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Stick's Theory of Doubling at -3/-6

Posted By: Paul Weaver
Date: Tuesday, 3 August 2010, at 8:04 p.m.

Stick wrote:

"For those who have somehow missed the only thing I ever write at this and similar scores let me sum it up as best I can.

"At -3 -6 or greater when you're the -3 player and there's significant contact/gammon chances in the game you never have a double. You'll either be not good enough or too good at this score...sitting there and wasting your time by thinking about a cube is exactly that, a waste. Roll like you're in a bearoff v. bearoff position so people can come up to you after the match and say "but you didn't even think about cubing at -3 -6!??"

"Of course there will be exceptions but they will all fall into the ballpark of me (you) not giving a fuck. If you find those positions that squeeze into the nearly non existent window you will have missed a cube by .020, hardly worth caring about. You will have missed it by .020 and depending what MET you used, assuming G11 or R-K, you will then roll it out with the other one and it will be more or less of a cube, but never really exceed .020 at the end of the day.

"The only time you should really be cubing in such positions is if you think you may be in/around the window and your opponent might pass. Then it is acceptable to cube, otherwise just roll.

Stick"

In a practical sense, Stick's advice above is helpful, because it is very difficult for most players to figure out over the board when it is correct to double at -3/-6. I give Mochy a lot of credit for making a correct double at this score.

In a theortical sense, however, I question the accuracy of Stick's statements given above. Check out the six rollouts posted below. The first of these was done with the G11 MPT (match probability table). The remaining were done with Kaz-Rock MPT. Stick or anyone else is more than welcome to roll these same positions out using G11 or any other MPT. Comparing the first two positions posted below, you will notice that using a different MPT made a difference of at most 0.004 in the equity.





is mochy

score: 8
pip: 137
11 point match
pip: 149
score: 5

is peever
XGID=-aa---E-D--AbDb----cbbb-A-:0:0:-1:D:5:8:0:11:10
double to 2 take ?


Analyzed in Rollout
No Double
Player Winning Chances: 71.76% (G: 38.78% B: 2.00%)
Opponent Winning Chances: 28.24% (G: 5.36% B: 0.34%)
Double/Take
Player Winning Chances: 72.21% (G: 38.81% B: 3.74%)
Opponent Winning Chances: 27.79% (G: 5.22% B: 0.53%)
Cubeless Equities
No Double:+0.858
Double:+1.438
Cubeful Equities
No Double:+0.871 (-0.077)
Double/Take:+0.948
Double/Drop:+1.000 (+0.052)
Best Cube action: Double / Take
Rollout details
10368 Games rolled with Variance Reduction.
Moves and cube decisions: 3 ply
Confidence No Double: ± 0.007 (+0.864...+0.878)
Confidence Double: ± 0.010 (+0.938...+0.958)
Double Decision confidence: 100.0%
Take Decision confidence: 100.0%
Duration: 4 hours 02 minutes

eXtreme Gammon Version: 1.20, MET: Rockwell-Kazaross
is mochy

score: 8
pip: 137
11 point match
pip: 149
score: 5

is peever
XGID=-aa---E-D--AbDb----cbbb-A-:0:0:-1:D:5:8:0:11:10
double to 2 take ?


Analyzed in Rollout
No Double
Player Winning Chances: 71.77% (G: 38.79% B: 1.97%)
Opponent Winning Chances: 28.23% (G: 5.37% B: 0.34%)
Double/Take
Player Winning Chances: 72.22% (G: 38.82% B: 3.49%)
Opponent Winning Chances: 27.78% (G: 5.23% B: 0.53%)
Cubeless Equities
No Double:+0.858
Double:+1.438
Cubeful Equities
No Double:+0.867 (-0.080)
Double/Take:+0.947
Double/Drop:+1.000 (+0.053)
Best Cube action: Double / Take
Rollout details
10368 Games rolled with Variance Reduction.
Moves and cube decisions: 3 ply
Confidence No Double: ± 0.007 (+0.860...+0.874)
Confidence Double: ± 0.010 (+0.937...+0.957)
Double Decision confidence: 100.0%
Take Decision confidence: 100.0%
Duration: 3 hours 34 minutes

eXtreme Gammon Version: 1.20, MET: Rockwell-Kazaross
is Player 2

score: 8
pip: 136
11 point match
pip: 149
score: 5

is Player 1
XGID=-aa---E-D--AbDaa---cbbb-A-:0:0:-1:00:5:8:0:11:10
on roll, cube action?


Analyzed in Rollout
No Double
Player Winning Chances: 72.10% (G: 40.03% B: 1.81%)
Opponent Winning Chances: 27.90% (G: 5.27% B: 0.35%)
Double/Take
Player Winning Chances: 72.44% (G: 40.63% B: 3.52%)
Opponent Winning Chances: 27.56% (G: 5.35% B: 0.48%)
Cubeless Equities
No Double:+0.878
Double:+1.474
Cubeful Equities
No Double:+0.889 (-0.086)
Double/Take:+0.975
Double/Drop:+1.000 (+0.025)
Best Cube action: Double / Take
Rollout details
10368 Games rolled with Variance Reduction.
Moves and cube decisions: 3 ply
Confidence No Double: ± 0.007 (+0.882...+0.895)
Confidence Double: ± 0.010 (+0.965...+0.985)
Double Decision confidence: 100.0%
Take Decision confidence: 100.0%
Duration: 5 hours 00 minute

eXtreme Gammon Version: 1.20, MET: Rockwell-Kazaross
is Player 2

score: 8
pip: 137
11 point match
pip: 148
score: 5

is Player 1
XGID=-aa---E-D-A-bDb----cbbb-A-:0:0:-1:00:5:8:0:11:10
on roll, cube action?


Analyzed in Rollout
No Double
Player Winning Chances: 72.46% (G: 37.87% B: 1.87%)
Opponent Winning Chances: 27.54% (G: 5.21% B: 0.32%)
Double/Take
Player Winning Chances: 72.65% (G: 38.63% B: 3.62%)
Opponent Winning Chances: 27.35% (G: 5.16% B: 0.45%)
Cubeless Equities
No Double:+0.862
Double:+1.459
Cubeful Equities
No Double:+0.883 (-0.091)
Double/Take:+0.974
Double/Drop:+1.000 (+0.026)
Best Cube action: Double / Take
Rollout details
10368 Games rolled with Variance Reduction.
Moves and cube decisions: 3 ply
Confidence No Double: ± 0.007 (+0.876...+0.890)
Confidence Double: ± 0.010 (+0.964...+0.984)
Double Decision confidence: 100.0%
Take Decision confidence: 100.0%
Duration: 4 hours 38 minutes

eXtreme Gammon Version: 1.20, MET: Rockwell-Kazaross
is Player 2

score: 5
pip: 164
11 point match
pip: 155
score: 8

is Player 1
XGID=aa--BBB-B--AdD--ac-e--A-A-:0:0:1:00:8:5:0:11:10
on roll, cube action?


Analyzed in Rollout
No Double
Player Winning Chances: 73.63% (G: 31.72% B: 3.67%)
Opponent Winning Chances: 26.37% (G: 4.82% B: 0.38%)
Double/Take
Player Winning Chances: 73.52% (G: 34.29% B: 7.27%)
Opponent Winning Chances: 26.48% (G: 4.85% B: 0.45%)
Cubeless Equities
No Double:+0.844
Double:+1.437
Cubeful Equities
No Double:+0.894 (-0.066)
Double/Take:+0.960
Double/Drop:+1.000 (+0.040)
Best Cube action: Double / Take
Rollout details
1296 Games rolled with Variance Reduction.
Moves and cube decisions: 3 ply
Confidence No Double: ± 0.021 (+0.873...+0.914)
Confidence Double: ± 0.032 (+0.927...+0.992)
Double Decision confidence: 100.0%
Take Decision confidence: 99.2%
Duration: 1 hour 08 minutes

eXtreme Gammon Version: 1.20, MET: Rockwell-Kazaross
is Player 2

score: 5
pip: 166
11 point match
pip: 135
score: 8

is Player 1
XGID=aa-B--DBB---dCa--cBe------:0:0:1:00:8:5:0:11:10
on roll, cube action?


Analyzed in Rollout
No Double
Player Winning Chances: 73.49% (G: 34.26% B: 3.30%)
Opponent Winning Chances: 26.51% (G: 4.64% B: 0.29%)
Double/Take
Player Winning Chances: 73.19% (G: 37.38% B: 5.84%)
Opponent Winning Chances: 26.81% (G: 4.75% B: 0.45%)
Cubeless Equities
No Double:+0.868
Double:+1.472
Cubeful Equities
No Double:+0.916 (-0.077)
Double/Take:+0.993
Double/Drop:+1.000 (+0.007)
Best Cube action: Double / Take
Rollout details
10368 Games rolled with Variance Reduction.
Moves and cube decisions: 3 ply
Confidence No Double: ± 0.007 (+0.909...+0.923)
Confidence Double: ± 0.011 (+0.982...+1.004)
Double Decision confidence: 100.0%
Take Decision confidence: 88.9%
Duration: 5 hours 33 minutes

eXtreme Gammon Version: 1.20, MET: Rockwell-Kazaross

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