How it works
The same three numbers and the same subtraction. The one difference: the ball is read one rail further on — the arrival is on the fourth rail, not the third.
The path is unchanged: far long rail (1), short rail (2), near long rail (3), then on towards the fourth rail. Follow the arrows on the diagram — the arrival is the number where that last leg meets the fourth rail.
Fourth-rail numbers: 40 in the top corner, then 52, 64 and 76 a diamond apart going down. Start 70 to arrive at 52: aim at 18.
Three tips of running side instead of two — a longer path needs more side to hold its line — at the same medium speed.
Reading the numbers
Start Where the cue ball's line, as it leaves the red, runs back to the near rails. On the short rail behind the cue ball it reads 50 in the corner, 60 and 70 at the first two diamonds, then 80, 90 and 100 at 2½, 3 and 3½ — the numbers close up towards the middle of the rail. On the long rail, from the same corner, it reads 5 a diamond down to 20: 45, 40, 35 … 20.
Aim On the first cushion, the far long rail: 0 at the far corner, 10 a diamond back to 50 at the third diamond, then 10 every half diamond up to 100.
Arrival On the fourth rail, the short rail the ball is heading for after the third cushion: 40 in the top corner, then 12 more every diamond down — 52, 64, 76. The second ball waits just in front of it, so read where the line the cue ball is travelling on reaches the rail, not where the ball ends up.
Step by step
- Choose the arrival: where on the fourth rail the cue ball's line must land to make the second object ball, which waits just in front of that rail.
- Read the start from the line the cue ball leaves the red on, traced back to the short rail — or to the long rail when it comes from below the corner.
- Aim = Start − Arrival. Start 70 to arrive at 52 aims at 18.
- The new aim moves the line, so re-read the start and work it once more. Then add the table correction.
The stroke
Three tips of running side, medium speed, a touch of follow, level cue. A tip fewer moves the fourth-rail finish about a quarter of a diamond and makes it less predictable.