Running and reverse english
Sidespin, english, changes what a cushion does to the ball. Turned with the ball's travel it helps; turned against it, it fights. That difference is one of the clearest rules of shot selection: prefer running english.
What each one does
When a spinning ball meets a cushion, the cushion grips the spin. Whether the spin helps or hurts depends on which way it turns compared with the way the ball is travelling along the cushion.
| Running english | Reverse english | |
|---|---|---|
| Spin turns | with the ball's travel along the cushion | against it |
| Angle off the cushion | wider (longer) | narrower (shorter) |
| Speed | kept | taken off |
| Change with speed | small | large |
Why running english is easier
With running english the cushion and the spin work together, and the rebound is much the same at a soft pace as at a firm one. Your eye and your memory of the angles stay valid. Reverse english changes the angle a lot, and how much depends on speed: hit a little harder or softer and the ball comes off somewhere else. Every reverse cushion is an extra error you have to judge.
That's why the natural, running english around the table, is the first shot to look for.
When reverse is worth it
There's one place reverse english earns its keep: the last cushion into a big ball. If the second ball sits near a rail, a little reverse on the final cushion can bring the cue ball in along that rail, so it meets the ball from the cushion side where the target is widest. The error that reverse adds is small on the last cushion, because there's little distance left for it to grow, and the bigger target more than pays for it.
Reverse on the first or second cushion of a long route is the opposite: the error has the whole table to grow. Avoid it unless there's truly nothing else.