Key factors seems to be the containment potential/readiness for the bottom player (BP) and timing (before crunching further) for the top player (TP).
Race lead for the TP is as gigantic as it usually is in this type of positions and I don't think even a +/- 30 pips difference would change the focus much.
XGR++ has the original position at a .87 take, but the rollout reveals it's much worse than that. Still a small take. Probably a bigger one in a practical sense, as I think the BP has a much harder task to execute cleanly (as always in containment games).
BP hits and covers the bar with only 9 rolls. If he does only one of these things, the TP has some light on his way.
Interesting to note is that the taker seems to have somewhat smallish cube vig potential. For most positions at NMS it oscillates around .2 but here it's only ca. .1 (cubeless .53 x 2 = 1.06 - .95 = .11).
                           |
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| XGID=--a-BBBA-A--A-A--b-eaCbBd-:0:0:1:00:0:0:0:13:10 | |||||
| Blue on roll, cube action? | |||||
| Analyzed in Rollout | No double | Double/Take |
| Player Winning Chances: | 72,35% (G:22,07% B:0,88%) | 72,90% (G:22,72% B:1,04%) |
| Opponent Winning Chances: | 27,65% (G:14,41% B:0,46%) | 27,10% (G:14,34% B:0,67%) |
| Cubeless Equities | +0,530 | +1,112 |
| Cubeful Equities | ||
| No double: | +0,804 (-0,151) | ±0,017 (+0,787..+0,820) |
| Double/Take: | +0,954 | ±0,023 (+0,931..+0,977) |
| Double/Pass: | +1,000 (+0,046) | |
| Best Cube action: Double / Take | ||
| Rollout details | ||
| 1296 Games rolled with Variance Reduction. Moves: 3-ply, cube decisions: XG Roller | ||
| Double Decision confidence: | 100,0% | |
| Take Decision confidence: | 100,0% | |
| Duration: 27 minutes 06 seconds | ||
eXtreme Gammon Version: 2.19.208.pre-release, MET: Kazaross XG2
Variant A
Compared to the original position, the BP is adjusted 9/7 and the TP is adjusted 23/22. |
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| XGID=---aBBBB----A-A--b-eaCbBd-:0:0:1:00:0:0:0:13:10 | |||||
| Blue on roll, cube action? | |||||
| Analyzed in Rollout | No double | Double/Take |
| Player Winning Chances: | 74,17% (G:23,43% B:0,98%) | 74,93% (G:24,32% B:1,26%) |
| Opponent Winning Chances: | 25,83% (G:12,07% B:0,29%) | 25,07% (G:12,16% B:0,35%) |
| Cubeless Equities | +0,607 | +1,285 |
| Cubeful Equities | ||
| No double: | +0,893 (-0,107) | ±0,012 (+0,881..+0,904) |
| Double/Take: | +1,152 (+0,152) | ±0,022 (+1,130..+1,174) |
| Double/Pass: | +1,000 | |
| Best Cube action: Double / Pass | ||
| Rollout details | ||
| 1296 Games rolled with Variance Reduction. Moves: 3-ply, cube decisions: XG Roller | ||
| Double Decision confidence: | 100,0% | |
| Take Decision confidence: | 100,0% | |
| Duration: 23 minutes 49 seconds | ||
eXtreme Gammon Version: 2.19.208.pre-release, MET: Kazaross XG2
A 4-prime in place is miles better than a slotted 3-prime for containment purposes. Even though the TP's blot is moved up to the edge of it, the position is a big pass.
Variant B
Compared to the original position, the TP is adjusted 1/8.  |
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| XGID=--a-BBBA-A--A-A--c-eaCbBc-:0:0:1:00:0:0:0:13:10 | |||||
| Blue on roll, cube action? | |||||
| Analyzed in Rollout | No double | Double/Take |
| Player Winning Chances: | 67,76% (G:18,84% B:0,79%) | 68,29% (G:19,37% B:0,87%) |
| Opponent Winning Chances: | 32,24% (G:16,12% B:0,58%) | 31,71% (G:16,10% B:0,65%) |
| Cubeless Equities | +0,385 | +0,814 |
| Cubeful Equities | ||
| No double: | +0,652 | ±0,012 (+0,640..+0,664) |
| Double/Take: | +0,638 (-0,014) | ±0,017 (+0,621..+0,655) |
| Double/Pass: | +1,000 (+0,348) | |
| Best Cube action: No double / Take | ||
| Percentage of wrong pass needed to make the double decision right: 3,7% | ||
| Rollout details | ||
| 2592 Games rolled with Variance Reduction. Moves: 3-ply, cube decisions: XG Roller | ||
| Double Decision confidence: | 90,9% | |
| Take Decision confidence: | 100,0% | |
| Duration: 50 minutes 44 seconds | ||
eXtreme Gammon Version: 2.19.208.pre-release, MET: Kazaross XG2
Moving one of the ace-killed checkers back to the 8pt. for the TP translates into more timing before crunching. What might look like a small change, actually swings the easy double decision into a no double range. To me it's still a practical double since many will hesitate and might drop this.