On 1/8/2022 10:01 AM,
peps...@gmail.com wrote:
I never know whether 42's play in the opening by hitting 13/7* or making the 4 point. Plus ca change, plus c'est la meme chose.
At least at a normal score, XG slightly favors 13/7* on the second roll
of the game (after 24/18 13/11 for example). But I'd guess that in most
other early-game situations where you're unsure, XG will prefer the 4pt. Chances are that in such situations, your board is weak and you're not
likely to launch a successful blitz, so 13/7* will typically be better
only if you need a tempo hit or need to prevent O from escaping her last checker. Here are a couple of examples.
------------------------------------------------------------------------
XGID=-a----EaC-B-eC---b-d-Bb---:0:0:1:42:0:0:0:0:10
X:Player 1 O:Player 2
Score is X:0 O:0. Unlimited Game
+13-14-15-16-17-18------19-20-21-22-23-24-+
| X O | | O X O |
| X O | | O X O |
| X | | O |
| | | O |
| | | |
| |BAR| |
| O | | X |
| O | | X |
| O X | | X |
| O X X | | X |
| O X X O | | X O |
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 155 O: 153 X-O: 0-0
Cube: 1
X to play 42
This position comes from a 2016 game between Falafel and MCG. There
is no urgent need to hit O's checker, and XG deems 13/7* a whopper
(pace Stick).
1. Rollout¹ 8/4 6/4 eq:+0.264
Player: 55.56% (G:15.68% B:0.51%)
Opponent: 44.44% (G:7.53% B:0.29%)
Confidence: ±0.013 (+0.252..+0.277) - [100.0%]
2. Rollout¹ 13/7* eq:+0.169 (-0.095)
Player: 53.43% (G:15.32% B:0.55%)
Opponent: 46.57% (G:10.21% B:0.46%)
Confidence: ±0.013 (+0.155..+0.182) - [0.0%]
¹ 1296 Games rolled with Variance Reduction.
Dice Seed: 271828
Moves: 3-ply, cube decisions: XG Roller
-------------------------------------------------------------------------
XGID=-a----EaC---dE---b-ebAA---:0:0:1:42:0:0:0:0:10
X:Player 1 O:Player 2
Score is X:0 O:0. Unlimited Game
+13-14-15-16-17-18------19-20-21-22-23-24-+
| X O | | O O X X |
| X O | | O O |
| X | | O |
| X | | O |
| X | | O |
| |BAR| |
| | | X |
| O | | X |
| O X | | X |
| O X | | X |
| O X O | | X O |
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 162 O: 150 X-O: 0-0
Cube: 1
X to play 42
There's an argument for a tempo hit here since X is unanchored and
O is poised to attack; nevertheless, XG still prefers the 4pt.
1. Rollout¹ 8/4 6/4 eq:-0.373
Player: 41.77% (G:10.21% B:0.50%)
Opponent: 58.23% (G:18.91% B:0.65%)
Confidence: ±0.007 (-0.380..-0.366) - [100.0%]
2. Rollout¹ 13/7* eq:-0.412 (-0.039)
Player: 40.80% (G:9.83% B:0.44%)
Opponent: 59.20% (G:19.34% B:0.95%)
Confidence: ±0.008 (-0.420..-0.404) - [0.0%]
¹ 5184 Games rolled with Variance Reduction.
Dice Seed: 271828
Moves: 3-ply, cube decisions: XG Roller
-------------------------------------------------------------------------
XGID=------EaCB--fB---c-e---AB-:0:0:1:42:0:0:0:0:10
X:Player 1 O:Player 2
Score is X:0 O:0. Unlimited Game
+13-14-15-16-17-18------19-20-21-22-23-24-+
| X O | | O X X |
| X O | | O X |
| O | | O |
| | | O |
| | | O |
| |BAR| |
| 6 | | X |
| O | | X |
| O X | | X |
| O X X | | X |
| O X X O | | X |
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 169 O: 150 X-O: 0-0
Cube: 1
X to play 42
Even here, where O is threatening to escape her last checker, XG
prefers to build the board with 8/4 6/4. O has no structure so
X will likely get another chance to hit soon enough, and then the
4pt will be a powerful asset.
1. Rollout¹ 8/4 6/4 eq:-0.063
Player: 47.33% (G:15.37% B:0.46%)
Opponent: 52.67% (G:11.05% B:0.68%)
Confidence: ±0.015 (-0.079..-0.048) - [100.0%]
2. Rollout¹ 24/20 9/7* eq:-0.154 (-0.091)
Player: 45.94% (G:13.93% B:0.50%)
Opponent: 54.06% (G:14.51% B:0.98%)
Confidence: ±0.016 (-0.170..-0.138) - [0.0%]
¹ 1296 Games rolled with Variance Reduction.
Dice Seed: 271828
Moves: 3-ply, cube decisions: XG Roller
-------------------------------------------------------------------------
XGID=-a---BDaC---eD---b-cc--AA-:0:0:1:42:0:0:0:0:10
X:Player 1 O:Player 2
Score is X:0 O:0. Unlimited Game
+13-14-15-16-17-18------19-20-21-22-23-24-+
| X O | | O O X X |
| X O | | O O |
| X | | O O |
| X | | |
| | | |
| |BAR| |
| O | | |
| O | | X |
| O X | | X |
| O X | | X X |
| O X O | | X X O |
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 157 O: 156 X-O: 0-0
Cube: 1
X to play 42
Here's one where XG strongly favors 13/7*. X has already made his 5pt
and 13/7* brings a tenth checker into the zone. If X is not hit back
right away then he has good chances of either blitzing or priming. It
also serves as a tempo hit to slow down O's offensive buildup. If X
were anchored on O's 4pt the decision would be much closer.
1. Rollout¹ 13/7* eq:+0.097
Player: 51.77% (G:17.81% B:0.82%)
Opponent: 48.23% (G:14.23% B:0.75%)
Confidence: ±0.017 (+0.080..+0.114) - [100.0%]
2. Rollout¹ 8/4 6/4 eq:+0.008 (-0.089)
Player: 49.65% (G:15.35% B:0.57%)
Opponent: 50.35% (G:12.49% B:0.52%)
Confidence: ±0.015 (-0.007..+0.023) - [0.0%]
¹ 1296 Games rolled with Variance Reduction.
Dice Seed: 271828
Moves: 3-ply, cube decisions: XG Roller
eXtreme Gammon Version: 2.19.207.pre-release
---
Tim Chow
--- SoupGate-Win32 v1.05
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