Watch
A rolling cue ball, half-ball hit: aim along this line.
Why it matters
A rolling cue ball does not leave along the tangent line. It curves forward. This works for most cuts, from a quarter-ball to a three-quarter-ball hit. The cue ball ends up close to 30° from the line it came in on. Rolling shots are very common, so this rule helps you see where the cue ball goes on many of them.
How to do it
- 1
Use it on rolling shots: medium speed, a little above centre on the cue ball.
- 2
Find the aiming line from the cue ball to the ghost ball.
- 3
Make a V with your first two fingers, like a peace sign. That is about 30°. Point one finger along the aiming line, with the V at the ghost ball.
- 4
The other finger shows where the cue ball goes.
Common mistake
Using it on stun or draw shots
The 30° rule only works when the cue ball is rolling at contact. A stunned cue ball goes along the tangent line, at 90° to the object ball’s path. Draw pulls it back past that line. Check how you will hit before you use the rule.
Try it tonight
Exercise · Advanced
Rolling half-ball cut
Object ball one diamond out from the end cushion and one diamond out from the long cushion, near a foot corner pocket. Cue ball level with the first diamond past the side pocket, about 1½ diamonds out from that same long cushion (about a 30° cut). Hit at medium speed, a little above centre. Before each shot, point your fingers in a V to see where the cue ball will go. After each shot, check if the cue ball ended up on that line. Every attempt counts.
- Pass: 4 of your last 5
- Then: A fuller cut