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Should I prevent a back game in this situation

Started by pilzgift, December 29, 2014, 11:35:05 AM

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pilzgift

I have the following position in gnubg

GNU Backgammon  Position ID: 2NbgADSMt4MBJA
                 Match ID   : cAk3AAAAAAAE
+13-14-15-16-17-18------19-20-21-22-23-24-+     O: gnubg
| X           O  O |   | O  O  O  X     X |     0 points
| X           O    |   | O  O  O          |     
|                  |   |                  |     
|                  |   |                  |     
|                  |   |                  |   
v|                  |BAR|                  |     1 point match (Cube: 1)
|                  |   |                  |   
|                  |   | X                |     
| O           X    |   | X                |     
| O           X  X |   | X        X     O |     Rolled 65
| O           X  X |   | X        X  O  O |     0 points
+12-11-10--9--8--7-------6--5--4--3--2--1-+     X: pilzgift
                    Pip counts : O 163, X 140


The best play according to gnubg is to hit 24/18*/13. If he will re-enter from the bar, this will give him the opportunity to build a prime on the 2 and 1 point and the situation will possibly lead for him to play a back-game. I played against the advice of gnubg not hitting his 18 point and eventually won the game. Is it a good tactical decision to prevent the opponent to play back-games or prevent him to have a even number of checkers in my home (which can lead to a dangerous prime) as in this situation?

dorbel

Not hitting is, as Gnu told you, a big blunder. You are correct to say that generally speaking in this type of situation you want to avoid sending a fourth checker back, because it gives your opponent the chance to make a second anchor. Here though you pay a big price if you eschew the hit, because it leaves one of your men still on the ace point and it gives your opponent the opportunity to make a five prime with his next six or make his bar with an ace. It also allows him to play all of his next roll, notably 6-6, 3-3 and 6-3 his disaster rolls if he is on the bar, are now very bad for you. The swing on these four numbers alone is enormous. Even if he does make a 1-2 back game next turn, well that isn't very bad and certainly not as bad as the alternative.

pilzgift

I understand, thanks for your detailed explanation.  :cool: