How to play & controls Four-ball Billiards
Four-ball Billiards is a browser carom game built on the Korean four-ball format, with three-cushion and casual 8-ball on the same physics. Each player picks a personal target from 10 to 500 in steps of 10, so a beginner on 30 and a club player on 150 can play one game on even terms.
The table follows a 2540 × 1270 mm international carom table with 65.5 mm, 255 g balls. The cue ball slides before it rolls, side spin survives contact and changes the rebound off a cushion, and rails return less energy on hard hits. The same calculation runs the path guide, the server’s verdicts and the AI.
A failed shot gets a reason, down to how many millimetres the cue ball missed the second red by, and every contact is listed in order with its time.
Modes
Four-ball
Your white against the yellow, with two reds. Optional rules require 1–3 cue-ball cushions before the second red (Required cushions) or 1–2 before the first red (Rails before first red).
Three-cushion
White, yellow and one red. After the opening either object ball may come first; targets are set in points (1–50), and the opponent-ball foul and extra cushion rules are off.
Pool · 8-ball
Fifteen numbered 57.15 mm balls with the 8 racked in the centre, and six pockets on the same table size. Two players and no target, since the 8 decides the game.
AI Easy / Normal / Hard
You shoot the white and the AI the yellow, each with its own target. In carom games the level sets how fast the AI scores; in 8-ball, how far its aim strays.
Solo practice
The cue never passes and the game ends at your target. Retry this position restores the balls, the score and your last aim, spin and power.
Play online with friends
Signed-in players open a room for 1–4 and share a 4-character code or invite link. Four seats allow 2 vs 2 teams, except in 8-ball.
Billiards basics
A fixed layout with a 5–100% thickness slider, spin pad and 30/60/90% power presets that reads out the angles at which the white and red leave the contact.
Controls
| Action | Mouse & keyboard | Touch | Gamepad |
|---|---|---|---|
| Aim | Click or drag on the table; ←/→ 0.5° per press, Shift+←/→ 0.05°; ◀ ▶ buttons 0.1° | Tap or drag; ◀ ▶ for 0.1°; drag sideways in cue view | — |
| Power and shoot | Drag the right-hand gauge down and release; or ↑/↓ in 5% steps, then Space or Enter | Pull the gauge down and let go; slide back to the top to cancel | — |
| Spin | W/A/S/D, read by key position; or the ball icon at bottom left | Tap the ball icon, then tap or drag on the spin pad | — |
| Stroke | Normal, Snap or Push in the spin panel | Same buttons | — |
| Camera | V, or the Cue view / Table view button | Cue view / Table view button | — |
| Ball in hand (8-ball) | Click an empty spot clear of balls and pockets | Tap an empty spot | — |
| Review | Skip ▸▸, Replay last shot, or click a timeline row | Same buttons; tap a timeline row | — |
Strategy tips
Your target decides whether the yellow is in play
The opponent-ball foul applies only when the shooter’s own target is above 30 and the option is on (the default). Only your cue ball’s contacts count: a red knocked into the yellow is fine, but your cue ball touching it is a foul even after both reds.
The guide stops at the first contact
The path guide shows the cue ball up to its first contact, a ring where it touches, then only 0.7 seconds of both balls’ paths, so the second red is yours to plan. In four-ball, a yellow rather than pink dashed line on the struck ball means you are about to hit the opponent’s ball first.
Power is not linear
Speed follows the gauge to the power of 1.35: 50% gives about 2.2 m/s, 42% of the 5.2 m/s maximum. Rails also soak up hard hits, the rebound coefficient falling from 0.9 on slow contacts to 0.74 at about 4.2 m/s, so full power adds fewer cushions than expected.
Pair the stroke with the spin
Snap adds 5% speed and keeps 22% more draw but only 85% of the follow. Push loses 4% speed and keeps 18% more follow but only 85% of the draw. Use Snap with bottom spin and Push with top spin, as the AI does.
Side spin acts at the rail
Side spin does not curve the ball on the cloth. It changes the rebound when the ball meets a cushion, right spin sending it off to your right, and slightly throws the object ball at contact. A centre-ball, half-ball hit splits the two balls at about 90°.
Beat the AI’s schedule, not its aim
In the carom games the AI plans to finish in about 30 innings on Normal, 43 on Easy and 21 on Hard, hurrying when behind and easing off when ahead. Its target barely changes that schedule, so on Normal you need to average your target ÷ 30 scores per turn: one every three turns at 100.
8-ball: clear your group before the 8
The 8 wins only if your group was already empty before that shot, so sinking your last group ball and the 8 together loses. After the break, the first group ball to drop on a legal shot sets the groups. The AI takes ball in hand on the white’s starting spot or the nearest free one.
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