Journal — 02
The doubling cube — the heart of the game
A cube with no pips, marked 2 to 64. It is never thrown. And it is the reason adults take backgammon seriously.
Most people who played backgammon as children never used the doubling cube. It sat in the box, nobody knew what it was for, and it stayed there. That is a shame, because without it backgammon is a dice game. With it, backgammon is a game about judgement.
What it does
The cube shows 2, 4, 8, 16, 32 and 64. It starts neutral in the middle. A player who thinks they are ahead may double before their roll: turn the cube to 2 and push it across. The opponent then has two options. Take — the game continues for twice the stake, and only they may double next time. Or drop — the game ends immediately and they pay the current value.
Why that changes everything
Without the cube you play every game to the end, including the hopeless ones. With it you have to answer, constantly, a question the board does not answer for you: how good is my position, really?
And you have to answer before you can know. Double too early and your opponent takes, and you have doubled the stake on their behalf. Double too late and they drop, and you collect a single point for a game you were winning enormously.
The best moment to double is roughly the last moment at which your opponent would still take.
The beginner's rule of thumb
Here is the number that surprises people: you should take a double if you would still win the game about a quarter of the time. Not half. A quarter. The reason is that dropping loses for certain, while taking keeps alive the possibility of doubling back later.
Almost every beginner drops too often. They see they are behind and they give up. Watch that for a while and you will win a lot of points simply by taking more bravely than everyone else.
The real appeal
The cube turns a game of chance into a negotiation. You are not only reading the board, you are reading the person: how certain are they? Are they doubling from strength or impatience? Are they taking because they counted, or because they don't want to look like a coward?
That is why there is a cube on every table at our meets, including the first games. You don't have to use it straight away. But you should know it's there.
The full rules are here — the cube has its own section.