One note per stroke, and the arm changing plane between every one. There is no slurring to hide behind here, so this is where the bow arm's real state shows: a crossing that arrives late puts a gap in the line, and a crossing that arrives early clips the note before it.
The partition
The pattern declares one thing: its repeating group-length cycle, 1, starting on a down bow. Over eight notes that produces exactly this, and the directions alternate by construction — a boundary the bow did not reverse at would not be a boundary:
| Stroke | Notes | Length | Direction |
|---|---|---|---|
| 1 | 1 | 1 | down |
| 2 | 2 | 1 | up |
| 3 | 3 | 1 | down |
| 4 | 4 | 1 | up |
| 5 | 5 | 1 | down |
| 6 | 6 | 1 | up |
| 7 | 7 | 1 | down |
| 8 | 8 | 1 | up |
4 of 8 strokes start on a beat when the eight notes are eighth notes in common time. That number is the pattern's character: strokes landing off the beat are what a listener hears as lift.
Which crossings are real
A bow can lean between two NEIGHBOURING strings; anything further apart needs a jump, not a crossing. Derived from the instrument's true open pitches, the real pairs are G–D, D–A, A–E, each a 7-semitone interval. CI checks every crossing this site publishes against that list, so a page can never suggest one the arm cannot make.
Practising it
Put it on an open string first, with the left hand doing nothing at all. The pattern is a right-arm skill and mixing it with a fingering problem just hides which one is failing. Once it is automatic, run it over a scale, and only then over a tune.
Watch the bow rather than the fingers. Every note in a group shares one stroke, so the length of a group is a distance along the hair — an even partition needs even distribution, not just even timing.