I think that this problem belongs to the small category of positions that suck to reason out. The best we can do is put it on our private hard disk.
Hitting is a high volatility move which turns out to be a lot better than playing safe.
If we play 6/5*, the opponent will miss in exactly half of the time, and our position will be so strong that he has to drop the cube. However, if he hits there is a big chance we lose a gammon, in case we don't enter in one or two times. However, if we do enter soon enough, we might get a second chance to drive him in the corner.
If we play 13/6, we leave 2 blots, and white's hitting chance will still be 11/36, while we don't have the upside of a tremendous offensive position.
With 16/15 7/1 we sabotage our big strategic asset to block white and get him ruin his board.
As in poker, in backgammon insight will not always be sufficient. Sometimes you also need “heart”.
Code:
1. 16/10 6/5* Eq.: +0,059
0,537 0,109 0,004 - 0,463 0,284 0,003 CL -0,101 CF +0,059
2. 13/6 Eq.: -0,117 (-0,176)
0,477 0,095 0,003 - 0,523 0,234 0,003 CL -0,185 CF -0,117
3. 16/15 7/1 Eq.: -0,131 ( -0,190)
0,479 0,099 0,002 - 0,521 0,231 0,004 CL -0,175 CF -0,131
Truncated cubeful rollout (depth 10) with var.redn.
147 games, Mersenne Twister dice gen. with seed 764949032 and quasi-random dice
Stop when std.errs. are small enough: ratio 0,1 (min. 144 games)
Play: world class 2-ply cubeful prune [world class]
keep the first 0 0-ply moves and up to 8 more moves within equity 0,16
Skip pruning for 1-ply moves.
Cube: 2-ply cubeful prune [world class]
Last edited by yogiman; 01-14-2015 at 09:42 AM.