Spoiler
7/5 gives us a nice distribution at the expense of only 2 shots (after which he'll still have two checkers stuck behind a 5 prime). But I'm not convinced it's worth it, so I'll go for one of the safe plays.
4/2 keeps us even-ended, but 6/4 seems to be more flexible. I'll go for that.
6/4.
Spoiler
I think 4/2, the leading choice right now, is the worst of the 3 - piling up on the highest and lowest points in the board with no spares in between is a recipe for plenty of awkward rolls in the bearoff, while White has time to stick around. I think 6/4 is the best, but I'm not sure... there are a lot of sequences which are bad for us where a 5 leaves a blot inside the board. At least after 7/5 and a hit we still have two men trapped.
i opt for 7-5. Take a small risk now to avoid a big problem later. It smoothes out our distribution which is good for our bearoff. It avoids jagoff scenarios like him entering with 1-X followed by our 6-5 ( if we make one of the other plays ).
I amost have to wonder, if you're afraid to take a 2 number risk when hes on the bar, what will you do when the genuine tough choices present themselves.
Bob
Quote from: NIHILIST on May 20, 2012, 06:57:10 PMI amost have to wonder, if you're afraid to take a 2 number risk when hes on the bar, what will you do when the genuine tough choices present themselves.
This is why I put this choice in..I wonder about this risk...it does leave room for the 1-6 to completely break our fairly sure game here. It might make the next roll easier if he doesnt roll 6-1, but is that risk really worth it?
With his 4 point board, if he does roll 6-1, we may well end up snatching defeat from the jaws of victory.
Spoiler
I think arguments for both plays are sound, and they are probably quite close, but I'd like to take the two shot risk for superior distribution against his ace-point game.
rollout
Spoiler
A fairly close one: the better distribution after 7/5 is not worth leaving two shots, but 7/5 is better than prematurely burying a checker on the deuce.
XGID=abBBCBDB---------b-dbb-b--:1:1:1:62:4:1:0:5:10
1. Rollout¹ 6/4 eq:+0.632
Player: 81.71% (G:45.48% B:15.71%)
Opponent: 18.29% (G:0.12% B:0.00%)
Confidence: ±0.004 (+0.628..+0.635) - [100.0%]
Duration: 4 minutes 43 seconds
2. Rollout¹ 7/5 eq:+0.608 (-0.024)
Player: 80.56% (G:46.71% B:16.78%)
Opponent: 19.44% (G:0.16% B:0.01%)
Confidence: ±0.004 (+0.604..+0.612) - [0.0%]
Duration: 3 minutes 49 seconds
3. Rollout¹ 4/2 eq:+0.581 (-0.050)
Player: 79.21% (G:43.14% B:13.98%)
Opponent: 20.79% (G:0.13% B:0.01%)
Confidence: ±0.004 (+0.578..+0.585) - [0.0%]
Duration: 3 minutes 45 seconds
4. 2-ply 5/3 eq:+0.356 (-0.276)
Player: 69.96% (G:25.11% B:1.99%)
Opponent: 30.04% (G:2.08% B:0.08%)
¹ 1296 Games rolled with Variance Reduction.
Moves: 3-ply, cube decisions: XG Roller
eXtreme Gammon Version: 2.03, MET: Kazaross XG2
more rollout
Spoiler
Match score makes a difference here. At 0-0 to 5 and the cube centered, 7/5 is correct.
The reason is that 7/5 wins more gammons. 6/4 still wins more single games.
XGID=abBBCBDB---------b-dbb-b--:0:0:1:62:0:0:0:5:10
X:Player 1 O:Player 2
Score is X:0 O:0 5 pt.(s) match.
+13-14-15-16-17-18------19-20-21-22-23-24-+
| O | | O O O O |
| O | | O O O O |
| | | O |
| | | O |
| | | |
| |BAR| |
| | O | |
| | | X |
| | | X X |
| X | | X X X X X O |
| X | | X X X X X O |
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 70 O: 135 X-O: 0-0/5
Cube: 1
X to play 62
1. Rollout¹ 7/5 eq:+1.074
Player: 82.37% (G:40.47% B:3.83%)
Opponent: 17.63% (G:0.15% B:0.00%)
Confidence: ±0.008 (+1.066..+1.081) - [99.6%]
Duration: 10 minutes 16 seconds
2. Rollout¹ 6/4 eq:+1.058 (-0.015)
Player: 83.09% (G:38.37% B:3.51%)
Opponent: 16.91% (G:0.09% B:0.00%)
Confidence: ±0.008 (+1.050..+1.067) - [0.4%]
Duration: 9 minutes 49 seconds
¹ 1296 Games rolled with Variance Reduction.
Moves: 3-ply, cube decisions: XG Roller
eXtreme Gammon Version: 2.03, MET: Kazaross XG2