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5a 4a awkward 42 to play

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Walt

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Apr 20, 2013, 8:47:41 PM4/20/13
to


XGID=----B-DbB---aEa--cce----B-:0:0:1:42:0:1:0:5:10

X:You O:O
Score is X:0 O:1 5 pt.(s) match.
+13-14-15-16-17-18------19-20-21-22-23-24-+
| X O O O | | O X |
| X O O | | O X |
| X O O | | O |
| X | | O |
| X | | O |
| |BAR| |
| | | |
| | | X |
| | | X |
| X O | | X X |
| O X O | | X X |
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 161 O: 135 X-O: 0-1/5
Cube: 1
X to play 42

badgolferman

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Apr 20, 2013, 10:13:09 PM4/20/13
to
I know the bot will hate this but I'll play 24/20, 6/4. Might as well
start the hitting while O's home board is wide open.

Bradley K. Sherman

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Apr 20, 2013, 10:33:53 PM4/20/13
to
Walt <walt_...@yahoo.com> wrote:
>Score is X:0 O:1 5 pt.(s) match.
> +13-14-15-16-17-18------19-20-21-22-23-24-+
> | X O O O | | O X |
> | X O O | | O X |
> | X O O | | O |
> | X | | O |
> | X | | O |
> | |BAR| |
> | | | |
> | | | X |
> | | | X |
> | X O | | X X |
> | O X O | | X X |
> +12-11-10--9--8--7-------6--5--4--3--2--1-+
> X:161 O:135, Cube:1, X to play 42

I want to hold the ace point here, so
13/9,6/4

--bks

crf

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Apr 21, 2013, 3:56:21 AM4/21/13
to
I was thinking split, too, but 24/22, 13/9 to reduce coming under the gun/being pointed on. The blot on 9 isn't as bad as it might look -- O will probably prefer to extend their prime with most 2s, but even if O hits, we already trail anyway and will then have good chances at a decent anchor.

Tim Chow

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Apr 21, 2013, 2:36:22 PM4/21/13
to
We're way behind in the race and O's stacks are just itching to unload
on a blot. I'm not splitting here. 13/9 is my 4 and I'm trying to
decide whether 13/11 is too blotty. It seems like we're going to get
the cube regardless. O.K., it could be too bold but I'll go for 13/11
13/9 since O has plenty of good things to do besides break anchor to
hit our blots and it's the fastest way to build a good forward
position.

---
Tim Chow

Walt

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Apr 22, 2013, 3:58:47 PM4/22/13
to

A difficult play, and I'm not sure I understand it. In fact I'm sure I
don't understand it. I was hoping for some hints from the group, so
thanks, Craig's.

XGID=----B-DbB---aEa--cce----B-:0:0:1:42:0:1:0:5:10

X:Player 1 O:Player 2
Score is X:0 O:1 5 pt.(s) match.
+13-14-15-16-17-18------19-20-21-22-23-24-+
| X O O O | | O X |
| X O O | | O X |
| X O O | | O |
| X | | O |
| X | | O |
| |BAR| |
| | | |
| | | X |
| | | X |
| X O | | X X |
| O X O | | X X |
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 161 O: 135 X-O: 0-1/5
Cube: 1
X to play 42

1. XG Roller++ 24/22 13/9 eq:-0.779
Player: 35.31% (G:6.97% B:0.27%)
Opponent: 64.69% (G:19.82% B:0.70%)

2. XG Roller++ 24/20 13/11 eq:-0.832 (-0.053)
Player: 34.77% (G:7.35% B:0.33%)
Opponent: 65.23% (G:20.81% B:0.93%)

3. XG Roller++ 13/11 13/9 eq:-0.832 (-0.054)
Player: 33.68% (G:7.42% B:0.28%)
Opponent: 66.32% (G:19.07% B:1.29%)

4. XG Roller++ 24/22 24/20 eq:-0.851 (-0.072)
Player: 34.33% (G:6.12% B:0.24%)
Opponent: 65.67% (G:19.44% B:0.50%)

5. XG Roller++ 13/9 6/4 eq:-0.904 (-0.125)
Player: 32.25% (G:6.84% B:0.24%)
Opponent: 67.75% (G:17.93% B:0.96%)


eXtreme Gammon Version: 2.10, MET: Kazaross XG2

--
//Walt

Tim Chow

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Apr 22, 2013, 7:17:35 PM4/22/13
to
On Apr 22, 3:58 pm, Walt <walt_ask...@yahoo.com> wrote:
> A difficult play, and I'm not sure I understand it.  In fact I'm sure I
> don't understand it.  I was hoping for some hints from the group, so
> thanks, Craig's.

This is a great problem. I'm sure that by varying the position
"slightly" we can get a variety of plays to come out on top. I'll see
if I can do that sometime soon.

There are a couple of competing principles at work. One is the one I
decided to go with, which is that if you're far behind in the race and
the opponent has stacks of checkers waiting to attack, then it's
better to settle for a deep anchor game rather than split and get
attacked.

Another principle, however, is that if the opponent has made an
advanced anchor then your best bet is to make an advanced anchor of
your own, so you should split even when it looks dangerous to do so.
This applies if the opponent is not already so far advanced that you
need to stay back to maximize contact.

The two principles above are strategic principles. Here I think a
tactical consideration comes into play, because of O's blots.
Splitting gives us some immediate chances of sending one of O's
checkers back.

Anyway, those are the ideas that I would explore and test by varying
the position.

---
Tim Chow

Tim Chow

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Apr 23, 2013, 9:57:31 PM4/23/13
to
O.K., here are truncated rollouts of some variant positions. I have
switched to a money game and given X the cube in order to screen out
any score/cube effects. (Note that giving X the cube has the effect
of approximately halving the equity differences because O is on the
verge of a cube in the original position.)

The first position is just Walt's original position. The other three
positions illustrate variants in which my play of 13/11 13/9 is at
least much closer. Basically, the further behind X is in the race,
and the more O's position is conducive to attacking rather than
priming, the less attractive it is to split.

======================================================

XGID=----B-DbB---aEa--cce----B-:1:1:1:42:0:0:1:0:10

X:Player 1 O:Player 2
Score is X:0 O:0. Money session
+13-14-15-16-17-18------19-20-21-22-23-24-+
| X O O O | | O X |
| X O O | | O X |
| X O O | | O |
| X | | O |
| X | | O |
| |BAR| |
| | | |
| | | X |
| | | X | +---+
| X O | | X X | | 2 |
| O X O | | X X | +---+
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pipcount X: 161 O: 135 X-O: 0-0
Cube : 2, X own cube
X to play 42

1. Rollout: 24/22 13/9 eq:-0.309
Player : 35.23% (G:7.47% B:0.33%)
Opponent: 64.77% (G:20.45% B:0.83%)
Confidence: ±0.008 (-0.317<E<-0.301)

2. Rollout: 24/20 13/11 eq:-0.322 (-0.013)
Player : 34.66% (G:7.24% B:0.35%)
Opponent: 65.34% (G:20.37% B:0.92%)
Confidence: ±0.008 (-0.330<E<-0.314)

3. Rollout: 24/22 24/20 eq:-0.335 (-0.026)
Player : 34.37% (G:6.31% B:0.26%)
Opponent: 65.63% (G:20.05% B:0.59%)
Confidence: ±0.007 (-0.342<E<-0.328)

4. Rollout: 13/11 13/9 eq:-0.336 (-0.027)
Player : 33.41% (G:7.49% B:0.29%)
Opponent: 66.59% (G:18.49% B:1.28%)
Confidence: ±0.008 (-0.344<E<-0.328)

5. Rollout: 13/9 6/4 eq:-0.363 (-0.054)
Player : 32.37% (G:6.93% B:0.27%)
Opponent: 67.63% (G:18.31% B:1.07%)
Confidence: ±0.007 (-0.370<E<-0.356)

6. Rollout: 24/20 6/4 eq:-0.371 (-0.062)
Player : 32.98% (G:6.14% B:0.25%)
Opponent: 67.02% (G:19.98% B:0.66%)
Confidence: ±0.007 (-0.378<E<-0.364)

Truncated at 7 moves using 3 ply.
324 Games rolled with Variance Reduction.
Dice Seed: 2
First 2 moves and cube decisions: 3 ply
Remaining moves: 2 ply, cube decisions: 3 ply

======================================================

XGID=----B-DbB---aE---dce----B-:1:1:1:42:0:0:1:0:10

X:Player 1 O:Player 2
Score is X:0 O:0. Money session
+13-14-15-16-17-18------19-20-21-22-23-24-+
| X O O | | O X |
| X O O | | O X |
| X O O | | O |
| X O | | O |
| X | | O |
| |BAR| |
| | | |
| | | X |
| | | X | +---+
| X O | | X X | | 2 |
| O X O | | X X | +---+
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pipcount X: 161 O: 132 X-O: 0-0
Cube : 2, X own cube
X to play 42

1. Rollout: 13/11 13/9 eq:-0.285
Player : 35.03% (G:7.89% B:0.29%)
Opponent: 64.97% (G:17.78% B:1.27%)
Confidence: ±0.008 (-0.293<E<-0.277)

2. Rollout: 24/20 13/11 eq:-0.298 (-0.012)
Player : 35.44% (G:6.70% B:0.25%)
Opponent: 64.56% (G:19.04% B:0.78%)
Confidence: ±0.008 (-0.306<E<-0.290)

3. Rollout: 24/22 13/9 eq:-0.298 (-0.013)
Player : 35.67% (G:7.43% B:0.29%)
Opponent: 64.33% (G:20.37% B:0.81%)
Confidence: ±0.008 (-0.306<E<-0.290)

4. Rollout: 13/9 6/4 eq:-0.312 (-0.027)
Player : 33.87% (G:7.34% B:0.26%)
Opponent: 66.13% (G:17.13% B:1.12%)
Confidence: ±0.008 (-0.320<E<-0.304)

5. Rollout: 24/22 24/20 eq:-0.314 (-0.028)
Player : 34.52% (G:5.56% B:0.20%)
Opponent: 65.48% (G:17.51% B:0.46%)
Confidence: ±0.008 (-0.322<E<-0.306)

6. Rollout: 13/11 6/2 eq:-0.320 (-0.035)
Player : 33.95% (G:7.48% B:0.25%)
Opponent: 66.05% (G:18.02% B:1.26%)
Confidence: ±0.008 (-0.328<E<-0.312)

7. Rollout: 24/20 6/4 eq:-0.326 (-0.041)
Player : 33.92% (G:6.04% B:0.23%)
Opponent: 66.08% (G:17.77% B:0.54%)
Confidence: ±0.007 (-0.333<E<-0.319)

Truncated at 7 moves using 3 ply.
324 Games rolled with Variance Reduction.
Dice Seed: 2
First 2 moves and cube decisions: 3 ply
Remaining moves: 2 ply, cube decisions: 3 ply

======================================================

XGID=----B-D-B-b-aEa--cce----B-:1:1:1:42:0:0:1:0:10

X:Player 1 O:Player 2
Score is X:0 O:0. Money session
+13-14-15-16-17-18------19-20-21-22-23-24-+
| X O O O | | O X |
| X O O | | O X |
| X O O | | O |
| X | | O |
| X | | O |
| |BAR| |
| | | |
| | | X |
| | | X | +---+
| O X | | X X | | 2 |
| O O X | | X X | +---+
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pipcount X: 161 O: 129 X-O: 0-0
Cube : 2, X own cube
X to play 42

1. Rollout: 24/22 13/9 eq:-0.428
Player : 29.77% (G:5.44% B:0.19%)
Opponent: 70.23% (G:17.60% B:0.66%)
Confidence: ±0.007 (-0.435<E<-0.421)

2. Rollout: 13/11 13/9 eq:-0.435 (-0.008)
Player : 27.97% (G:4.92% B:0.14%)
Opponent: 72.03% (G:13.27% B:0.88%)
Confidence: ±0.007 (-0.442<E<-0.428)

3. Rollout: 13/7 eq:-0.440 (-0.013)
Player : 27.66% (G:4.80% B:0.14%)
Opponent: 72.34% (G:12.91% B:0.71%)
Confidence: ±0.007 (-0.447<E<-0.433)

4. Rollout: 13/9 6/4 eq:-0.452 (-0.025)
Player : 27.10% (G:4.67% B:0.14%)
Opponent: 72.90% (G:12.79% B:0.80%)
Confidence: ±0.007 (-0.459<E<-0.445)

5. Rollout: 24/20 13/11 eq:-0.490 (-0.062)
Player : 28.54% (G:5.33% B:0.20%)
Opponent: 71.46% (G:20.35% B:0.97%)
Confidence: ±0.008 (-0.498<E<-0.482)

Truncated at 7 moves using 3 ply.
324 Games rolled with Variance Reduction.
Dice Seed: 2
First 2 moves and cube decisions: 3 ply
Remaining moves: 2 ply, cube decisions: 3 ply

======================================================

XGID=----B-DbB----Eb--cce----B-:1:1:1:42:0:0:1:0:10

X:Player 1 O:Player 2
Score is X:0 O:0. Money session
+13-14-15-16-17-18------19-20-21-22-23-24-+
| X O O O | | O X |
| X O O O | | O X |
| X O O | | O |
| X | | O |
| X | | O |
| |BAR| |
| | | |
| | | X |
| | | X | +---+
| X O | | X X | | 2 |
| X O | | X X | +---+
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pipcount X: 161 O: 133 X-O: 0-0
Cube : 2, X own cube
X to play 42

1. Rollout: 24/22 13/9 eq:-0.389
Player : 32.83% (G:6.22% B:0.25%)
Opponent: 67.17% (G:21.56% B:0.82%)
Confidence: ±0.007 (-0.396<E<-0.382)

2. Rollout: 13/11 13/9 eq:-0.398 (-0.009)
Player : 31.10% (G:6.04% B:0.20%)
Opponent: 68.90% (G:17.70% B:1.26%)
Confidence: ±0.007 (-0.405<E<-0.391)

3. Rollout: 24/22 24/20 eq:-0.426 (-0.036)
Player : 31.87% (G:5.74% B:0.23%)
Opponent: 68.13% (G:22.57% B:0.63%)
Confidence: ±0.007 (-0.433<E<-0.419)

4. Rollout: 13/11 6/2 eq:-0.432 (-0.043)
Player : 29.79% (G:5.80% B:0.19%)
Opponent: 70.21% (G:17.81% B:1.23%)
Confidence: ±0.007 (-0.439<E<-0.425)

5. Rollout: 13/9 6/4 eq:-0.433 (-0.043)
Player : 29.74% (G:5.53% B:0.21%)
Opponent: 70.26% (G:17.54% B:1.19%)
Confidence: ±0.006 (-0.439<E<-0.427)

6. Rollout: 24/20 13/11 eq:-0.441 (-0.051)
Player : 31.72% (G:6.17% B:0.24%)
Opponent: 68.28% (G:23.87% B:1.05%)
Confidence: ±0.007 (-0.448<E<-0.434)

Truncated at 7 moves using 3 ply.
324 Games rolled with Variance Reduction.
Dice Seed: 2
First 2 moves and cube decisions: 3 ply
Remaining moves: 2 ply, cube decisions: 3 ply

eXtreme Gammon Version: 1.21

---
Tim Chow
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