Diamond system — Aim = Arrival − Start
A second three-cushion calculation, as backup to the Conti system
Bottom cushion: start and arrival, from 0 to 7 from the right corner, confirmed domain (2 to 7) in gold. Right cushion: the aim, fixed scale from 0 (corner) to 4 (middle). Left cushion: the arrival continued beyond 7, from 8 (corner) to 11 (middle).
The formula
Aim = Arrival − Start
The start and the arrival are read on the bottom cushion (or the left cushion if the arrival goes past the 7th diamond). The aim is read on the right cushion, a fixed scale that's always the same.
The reference marks
- Start: the position of ball 1 on the bottom cushion, from the right corner, 0 to 7. Confirmed here for a start of 2 to 7 diamonds.
- Arrival: on the same bottom cushion if it's 7 or less; beyond that, it continues on the left cushion, from 8 (corner) to 11 (middle).
- Aim: the result of the subtraction, on the right cushion, from 0 (corner) to 4 (middle) — fixed, whatever the start.
Five examples, from the tightest to the widest
| Start | Arrival | Aim |
|---|---|---|
| 2 | 3 | 3 − 2 = 1 |
| 5 | 7 | 7 − 5 = 2 |
| 3 | 6 | 6 − 3 = 3 |
| 6 | 9 | 9 − 6 = 3 |
| 7 | 11 | 11 − 7 = 4 |
The cue stroke, always the same
- Ball struck in the center, at center height.
- 2 tips of good side spin, always the same.
- Cue held as horizontal as possible.
- You aim right at the heart of the diamond.
- A measured stroke, neither pushed nor held back.
When to use it
As backup to the Conti system, when a ball happens to block the aim line the Conti system would need. Same logic — a start, an arrival, a subtraction — with different reference marks.