When to Double and When to Go for the Gammon?

Here’s the situation, and we’ve all been there:  it’s fairly early in the game, and everything has gone well, and you’ve got a great position, and if all goes well, you might well win a gammon.  The only problem is, you haven’t doubled yet and the cube is in the middle.  So, if you win a gammon, you only get 2 points.  But if you double, he’ll probably drop.  And of course, if you don’t double and keep playing for the gammon , we all know that something can go wrong and you’ll lose a game you could have ended with the cube.  What should you do?

I wish I could give you a simple answer.  The answer is:  it depends on the position and it depends on the score.  In “money” games, or in games where neither player is within 5 points of match point in longer matches, the general rule is that you should play for the gammon if your odds of winning a gammon are twice as high as your odds of losing.  (Of course, in most money games, the Jacoby rule requires an initial double before there can be a gammon.) 

So in the above situation, the first thing you need to do is “estimate” your odds of winning a gammon and your odds of losing.  Even the best experts in the world have difficulty making this estimation, as it can be a very complex calculation.  But you have to try and do the best you can, and if you think you will win a gammon, say, one out of 4 times, or 25%, but you will lose the game only 1 out of 10, or 10%, then you’ve got an easy decision….go for the gammon. 

But what if you’re not so sure?  What if you really can’t tell, or if your “best guess” is that it’s close?  My advice to you, in that situation, is go ahead and double.  Why?  Because it’s better to make a mistake, if there is one, by doubling and just take the point.  The other thing that can happen is that your opponent just might make a mistake and take the cube!  And that’s a good thing.  What could be better than your opponent taking a cube that you think might even been too good to give?  Yes, you will lose sometimes, and it will backfire, but backgammon is all about odds and long-term statistics, and while you will lose many games you should win, you will also win just as many that you should lose…in the long run, luck, and the dice even out, and you must rely on the odds.

Now, what about those situations where one of you is 2 away from game and the other is 3 or 4 away, or you’re both 3 or 4 away.  Then the doubling decision becomes MUCH more complex, and again, I can’t give you an easy answer or formula.  This is one of the reasons why backgammon is such a complex, interesting, and truly skillful game….the math gets very complex.  To understand the answer, you must first understand and know “match equities.”  

I don’t intend to get into detail on this subject here, and if you really want to advance your game to a higher level, I strongly recommend you study any of the great books that cover match equities in detail…most people recommend Robertie’s books.  But to really play the game right, you need to know what your odds are of winning the match if you were to double and just win one point, if you don’t double and win 2 points, and if you don’t double and lose one point.  Then you have to weigh all those against the odds of the particular game and situation and determine if going for the gammon is worth the risk.  Depending on the score, there are situations where you are a big favorite to win a double, but you still shouldn’t give the cube because your opponent is better off accepting the cube and doubling you back.  Even if he does get gammoned a lot, his odds of winning the match are better with the cube on 4.  (For example, if the match is to 7, and you’re winning 4-0, you would have to have a VERY SURE position to give the cube, because if he takes it and gives it right back, you’ve give up a lot of advantage of your lead in the match if he get’s lucky and win’s the game.  And if he gets really lucky and gammons you, now he can even win the entire match in one game!)

So the simple answer is, the answer isn’t so simple.  One of my favorite expressions is “you don’t know what you don’t know,” and if you really want to get good at backgammon, the first thing you must realize is there’s a lot you don’t know.  The game is much more complex, mathematical, and multi-faceted than most people realize, and the more you study the game, the more you find out that you don’t know a lot.  Even the top players in the world find themselves in situations where they are just not sure of the right play or decision and run to the computer programs (Snowie and Jellyfish) to get some help with the answer.  (And as good as they are, some situations are still too baffling even for the programs!)

Sorry if this article confused you more than it helped, but I do hope it did give you the basic things you have to think about and consider when deciding whether or not to give the cube or go for the gammon.  I hope it gave you a general rule, which is:  when in doubt about whether to play for the gammon or not, it’s generally safer to give the cube.  And I hope it stimulated you to learn more.  To read, study the game more, and learn more.  The more you understand the game, and the better you get, the more interesting and fun the game is.