How to Play Backgammon

How to play backgammon fits on one page, and playing it well takes years. Two players, 15 checkers each, a board of 24 narrow triangles called points, and two dice. You race your checkers round the board in opposite directions, hitting your opponent’s lone checkers on the way, and the first to bear all 15 off wins. Add the doubling cube and it turns into one of the oldest games of judgement and odds there is, which is why it has always been played for money in clubs and cafés.

How to play backgammon: setup and moving

Each side starts with two checkers on their 24-point, five on the 13, three on the 8 and five on the 6. Your home board is points 1 to 6. Each turn you roll two dice and move one checker by each number, or one checker by both. A double means four moves: roll 6-6 and you move 6 pips four times.

You can land on any point that’s empty, holds your own checkers, or holds a single opposing checker. Landing on a single checker, called a blot, hits it: it goes onto the bar in the middle and has to come back in through your opponent’s home board before its owner can move anything else. You can’t land on a point with two or more opposing checkers. Build several of those in a row and you’ve made a prime that’s very hard to get past.

Once all 15 of your checkers are in your home board, you start bearing off, removing one checker for each die number that matches its point. The race of total pips you have to travel at the start is 167 each; the CasinoCalcs pip count calculator shows who’s ahead at any moment.

The doubling cube and the 25% rule

The cube is what makes backgammon a gambling game. It starts at 1, and before rolling either player can offer to double the stake. The other side can drop, losing what’s at stake now, or take, and the game goes on at 2 with the cube in their hands. Only they can redouble next.

The maths of taking is neat. Say the game is worth 1 point and you’re offered a double. Drop and you lose 1. Take and you play for 2: if you win a fraction p of the time, you average 2p − 2(1 − p) = 4p − 2. That equals −1 when p is 25%. So without gammons, take when you win at least a quarter of the time. Owning the cube makes taking a little better still, because you can redouble if things turn.

Gammons change the numbers. If your opponent bears off all 15 before you’ve borne off any, it’s a gammon and costs double; with a checker still in their home board or on the bar, a backgammon costs triple. A position where you might lose a gammon needs better winning chances to take.

Odds every player uses

Most decisions come down to how likely a roll is. A specific number, such as a 6 on either die, comes up 11 times in 36 rolls, about 31%. Hitting a blot six pips away is 17 in 36 because combinations like 5-1 and 4-2 also get there. The backgammon odds chart lists the chance of hitting at every distance and of entering from the bar.

If you play for money, play for stakes you’re happy to lose. BeGambleAware.org has free support if it stops being a game.