How to Play Backgammon

Your checkers travel round the twenty-four points like a horseshoe, into your home board — the last six points. Each game opens with both players rolling one die: the higher goes first, with those two numbers. Turn on Show pip counts (Settings) to see how far each side still has to go — the race at a glance.

Tap your dice to roll (and the cube, before you roll, to double), then move one checker for each die: tap a checker (anywhere on its point) and it moves by the lit die — the higher one, or tap the other die to light it first. Tap it again to move it on by the other die; bearing off is a tap too. Or drag a checker where you want it, or just tap a point when only one checker can get there. Doubles play four times. You must use both dice if you can. Undo takes a checker back; Done ends your turn. A roll that can only be played one way plays itself (“Forced move”). As on a real board, nothing shows you where you can go. Learning? Turn on Show available moves in Settings: the checkers that can move wear a ring, and the places the picked one can go glow.

A point with two or more of your checkers is yours — nothing can land there. A single checker is a blot: land on it and it’s hit, sent to the bar in the middle. A checker on the bar must come back in, on the far side of the board, before anything else of that player’s can move.

Once all fifteen of your checkers are in your home board, you can bear off: a die takes a checker off from the point it names, or the highest one if nothing’s further back. Get hit meanwhile and you have to come all the way home again first.

Before you roll, you can Double the stakes. Your opponent takes — the game is worth twice as much and the cube is theirs to turn next — or passes and loses the game at the old stakes. Turn on Roll for me when I can’t double for a quicker game when the cube isn’t yours to turn.

A game is worth a point times the cube: two for a gammon (the loser bore nothing off), three for a backgammon (and still has a checker on the bar or in the winner’s home board). Play one game, or first to 3, 5 or 7 points. The game after someone first reaches one point short of the match is the Crawford game: no doubling.

Five regulars, from beginner to world class: Pippa, Uncle Theo, Lucky Luca, The Professor, The Champion. Hint shows the best play against them. Or play a friend: send a link from the room, and every match goes on your record against them (no hints with a friend). Resign the match from Settings.

Every match you finish moves your rating — the FIBS formula, the one backgammon players have kept for decades. Everyone starts at 1500. Beat someone rated above you and you gain more; lose to someone below and you drop more. The match’s length counts too: a long match is less of a lottery, so the stronger player is more of a favorite, and it moves your rating further. The regulars are rated as well (the Champion is 1670), and the lobby shows what a win or a loss would do before you start. A friend’s match counts against their rating.

When a match ends, the engine reviews every decision you made — each play, each double, take and pass — against the best there was. Your Performance Rating (PR) is the equity you gave up per decision, × 500: lower is better. About 5 is expert play, 10 a strong club player, 20 someone still learning. Each decision is graded: best or fine, an inaccuracy (yellow), a mistake (orange) or a blunder (red). Review the match to step through them on the board — your play in blue, the engine’s in gold — with the equities of the best few plays, or for the cube, no double, double/take and double/pass. The last twelve matches are kept on this device; your stats show them all.

Turn on the Tutor (Settings) and before a mistake stands it says so — what it gives up and what the engine would do — and you can take it back. Turn on Show the win chances for a bar by the board: your chances of winning, and of a gammon each way, after every play. Neither is there against a friend.