XGID=-aADCCC--------a----c-dccA:1:-1:1:63:0:0:0:0:10I agree with you and I would like to add that it is similar to the trap play concept described by Steve Sax on the gammonvillage website. The only difference is that the trap is set inside, not on the 7-8 points. That's why I first looked at O's inner board points. If he had three points instead of four, hitting would be a serious option.
Score is X:0 O:0. Unlimited Game
+13-14-15-16-17-18------19-20-21-22-23-24-+
| O | | O O O O | +---+
| | | O O O O | | 2 |
| | | O O O O | +---+
| | | O |
| | X | |
| |BAR| |
| | | |
| | | X |
| | | X X X X |
| | | X X X X |
| | | X X X X X O |
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 84 O: 70 X-O: 0-0
Cube: 2, O own cube
X to play 63
Most people would not hit here, because the downside of getting another checker sent back is so large. QF would therefore say that X is supposed
to hit here. But no, the rollout below says that hitting is nearly a
double whopper.
The main point is that the "obvious" alternative of 5/2 puts O's
straggler behind a solid five-prime, which does a pretty good job of containment. If we apply the usual approximation that hitting almost
always wins if O dances (and loses if O hits) then we have to judge
whether the safe play wins more than 2/3 of the time. The answer,
according to XG, is yes, on account of X's far superior structure
and the close race. Even if O hits or escapes, X retains some amount
of counterplay.
But if you want a QF play, see the variant below.
1. Rollout-| Bar/19 5/2 eq:+0.428
Player: 72.74% (G:6.80% B:0.19%)
Opponent: 27.26% (G:0.56% B:0.00%)
Confidence: -#0.005 (+0.423..+0.433) - [100.0%]
2. Rollout-| Bar/19 4/1* eq:+0.251 (-0.177)
Player: 64.28% (G:13.84% B:0.39%)
Opponent: 35.72% (G:5.49% B:0.05%)
Confidence: -#0.005 (+0.246..+0.256) - [0.0%]
-| 1296 Games rolled with Variance Reduction.
Dice Seed: 271828
Moves: 3-ply, cube decisions: XG Roller
eXtreme Gammon Version: 2.19.211.pre-release
-------
Variant
-------
XGID=-AaDCCC--------a----c-dccA:1:-1:1:62:0:0:0:0:10
Score is X:0 O:0. Unlimited Game
+13-14-15-16-17-18------19-20-21-22-23-24-+
| O | | O O O O | +---+
| | | O O O O | | 2 |
| | | O O O O | +---+
| | | O |
| | X | |
| |BAR| |
| | | |
| | | X |
| | | X X X X |
| | | X X X X |
| | | X X X X O X |
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 83 O: 69 X-O: 0-0
Cube: 2, O own cube
X to play 62
1. Rollout-| Bar/19 4/2* eq:+0.255
Player: 64.44% (G:13.91% B:0.39%)
Opponent: 35.56% (G:5.30% B:0.06%)
Confidence: -#0.004 (+0.251..+0.260) - [100.0%]
2. Rollout-| Bar/19 3/1 eq:+0.208 (-0.047)
Player: 63.00% (G:7.76% B:0.21%)
Opponent: 37.00% (G:0.36% B:0.00%)
Confidence: -#0.004 (+0.205..+0.212) - [0.0%]
-| 1296 Games rolled with Variance Reduction.
Dice Seed: 271828
Moves: 4-ply, cube decisions: XG Roller+
Search interval: Large
eXtreme Gammon Version: 2.19.211.pre-release
---
Tim Chow
I agree with you and I would like to add that it is similar to the trap play concept described by Steve Sax on the gammonvillage website. The only difference is that the trap is set inside, not on the 7-8 points. That's why I first looked at O's inner board points. If he had three points instead of four, hitting would be a serious option.
On 12/14/2023 3:58 PM, atila...@gmail.com wrote:You're right, in trap plays we force the opponent to break his anchor. In the second stage, we try to put the blots on the bar. This position is similar to the second stage. Actually, the concept of trap play is still going on.
I agree with you and I would like to add that it is similar to the trap play concept described by Steve Sax on the gammonvillage website. The only difference is that the trap is set inside, not on the 7-8 points. That's why I first looked at O's inner board points. If he had three points instead of four, hitting would be a serious option.A "trap play" usually refers to forcing the opponent off an
anchor, right? Or are you/Steve Sax using the term "trap play" in a different sense?
---
Tim Chow
You're right, in trap plays we force the opponent to break his anchor. In the second stage, we try to put the blots on the bar. This position is similar to the second stage. Actually, the concept of trap play is still going on.
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