BGonline.org Forums

Mislav Kovacic's problem revisited

Posted By: Timothy Chow
Date: Wednesday, 14 May 2014, at 2:24 p.m.

In Response To: Do you have the guts to hit? (Mislav Kovacic)

I recently mentioned an old problem posted by Mislav Kovacic, "Do you have the guts to hit?" At the time, Casper van der Tak and Mary Hickey said that the opponent's immediate cube action from the bar was an important consideration. However, I was the only one who posted bot results, and I neglected to look into the effect of the cube.

White does have a double from the bar (not shown below) but the computer hits with a centered cube anyway. What's perhaps more interesting is that, according to the rollout results below, if Blue owned the cube, the bot would not hit. (I've changed the score to unlimited but I don't think this makes that much difference.) This means that if your opponent is an aggressive doubler who might double anyway after you play 9/4 9/3, then 9/4 9/3 might be the better play after all. (Of course, the fact that your opponent didn't double last turn is some evidence that she is not that aggressive a doubler.)

 White is Player 2 score: 0 pip: 112 Unlimited Game pip: 110 score: 0 Blue is Player 1
XGID=-ABAABBB-B-aba---bbc-bBb--:0:0:1:65:0:0:0:0:10
Blue to play 65

1.Rollout122/11* eq: -0.400
 Player:Opponent: 40.83% (G:17.47% B:0.72%)59.17% (G:29.97% B:3.35%) Conf.: ± 0.018 (-0.418...-0.382) - [100.0%]Duration: 7 minutes 14 seconds
2.Rollout19/4 9/3eq: -0.492 (-0.092)
 Player:Opponent: 36.94% (G:3.94% B:0.06%)63.06% (G:5.41% B:0.13%) Conf.: ± 0.010 (-0.502...-0.482) - [0.0%]Duration: 9 minutes 07 seconds
1 1296 Games rolled with Variance Reduction.
Dice Seed: 271828
Moves: 3-ply, cube decisions: XG Roller

eXtreme Gammon Version: 2.10

 White is Player 2 score: 0 pip: 112 Unlimited Game pip: 110 score: 0 Blue is Player 1
XGID=-ABAABBB-B-aba---bbc-bBb--:1:1:1:65:0:0:0:0:10
Blue to play 65

1.Rollout19/4 9/3eq: -0.180
 Player:Opponent: 36.76% (G:3.59% B:0.04%)63.24% (G:5.15% B:0.12%) Conf.: ± 0.005 (-0.185...-0.175) - [100.0%]Duration: 5 minutes 12 seconds
2.Rollout19/4 7/1eq: -0.196 (-0.016)
 Player:Opponent: 36.33% (G:3.81% B:0.03%)63.67% (G:5.47% B:0.19%) Conf.: ± 0.005 (-0.201...-0.190) - [0.0%]Duration: 4 minutes 12 seconds
3.Rollout122/11* eq: -0.200 (-0.020)
 Player:Opponent: 40.83% (G:17.47% B:0.72%)59.17% (G:29.97% B:3.35%) Conf.: ± 0.009 (-0.209...-0.191) - [0.0%]Duration: 7 minutes 18 seconds
1 1296 Games rolled with Variance Reduction.
Dice Seed: 271828
Moves: 3-ply, cube decisions: XG Roller

eXtreme Gammon Version: 2.10

Post Response

Subject:
Message: