Backgammon rules
Strategy guide →The goal
Move all fifteen of your checkers into your home board and then off the board entirely. Your opponent is doing the same in the opposite direction, around the same twenty-four points, which is why this is a race you can interfere with.
Rolling and moving
Roll two dice and move that many points — one checker the total, or two checkers one die each. Rolling a double gives you that number four times. You must play both numbers if any legal sequence allows it, even when doing so hurts you.
Blocked points and blots
A point with two or more enemy checkers is closed to you. A point with exactly one is a blot: land on it and that checker goes to the bar. A blot is not a mistake in itself — leaving one where it is likely to be hit is.
Coming back from the bar
A checker on the bar re-enters in your opponent's home board, and nothing else may move until it does. If every point there is closed to you, you forfeit the roll — which is how a game can be over long before the checkers are.
The doubling cube
Before any roll of yours, you may offer to double the stake. Your opponent concedes and loses what the game is worth now, or takes it — and from then on only they may double next. One point becomes two, two becomes four, and a game you were losing slowly becomes a decision.
The full rules
Overview
Backgammon is a two-player race around twenty-four positions, arranged as two rows of twelve facing each other. Each player owns fifteen checkers and travels the circuit in the opposite direction to their opponent, which is the whole source of the interference: every position one player is heading towards is one the other has already left or is sitting on.
A single game is won by bearing all fifteen checkers off, and is worth one, two or three points depending on how far behind the loser was. A match here is the first player to five points, and each player has eight minutes on the clock with ten seconds added back after every move.
The board, and which way you are going
The twenty-four points are numbered from each player's own point of view: your 24 point is the one furthest from you, your 1 point the nearest. Your opponent's numbering runs the other way, so your 24 point is their 1 point — the same triangle with two names.
The six points nearest you are your home board, and that is where your checkers have to end up. Everything in the game is measured in pips, which is simply points travelled.
| Region | Your points | What happens there |
|---|---|---|
| Home board | 1–6 | Where you bear off from, and where your opponent re-enters |
| Outer board | 7–12 | The stretch most checkers cross twice |
| Opponent's outer board | 13–18 | Where your midpoint stack starts |
| Opponent's home board | 19–24 | Where your back checkers start, and where they can be trapped |
The bar is not a point. It is where hit checkers wait, and a checker there has travelled backwards past your 24 point.
The starting position
The opening position is fixed and is the same for both players, mirrored. Fifteen checkers each, in four stacks.
| Point | Checkers | Distance home |
|---|---|---|
| 24 | 2 | Furthest; these are the ones that get trapped |
| 13 | 5 | The midpoint — the stack most plays draw from |
| 8 | 3 | Already past the halfway mark |
| 6 | 5 | Already home |
Two, five, three and five is fifteen checkers, and 167 pips of travel. Both numbers are worth checking against the table above: this rulebook shipped a first draft with three on the six point, which is thirteen checkers and 155 pips, and said 167 underneath it.
A turn
Roll two dice. Each die is a separate move of that many points, made by one checker in one direction — always towards your own 1 point. One checker may play both numbers in sequence, or two checkers may play one each.
When both dice show the same number you play that number four times, with any combination of checkers.
A move must end on a point that is open to you: empty, yours, or holding exactly one enemy checker.
Playing both numbers is compulsory whenever any legal sequence allows it — including sequences that damage your position.
If you can play either number but not both, you must play the larger one.
If neither number can be played, you forfeit the roll — see #forfeiting-a-roll.
A checker may pass over a blocked point; only the point it lands on has to be open.
Hitting, and the blot
A point holding exactly one enemy checker is a blot. Landing on it sends that checker to the bar, and it must travel the whole board again from the far end.
Hitting is not only about the pips you cost them. A checker on the bar cannot move anything else until it re-enters, so a hit at the right moment costs your opponent a turn as well as ground — and a hit in front of a strong home board can cost them several.
Entering from the bar
A checker on the bar re-enters in your opponent's home board, on the point matching a die. A roll of 3 enters on their 3 point. Nothing else on the board may move while you have a checker on the bar — not one checker, not one pip.
If the point a die names is held by two or more enemy checkers, that die cannot enter. If neither die can, you forfeit the entire roll.
When you cannot move
A roll with no legal move at all is forfeited and play passes. This is not a special rule so much as a consequence of the ones above, and it is the single most powerful thing that can happen to you.
A player facing a closed board — all six of the opponent's home points made — with a checker on the bar cannot move at all, and will not until the opponent is forced to break a point. Games are won this way without a single further decision.
Bearing off
Once all fifteen of your checkers are in your home board, you may start removing them. A die of 4 takes a checker off your 4 point.
If the point a die names is empty, you must move a checker within the home board using that number if you legally can. Only when no checker sits on a higher point may that die take a checker from the highest occupied point.
A checker hit while you are bearing off goes back to the bar and has to travel the whole board again — and you may not bear off another checker until it is home. Leaving a blot during the bear-off is how a won game is lost.
What a game is worth
Every game is worth at least one point, multiplied by the doubling cube. How much more depends on how far behind the loser was at the moment the winner's last checker came off.
| Result | Condition | Points |
|---|---|---|
| Single | The loser has borne off at least one checker | 1 × cube |
| Gammon | The loser has borne off none | 2 × cube |
| Backgammon | The loser has borne off none, and is still on the bar or inside the winner's home board | 3 × cube |
This is why a losing player races to bear off one checker, and why a winning player sometimes delays. The difference between a single and a gammon is a whole extra point.
The doubling cube
The cube starts in the middle at 1, belonging to nobody. Before any roll of your own, you may offer to double: your opponent either concedes immediately and loses the current value, or accepts, the cube turns to 2, and it moves to their side.
Only the player holding the cube may double next, which is the whole tension of it. Doubling gives away the right to double again, so the question is never only "am I ahead" but "am I ahead enough that giving up the cube is worth it".
A player who is offered a double and is too far behind to win should concede. Taking a double you cannot win costs twice what conceding does.
The match, and the Crawford rule
A match runs to five points. Game results accumulate, the cube multiplies them, and the first player to five wins however far past five they go.
When one player first reaches four — one point from the match — the next game is played with no cube at all. That is the Crawford game, and it exists because without it the trailing player would double immediately every game with nothing to lose.
After the Crawford game the cube returns, and the trailing player usually does double immediately, for exactly that reason.
What we deliberately do not play
Backgammon carries a large family of optional conventions. Almost all of them come from money play, where there is no match score to protect and a session ends when the players stop — so the conventions exist to manage variance and pace, neither of which is a problem a five-point match has.
Four are common enough that somebody will expect them, and none is implemented here.
Beavers, and the raccoons that follow them: taking a double and immediately turning it again while keeping the cube. A match has a ceiling, so a redouble chain can exceed the points left to win.
Automatic doubles on an opening tie. The cube moves without either player deciding anything, which is the opposite of what the cube is for.
The Jacoby rule, which withholds gammons and backgammons until the cube has been turned. It changes what a game is worth, and #what-a-game-is-worth is a table this page is read for.
Settlements — agreeing a fractional result mid-game. There is no fractional point in a match to five.
None of it is playable here yet — Backgammon is on the workshop bench, and what gets built next is decided by the vote on the shelf.
What a table looks like here
Two players, rated with Glicko-2, on an eight-minute clock with ten seconds added back after each move. Nothing is hidden — both players see the whole board and both dice — so matches can be watched.
It can also be played a move at a time over hours or days, which suits a game where the interesting decisions reward thinking about them.