FIBS Board backgammon forum

You should double if there is even slight possibility to lose markets when your opponent is 2-away. This is a good rule of thumb. Like in this position very good rolls (61, 31, 11, 44, 33, 66, 55, 64) could lead to double, pass. But... i made a bad double in this score also. So you could add to rule: that you shouldn't double if you're not favorite to win (exceptions to that propably too when very likely to gammon). And also which I often forgot is that there are no market losers if opponent has solid high anchor (unless behind huge prime or big race lead).

Well this problem has been up long enough I think. This position, which is an excellent double by rollingfool and a clear take, belongs to a class of positions under the heading of "One way gammon threat, dead cube". After doubling, only Red benefits from a gammon and the cube is of no value to White. 3-away, 2-away and 4-away, 2-away are the scores at which you need to be alert to these. This cube would be even more potent at 4-away, 2-away, so much so that White should pass! That is because at 3-away, 2-away, Red has some wastage if he wins a doubled gammon; he can only use three of the four points for that. However, there is an upside too, which is that Red doesn't need to go crazy to win a gammon here, because a doubled plain game gets him to Crawford, where his winning chances are about 70%.
Instructive position. Learn and copy.