The Rule of Symmetry

Symmetry is a concept in backgammon which doesn’t get much airtime, but I would argue it is as important as other household favourite concepts such as diversification and duplication, and it will go a long way to help you finding the correct play. 

Firstly, hitting in the opening game is almost always reciprocal. If your opponent hits you, then you should hit back.

Here you have the option to make the anchor but anything besides hitting back would be a big blunder. Hitting back will even the race and take away half of your opponent’s roll. Even if green had played the 2 by splitting her back checkers instead of bringing one down, it would still be a huge blunder not to hit.

This rule holds true in innumerable opening positions (such as below) where the symmetry of hitting plays a huge part, often taking precedence over making an anchor.

Another important rule of symmetry is: if your opponent has split her back checkers to make an anchor, then it is often the case that you split also to aim to make an anchor yourself. Take the position below:

Here green has split, so do the same and split also. Playing anything else would be an error. Here you give green a tough choice on their next roll: if they roll a 31 (or even 62), do they attack you or make an advanced anchor? 

Notice below that even if green has the stronger home board, it would still be correct to split. Anything besides 24/22 with the 2 would be an error.

Even in the below position when our opponent has us out-boarded 3-to-1, anything besides splitting is an error.

The final rule of symmetry is when your opponent makes a point, it is often right to do the same yourself to equalise your home board strength, which is important if a hitting contest occurs. Below, anything besides making the two-point is an error. This play would be correct also if green had the three- or four-point made. The exception is the five-point where you run.

Notice that making a point outright is often better than splitting your back checkers, which in turn is often better than hitting loose in your home board. There is a hierarchy to things over the board that you’ll get used to over time. Below making the three-point is right and anything else is an error.

And now below, splitting with both is better than hitting on the two-point.

And remember that two things are better than one. Here below we can hit and we can split our back checkers, which is the right play.

Of course, like anything in backgammon, these rules do not hold fast all the time – and spending time on XG will throw up many head-scratching exceptions. However, I believe that the rule of symmetry is true enough to act as guide to help you find the right play over the board, and that’s better than nothing.

Dan Rovira has the UK’s leading YouTube backgammon learning channel at @BackgammonIsBeautiful