I don't post that many score-based cube actions, but I've
saved up a few interesting ones that I plan to post over the
next few days. Here's the first one.

XGID=bB-BB-B-----dE---d-e----B-:0:0:1:00:4:0:0:7:10

X:Player 1 O:Player 2
Score is X:4 O:0 7 pt.(s) match.
+13-14-15-16-17-18------19-20-21-22-23-24-+
| X O | | O X |
| X O | | O X |
| X O | | O |
| X O | | O |
| X | | O |
| |BAR| |
| | O | |
| O | O | |
| O | | |
| O | | X X X X |
| O | | X X X X |
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 141 O: 164 X-O: 4-0/7
Cube: 1
X on roll, cube action

---
Tim Chow

On 9/22/2022 8:07 AM, Timothy Chow wrote:
> I don't post that many score-based cube actions, but I've
> saved up a few interesting ones that I plan to post over the
> next few days.  Here's the first one.
>
> XGID=bB-BB-B-----dE---d-e----B-:0:0:1:00:4:0:0:7:10
>
> X:Player 1   O:Player 2
> Score is X:4 O:0 7 pt.(s) match.
>  +13-14-15-16-17-18------19-20-21-22-23-24-+
>  | X           O    |   | O              X |
>  | X           O    |   | O              X |
>  | X           O    |   | O                |
>  | X           O    |   | O                |
>  | X                |   | O                |
>  |                  |BAR|                  |
>  |                  | O |                  |
>  | O                | O |                  |
>  | O                |   |                  |
>  | O                |   | X     X  X     X |
>  | O                |   | X     X  X     X |
>  +12-11-10--9--8--7-------6--5--4--3--2--1-+
> Pip count  X: 141  O: 164 X-O: 4-0/7
> Cube: 1
> X on roll, cube action

O's takepoint is lower than usual due to the score, at about 18%.

X has a formidable four point board , but no other checker in the zone,
but O has only four shakes that enter both so X will most likely have
ten in the zone with a checker on the bar next roll. Which is to say
things are not likely to improve for O right away unless she rolls 22 or
55, and even then X has a commanding lead.

I don't see how O can take this, although I do recall someone saying
that any time you hold both ace points it's a pass which is definitely
an overstatement as applied to this position, but maybe it's enough of a
liability for O to eke out a take here.

I'd take a shake. We probably have a cash next roll unless O rolls 55,
if that's right then we can't lose and have some gammon chances so roll.

TG/P.

XGID=bB-BB-B-----dE---d-e----B-:0:0:1:00:4:0:0:7:10

X:Player 1 O:Player 2
Score is X:4 O:0 7 pt.(s) match.
+13-14-15-16-17-18------19-20-21-22-23-24-+
| X O | | O X |
| X O | | O X |
| X O | | O |
| X O | | O |
| X | | O |
| |BAR| |
| | O | |
| O | O | |
| O | | |
| O | | X X X X |
| O | | X X X X |
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 141 O: 164 X-O: 4-0/7
Cube: 1
X on roll, cube action

Though I frequently complain about Stick's DMP rule, there is one
rule that I learned from Stick that I have found to be extremely
useful and reliable. At 3-away/many-away, the 3-away player should
not double in gammonish positions. The reason is that such positions
are usually either too good or not good enough.

Stick says that for the purposes of this rule, "many" should be defined
as 8 or more, with 7 being borderline. My experience is that it is a
reliable rule for 7 or more, with 6 being borderline, but this is
splitting hairs.

I have, however, found that there is one important class of exceptions,
when both of the following conditions are satisfied:

1. The 3-away player wins a lot of gammons but does not lose many
gammons (let's say the 3-away player loses at most 5% gammons).

2. The many-away player is very close to the take/pass borderline.

In such situations, the 3-away player will usually have a big double.

When one tries to apply this rule OTB, the tough part is usually #2,
since it is not easy to assess when the many-away player is close to
the take/pass borderline. I think that the only way to acquire this
ability is through experience. Typically, the many-away player will
win about 25% of the time.

The position here is an excellent illustration of this exceptional case.
This is a highly gammonish position so you might think, following
Stick's rule, that it would not be a double for the 3-away player. But
the rollout says it's a double---the 3-away player loses only about 5%
gammons, and the take/pass decision is what Paul might call "ultra-
marginal."

However, if for example you bring down an extra checker from the
midpoint, you'll find that it slides into TG territory.

Analyzed in Rollout
No double
Player Winning Chances: 74.89% (G:52.92% B:1.23%)
Opponent Winning Chances: 25.11% (G:5.49% B:0.29%)
Double/Take
Player Winning Chances: 74.93% (G:54.68% B:1.87%)
Opponent Winning Chances: 25.07% (G:5.86% B:0.56%)

Cubeful Equities:
No double: +0.917 (-0.081)
Double/Take: +0.998
Double/Pass: +1.000 (+0.002)

Best Cube action: Double / Take

Rollout:
5184 Games rolled with Variance Reduction.
Dice Seed: 271828
Moves: 3-ply, cube decisions: XG Roller
Confidence No Double: ± 0.006 (+0.911..+0.924)
Confidence Double: ± 0.011 (+0.987..+1.009)

eXtreme Gammon Version: 2.19.207.pre-release, MET: Kazaross XG2

---
Tim Chow

Stick says that for the purposes of this rule, "many" should be defined
as 8 or more, with 7 being borderline. My experience is that it is a
reliable rule for 7 or more, with 6 being borderline, but this is
splitting hairs.

> Tim Chow

Stick has always said 3a 7a or greater is the rule and that it can be used (cautiously) with 3a 6a. I don't ever even remember breathing about 3a 8a specifically.

Stick

On 9/25/2022 8:14 PM, Stick Rice wrote:
> Stick says that for the purposes of this rule, "many" should be defined
> as 8 or more, with 7 being borderline. My experience is that it is a
> reliable rule for 7 or more, with 6 being borderline, but this is
> splitting hairs.
>
>> Tim Chow
>
> Stick has always said 3a 7a or greater is the rule and that it can be used (cautiously) with 3a 6a. I don't ever even remember breathing about 3a 8a specifically.

Sorry, I was relying on my memory of your comment at the end of the
BGO article below, where you mention 3a 8a and higher. But now that
I look it up, I see that you say 3a 7a is the rule.

http://www.bgonline.org/forums/webbbs_config.pl?read=195914

---
Tim Chow