Game guide · Carom billiards
Straight rail: the foundation of every controlled carom.
A point is scored when your cue ball contacts both other balls. The rule is simple; the real game is controlling the position you leave behind.
- 2.30 × 1.15 m
- Carambole small table
- 61 mm
- Three carom balls
- One carom
- One point
- 25 points
- Default game distance
Objective and turn order
You play with your own white or yellow cue ball, your opponent's cue ball and the red object ball. A carom is complete when your cue ball contacts both other balls during one stroke. The order is free and cushion contact is optional.
Every legal carom scores one point and keeps you at the table. If you fail to contact both object balls, your run ends. Straight rail therefore rewards more than making contact: the strongest stroke also leaves an easy and controllable next position.
- Contact both object balls with your cue ball.
- A direct path or a path using one or more cushions is legal.
- A legal carom scores one point and lets you continue.
- A miss or rule violation ends the turn.
Table, balls and opening position
Carambole uses a 2.30 × 1.15 metre small-table profile for straight rail. The international UMB match table measures 2.84 × 1.42 metres. Both have an exact two-to-one playing-surface ratio, but the longer match-table routes require noticeably more speed.
The simulator uses three 61 millimetre carom balls. They are larger than pool and snooker balls and the table has no pockets. At the opening position, or acquit, Carambole places all three balls on fixed spots. The opening player must contact the red ball first.
| Item | Carambole | Competition reference |
|---|---|---|
| Playing surface | 2.30 × 1.15 m | UMB match table 2.84 × 1.42 m |
| Balls | White, yellow and red | Three approved carom balls |
| Ball diameter | 61 mm | Approximately 61–61.5 mm in federation specifications |
| Pockets | None | None |
Why the corner zones exist
On the small straight-rail table, each corner is marked by a diagonal line. If both object balls remain in the same corner zone, scoring cannot continue there indefinitely. After one carom in the same zone, at least one object ball must leave that zone on the next legal carom. It may return during the same stroke.
This prevents a player from locking the balls in a corner without meaningful movement. Carambole uses triangular zones with 17-centimetre legs and tracks whether both object balls remained together inside one zone.
Scoring and winning
A match is played to a predetermined distance. In Carambole's standard straight-rail mode, the first player to 25 caroms wins. Club and federation distances vary by class and competition.
Some competitions allow an equalizing inning when the opening player reaches the distance first. Carambole's standard match ends when a player reaches the selected target. This guide therefore distinguishes the general sport from the simulator's concrete match settings.
Common mistakes
For a beginner, a clean and quiet stroke with little side spin is usually the best control tool. Learn contact thickness and speed first; spin is a deliberate correction, not a replacement for a sound line.
- Only one object ball is contacted: no point and the turn ends.
- The opening stroke fails to contact red first.
- Both object balls remain too long in the same corner zone.
- The player makes the current carom but sends all three balls far apart.
- Excessive side spin makes speed and arrival harder to predict.
How Carambole implements straight rail
The simulator uses the small table, three 61 mm balls, the opening position, red-first opening rule and 17 cm corner zones. Every legal carom scores one point and the default match distance is 25.
For the transition from isolated points to a run, continue with the Straight Rail Lesson. It covers contact thickness, draw, follow, gathering, return shots and the rail nurse.
Sources and verification
Content last verified on 8 August 2026. In official competition, the current governing rulebook takes precedence.
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