per group is what makes this rudiment fit the triplet/compound family along with the double paradiddle and paradiddle-diddle. The texture distinguishes it from those neighbors: where the double paradiddle is single-heavy (four singles, one double) and the paradiddle-diddle splits the difference (two singles, two doubles), the six-stroke is double-heavy (one single, two doubles, one single) — the chunkiest of the three.
This lesson teaches the rudiment: the snare-only shape and its accent options. The kit application — moving the doubles to toms, terminating phrases with a crash — lives in the fusion-six-stroke-roll lesson once this one is under your hands.