Backgammon

Backgammon is basically the original version of the modern board game Sorry!.

The board is marked into four quadrants. Both players try to get their pieces around the board, then off the board. They can’t start moving pieces off the board until they have all their pieces in their final quadrant.

The pieces start in a specific pattern, and the two players are moving in opposition to each other – one counter-clockwise and one clockwise, so their pieces “collide” and have to move “through” each other to get to their destination.

(Note: the fact that the board has little pointy triangles (called “points”) has no significance – they could just as easily be boxes or “spaces.” Also, you can have as many pieces as you want on a point. It doesn’t matter if they stretch beyond the physical mark on the board. Stack them up, if you like.)

Players roll two dice, then move their pieces the number on the dice – either two pieces, one for each die value, or the die values combined for one piece. If the player rolls doubles, they get four total moves, as if they rolled the same number on four dice.

There are two important movement rules which introduce all the strategy:

1. A player cannot land on a point (a space) with two or more of their opponents pieces on it. If a player has two or more pieces on a point, their opponent is “locked out” of that point. This might mean a player has no valid move, because their die rolls could only move them onto one of these points. If a player can’t move, they forfeit the turn. (You can sometimes “lock up” large stretches of the board, and leave your opponent only hoping for a high roll to get past you.)
2. If their opponent has a single piece on a point, the player can land there and kick that piece off to the center of the board (again, just like the game Sorry!). Their opponent then has to start that piece’s journey over on the next turn. In this way, a single piece on a point is “unprotected” and at risk.

The basic strategy is to move your pieces around the board to your final quadrant, then get them all off the board, all the while preventing your pieces from being unprotected (all alone on a point), and kicking your opponent’s unprotected pieces back to the start whenever possible.

Winning a game (by getting all your pieces one space off the board before your opponent), gives you points:

• A simple win gives you one point
• If you get all your pieces off before your opponent gets any pieces off, you get two points
• If your opponent still has pieces on the far side of the board (from their perspective), you get three points

A single game usually takes anywhere from 5 to 15 minutes. A match is multiple games. Playing to five or seven points is common.

There is another significant strategic element to the game: the “doubling cube” or “doubling die.” It is optional, but changes the nature of match play considerably –

The doubling cube is a die marked with 2-4-8-16-32-64 on its sides. At any time, either player can double the points at stake by presenting the doubling cube to their opponent with the “2” facing up. Their opponent can accept the doubling – so now the game is worth 2, 4, or 6 points – or concede the game and the single point.

A key point: those are the only two choices – the player cannot decline and keep playing.

If the player accepts the doubling, they keep the cube on their side, and they can choose to re-double to 4x at any point in the future. Again, the other player can accept the re-doubling – so now they’re playing for 4, 8, or 12 – or concede the game and the two points (because it was previously doubled).

A player that accepts a doubling keeps the doubling cube and only they can choose to double again. A game can theoretically be doubled six times, in which case it’s worth 64, 128, or 192 points. Every time the stakes double, the cube is passed back and forth between players.

So, if you think you’re safely ahead, double the stakes. Either your opponent accepts and you hope to win 2, 4, or 6 points, or they concede and you get a guaranteed one point. The risk of doubling is that your opponent accepts and then makes a stunning comeback.

A lot of games will end on a concession (“doubling out”), because it’s often obvious to a player that there’s no way they can win, and they’d rather give up one point than take a chance of giving up two. A player might just be waiting for a good roll which tilts the odds in their favor and gives their opponent no rational choice other to concede rather than double.

I asked on the backgammon subreddit about doubling and if it’s required. The response:

No, you don’t have to use the cube, especially if you’re just playing for fun. The cube is always used in tournament (match) play and is pretty much always used when playing for money in general