Discussion:
Attack!
(too old to reply)
Tim Chow
2020-06-02 00:43:04 UTC
Permalink
XGID=-A--aaDACB--eB---b-dBb----:1:-1:1:44:0:0:0:0:10

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 | | 2 |
| | | O | +---+
| | | O |
| | | |
| |BAR| |
| O | | |
| O | | X |
| O X | | X |
| O X X | | X |
| O X X X | | X O O X |
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 140 O: 154 X-O: 0-0
Cube: 2, O own cube
X to play 44

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Tim Chow
Paul Epstein
2020-06-07 09:28:08 UTC
Permalink
Post by Tim Chow
XGID=-A--aaDACB--eB---b-dBb----:1:-1:1:44:0:0:0:0:10
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 | | 2 |
| | | O | +---+
| | | O |
| | | |
| |BAR| |
| O | | |
| O | | X |
| O X | | X |
| O X X | | X |
| O X X X | | X O O X |
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 140 O: 154 X-O: 0-0
Cube: 2, O own cube
X to play 44
More an instructive example than a quiz.
It's very important not to slow down the attack
by being hit. So pointing on both checkers
is wrong because the attack stalls if O rolls any ace.
Hit both checkers, make a 3 point board, and be completely safe.
At the risk of pointing out the obvious, the play is 9/5*/1 8/4(2).

Obvious once pointed out, but easy to miss OTB.
A clarification: I say "pointing out the obvious" because
the sentence with "Hit both checkers" already defines the play
uniquely so one could argue (but it's a spectacularly silly argument)
that since the play is described in words, to notate the play is redundant.

Paul
Tim Chow
2020-06-08 00:51:42 UTC
Permalink
XGID=-A--aaDACB--eB---b-dBb----:1:-1:1:44:0:0:0:0:10

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 | | 2 |
| | | O | +---+
| | | O |
| | | |
| |BAR| |
| O | | |
| O | | X |
| O X | | X |
| O X X | | X |
| O X X X | | X O O X |
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 140 O: 154 X-O: 0-0
Cube: 2, O own cube
X to play 44

I like Paul's analysis.

1. Rollout¹ 9/5* 8/4*(2) 5/1 eq:+0.837
Player: 73.98% (G:50.89% B:0.43%)
Opponent: 26.02% (G:5.17% B:0.22%)
Confidence: ±0.008 (+0.829..+0.845) - [100.0%]

2. Rollout¹ 9/5*(2) 8/4*(2) eq:+0.751 (-0.086)
Player: 72.69% (G:45.70% B:0.69%)
Opponent: 27.31% (G:5.54% B:0.23%)
Confidence: ±0.008 (+0.742..+0.759) - [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

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Tim Chow

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