The opening is a repeatable position, not a free placement anywhere behind a line. Learn which parts the rules fix before choosing the cut, spin and pace. This guide uses UMB carom rules; a PBA event can prescribe a different opening.
Separate the lag from the opening
In the UMB rules, the lag winner chooses who starts. The lag positions are not the starting position for the scoring stroke. For that stroke, the referee puts red on the top spot and the other player's ball on the bottom spot. The starter uses white, choosing one of the two starting spots beside the bottom spot.
The first contact must be directly with red. You cannot choose yellow first or play a cushion before red just because that route looks easier. The two permitted cue-ball spots offer a choice of side, not unrestricted ball in hand.
Count the contacts that actually matter
For a three-cushion point, the cue ball must touch both object balls and make at least three cushion contacts before touching the second object ball. These can involve the same cushion more than once. Count cue-ball contacts, not red's rebounds. Red → cushion → cushion → cushion → yellow is one valid sequence if no other foul occurs.
Reaching yellow after only two cushion contacts does not become a point when white later reaches another cushion. Nor must an opening score use exactly three contacts: a longer legal route is possible. Wait for the balls to stop before judging the completed stroke or shooting again.
Build a reference, not a magic aim
Choose one starting side and keep it fixed. First check red contact thickness; then record the first and third cushion arrivals and the side on which white misses yellow. Include red's movement: a returning red can interrupt the intended route. Do not solve a collision problem solely by moving the final aiming target.
Practice the other starting side as a separate layout. A mirrored drawing is a useful geometric comparison, but cushion response, access and your stroke may differ. Neither a fixed tip offset nor a universal diamond target guarantees the opening on every table.
Compare one change at a time
Make a short baseline series, reset all three balls after each attempt, and write down cut, spin, pace and result. For a second series alter only one input. If the first-cushion arrival already changes, investigate the initial line and red contact before trying to correct the third cushion.
Distinguish three failures: wrong contact sequence, a correct sequence that passes yellow, and an extra collision that changes the route. Also record the final layout after a point. This makes the exercise useful for both the opening and the next shot; a single successful attempt does not establish a reliable percentage.
Use the simulator and event rules for different purposes
The 3Ball opening preset below shows the app's actual coordinates on a 284 × 142 cm table. It is an editable practice layout, not evidence that the app referees every tournament condition. Inspect the replay yourself and check the reference on your physical table.
The cited UMB text is the edition effective in 1989, Articles 22–24 and 83. Check the current event regulations as well, particularly for equalizing innings. PBA's 2026–27 guide uses its own opening arrangements; do not transfer a UMB setup to that circuit without checking the stage.
Open the actual practice position
This diagram uses the app inventory, not an independently measured competition table. No solved trajectory is shown.
Opening (tournament)
White 71 × 52.75 cm · Yellow 71 × 71 cm · Red 213 × 71 cm
Open this layout →