USBGF OLM 2020-10-10

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Last vote on the OLM:

is Neil Kazaross

score: 9
pip: 60
                         
11 point match
                          pip: 134
score: 2

is USBGF Members
XGID=-B-BBBC-------aa---cBacbdB:0:0:1:00:2:9:0:11:10
on roll, cube action?

Analyzed in Rollout No double Double/Take
  Player Winning Chances: 33.96% (G:14.20% B:1.01%) 34.02% (G:14.23% B:1.00%)
  Opponent Winning Chances: 66.04% (G:44.75% B:0.83%) 65.98% (G:51.39% B:0.38%)
  Cubeless Equities -0.901 -0.617
Cubeful Equities
     No double:-0.765 (-0.148)±0.005 (-0.770..-0.759)
played Double/Take:-0.617±0.007 (-0.623..-0.610)
     Double/Pass:+1.000 (+1.617)
 
Best Cube action: Double / Take
Rollout details
1296 Games rolled with Variance Reduction.
Dice Seed: 75274404
Moves: 4-ply, cube decisions: XG Roller+
 
Double Decision confidence:100.0%
Take Decision confidence:100.0%
Duration: 41 minutes 12 seconds

eXtreme Gammon Version: 2.10, MET: Kazaross XG2

USBGF Members vote:
[27] Double
[ 8] No Double


Grant Hoffman (grant@hoffman.kiwi)
teaches at the Backgammon Learning Center, and can be contacted for lessons via email.

Grant Hoffman recommends: Double

First let’s think whether this would be a double for money. Although we hit with 12 numbers (any 4 as well as 55) we do not hit with 24 numbers. For money this would have to be a beaver.

We are trailing 9 away 2 away, so really need to get some points on the board. Because of how desperate we are we should double here. Yes this means if we lose then we will lose the match, but even without the cube turned, Neil will win about 45% Gammons, and therefore the match. This means we are not giving up much by doubling, but the reward of winning maybe 4 points is huge. So double and let’s see what happens.


Kimon Papachristopoulos recommends: Double

We do not risk much by doubling. We will lose only few single games and then at Crawford 9 away our prospects remain poor. By doubling we may gain extra two points what helps considerably in winning the match.

A rough estimate of the odds looks like that: At Crawford 9 away we will have about 5% but we can get there only if we do not hit, 67% and then save the gammon 25%+x what totals in maybe 15% of all games. 15% x 5 % results in a cost of about 0.75%. If we double we have good chance to win extra two points in about 30% of all games x 80% gammon = 24% gammon x 10% extra gain from additional 2 points. This brings extra 2.4% for the price of 0.75%. That’s a good deal. Such estimates are very inaccurate because they are based on assumptions and because they do not consider all possibilities like white losing a single game after Neil hits on the 4 point. But one should know how the odds multiply in principle in order to find a result like the first sentence over the board.


Neil Kazaross takes.

Great job by the USBGF Members finding this desperation double. I would not have have made the previous play if I’d thought that the majority would vote to cube. Of course I must take as I will win this game almost every time I am not hit.



USBGF Members: 42 b/21*
Neil Kazaross: 64 no play


Today’s vote:

is Neil Kazaross

score: 9
pip: 81
                         
11 point match
                          pip: 130
score: 2

is USBGF Members
XGID=aB-BBBC-------aa---cBAcbdA:1:-1:1:42:2:9:0:11:10
to play 42

eXtreme Gammon Version: 2.10

Comments

  1. Chuck Bower says:

    We only have two plays to consider after the forced entry 25/21: 20/18 and 6/4. Every one of Neil’s eleven entering numbers hits if we play 20/18 vs. none after 6/4. That is the downside. If he fans we go from 31 hits (for us) to 36 (gain of 5). This doesn’t sound like good enough odds for for the loose play.

    25/21, 6/4

  2. Todd Porter Todd Porter says:

    LOL Love Neil’s comment, “I would not have have made the previous play if I’d thought that the majority would vote to cube.”

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