Discussion:
Cube action from bar.
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Michael
2018-02-06 19:14:39 UTC
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GNU Backgammon Position ID: tmseABDYtiUAWA
Match ID : cAkAAAAAAAAE
+13-14-15-16-17-18------19-20-21-22-23-24-+ O: O
| O | | O O O O O X | 0 points
| O | | O O O O X |
| O | | O |
| O | | |
| | | |
v| |BAR| | (Cube: 1)
| | | |
| | | |
| | | |
| X X | | X X X | On roll
| X X X X | X | X X X O | 0 points
+12-11-10--9--8--7-------6--5--4--3--2--1-+ X: X
Pip counts : O 94, X 153
BlueDice
2018-02-06 21:03:54 UTC
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Post by Michael
GNU Backgammon Position ID: tmseABDYtiUAWA
Match ID : cAkAAAAAAAAE
+13-14-15-16-17-18------19-20-21-22-23-24-+ O: O
| O | | O O O O O X | 0 points
| O | | O O O O X |
| O | | O |
| O | | |
| | | |
v| |BAR| | (Cube: 1)
| | | |
| | | |
| | | |
| X X | | X X X | On roll
| X X X X | X | X X X O | 0 points
+12-11-10--9--8--7-------6--5--4--3--2--1-+ X: X
Pip counts : O 94, X 153
High volatility.
Gammons for both sides
D/T
--
BD
Tim Chow
2018-02-08 01:09:20 UTC
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Post by Michael
GNU Backgammon Position ID: tmseABDYtiUAWA
Match ID : cAkAAAAAAAAE
+13-14-15-16-17-18------19-20-21-22-23-24-+ O: O
| O | | O O O O O X | 0 points
| O | | O O O O X |
| O | | O |
| O | | |
| | | |
v| |BAR| | (Cube: 1)
| | | |
| | | |
| | | |
| X X | | X X X | On roll
| X X X X | X | X X X O | 0 points
+12-11-10--9--8--7-------6--5--4--3--2--1-+ X: X
Pip counts : O 94, X 153
O is in danger not only of getting another checker sent back but of crunching
even if she is not hit. Her straggler is not at the edge of X's five-prime.
Therefore the take/pass decision has to be considered carefully. I think
that O has enough chances of escaping to make this a take. If X does not
hit then X may have trouble extricating his back checkers and may have to
break his prime. So I would take as O, but since X has a definite edge and
will massively lose his market if he hits, I would double.

---
Tim Chow
Michael
2018-02-09 11:36:38 UTC
Permalink
Post by Michael
GNU Backgammon Position ID: tmseABDYtiUAWA
Match ID : cAkAAAAAAAAE
+13-14-15-16-17-18------19-20-21-22-23-24-+ O: O
| O | | O O O O O X | 0 points
| O | | O O O O X |
| O | | O |
| O | | |
| | | |
v| |BAR| | (Cube: 1)
| | | |
| | | |
| | | |
| X X | | X X X | On roll
| X X X X | X | X X X O | 0 points
+12-11-10--9--8--7-------6--5--4--3--2--1-+ X: X
Pip counts : O 94, X 153
While it's usually easy for us to cube when opponent is on bar, it's quite the opposite for the opponent to do so when he's on bar.
Usually there must be something juicy in our board to do so.
Still notice it's only a +0.03 Double at this position and a sure Take.

You may also have a look at the Variant where I moved O's checker from 19 to 20.

Cube analysis
Rollout cubeless equity +0.4097

Cubeful equities:
1. Double, take +0.6313
2. Double, pass +1.0000 ( +0.3687)
3. No double +0.6004 ( -0.0309)
Proper cube action: Double, take

Rollout details:
Centered 1-cube:
69.84 15.54 0.54 - 30.16 13.11 1.67 CL +0.4097 CF +0.6004
[ 0.14 0.11 0.01 - 0.14 0.11 0.03 CL 0.0036 CF 0.0064]
Player O owns 2-cube:
70.23 15.22 0.55 - 29.77 12.92 1.68 CL +0.8325 CF +0.6313
[ 0.16 0.13 0.02 - 0.16 0.11 0.03 CL 0.0077 CF 0.0092]

Variant
**********

Cube analysis
Rollout cubeless equity +0.3428

Cubeful equities:
1. No double +0.5726
2. Double, pass +1.0000 ( +0.4274)
3. Double, take +0.5184 ( -0.0542)
Proper cube action: No double, take (11.3%)

Rollout details:
Centered 1-cube:
69.40 11.08 0.35 - 30.60 14.18 1.78 CL +0.3428 CF +0.5726
[ 0.16 0.11 0.01 - 0.16 0.13 0.03 CL 0.0042 CF 0.0083]
Player O owns 2-cube:
69.88 10.88 0.35 - 30.12 13.79 1.74 CL +0.7089 CF +0.5184
[ 0.19 0.11 0.01 - 0.19 0.14 0.03 CL 0.0094 CF 0.0110]
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