I have all day to get my back checker out

[Tim Chow]

XGID=aBB-BBCBA-----a--cbcc-b-A-:0:0:1:00:0:0:1:0:10

X:Player 1 O:Player 2
Score is X:0 O:0. Money session, Jacoby
+13-14-15-16-17-18------19-20-21-22-23-24-+
| O O O | | O O O X |
| O O | | O O O |
| O | | O O |
| | | |
| | | |
| |BAR| |
| | O | |
| | | |
| | | X |
| X | | X X X X X |
| X X | | X X X X X |
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pipcount X: 88 O: 113 X-O: 0-0
Cube : 1
X on roll, cube action

---
Tim Chow

[Bradley K. Sherman]

Tim Chow <tchow...@yahoo.com> wrote:
>Score is X:0 O:0. Money session, Jacoby
> +13-14-15-16-17-18------19-20-21-22-23-24-+
> | O O O | | O O O X |
> | O O | | O O O |
> | O | | O O |
> | | | |
> | | | |
> | |BAR| |
> | | O | |
> | | | |
> | | | X |
> | X | | X X X X X |
> | X X | | X X X X X |
> +12-11-10--9--8--7-------6--5--4--3--2--1-+

> X:88 O:113, Cube:1, X on roll, cube action

Oh, criminy. I have no idea. If I were O in this
position I would pass because of the gammon possibilities,
so my complete guess is:
Double/Pass

--bks

[badgolferman]

Double / Pass

[crf]

X needs to escape that back man pretty soon before his home board crunches. And unfortunately, that requires many of the same numbers he could use to close O out. Assuming any 3s (and 12) get used to move up, only 22 44 and 45 close O out. That leaves a lot of sequences that make it hard for X.

D/T, maybe not even a double?

[Freeven]

Can O take? I think so, but I'm not sure, so that settles the doubling
side of it.

Why do I think O can take? Because he usually gets a couple of chances
to roll a 3. X isn't a favorite to either make his 3pt or escape his
back checker on any given roll, and he needs some of the same rolls to
do both. If O enters and X hits loose, O has a chance to send a second
checker back and become the favorite. Most of X's 4s, 5s, and 6s force
him to play past the gap he wants to fill, which means things often get
easier for O if he can survive the immediate exchange.

As a sanity check, let me take a stab at the numbers. This isn't
something I'm good at, and this is a tough position, but I'd guess that
X wins 25% gammons and O wins 8% gammons. O's TP is about 22%, plus half
the difference between the two: 22 + .5(25-8) = 30.5%. Can O win more
that often? It looks close to me, but I think he can.

D/T

[peps...@gmail.com]

Big hold. Only massive market losers are 53 and 63. X will be lucky to closeout without leaving a shot particularly with 53 being duplicated. X doesn't have enough of a pip lead for a gammon, and the title of the thread is a joke -- X is running out of time.
A key point, which explains the hold, is that closeout rolls like 54 do not lose market because it's so easy for X to bust afterwards.

This does not solve the problem, however. With such a clear hold, O needs to consider beavering.
I think it's close to a beaver, but that's unlikely because X is so much more likely to get a gammon than O.

ND/T. Second choice would be a beaver.

Paul Epstein

[Walt]

On 5/3/2013 7:21 PM, Tim Chow wrote:

Both sides need a 3, and whoever rolls one first is the favorite, with X
being a bigger favorite.

X is on roll, so he has first crack at it. X also has some numbers that
take away O's chance to roll a 3 by closing the bar.

If X rolls a 3, I think he's lost his market, so with 13 market losers
it might be a cube. OTOH, there are lots of sequences where the cube
come flying back. I'd definitely cube this at a match score where the
cube would be dead, but here I think the recubes are too unappetizing.

ND/T

//Walt

[Walt]

On 5/4/2013 7:21 AM, Walt wrote:
> On 5/3/2013 7:21 PM, Tim Chow wrote:
>> XGID=aBB-BBCBA-----a--cbcc-b-A-:0:0:1:00:0:0:1:0:10

>

> Both sides need a 3, and whoever rolls one first is the favorite, with X
> being a bigger favorite.
>
> X is on roll, so he has first crack at it. X also has some numbers that
> take away O's chance to roll a 3 by closing the bar.
>
> If X rolls a 3, I think he's lost his market, so with 13 market losers
> it might be a cube. OTOH, there are lots of sequences where the cube
> come flying back. I'd definitely cube this at a match score where the
> cube would be dead, but here I think the recubes are too unappetizing.
>
> ND/T

Hmmm... I didn't say anything about the take, since it seemed obvious.
Now that I've read other replies I see that some think this is a pass.
There are far too many ways for this to go wrong for X in a hurry to
pass this. Two successive rolls of non-three and X's board begins to
crunch - this will happen about 50% of the time. Look at how big
doubles destroys X. Plus, I don't see that many gammons.

//Walt

[Tim Chow]

There's a famous poem by Longfellow that goes like this:

There was a little girl
Who had a little curl
Right in the middle of her forehead.
And when she was good
She was very, very good
But when she was bad
She was horrid!

This position, like many priming battles, has the feature that X's
good rolls are very, very good, but X's bad rolls are horrid. The
combination of these two extremes makes the cube action difficult to
assess. If you considered only X's good rolls or if you considered
only X's bad rolls, then the first lesson to learn is that both halves
of the equation have to be considered, particularly in a "high-
variance" position like this one.

One feature to note that wasn't mentioned explicitly by anyone is O's
outfield blot. That will increase X's gammons somewhat, though not by
a huge amount since X won't have a lot of time to sit around hoping to
hit that blot once he escapes.

Paradoxically, in most chouettes, the doubling decision is (or should
be) easy, precisely because (as we saw from the responses) the
reaction is likely to be mixed, and this will most likely more than
compensate for any technical equity that doubling might theoretically
lose you.

=======
Rollout
=======

Analyzed in Rollout
No Double
Player Winning Chances: 60.86% (G: 18.61% B: 0.15%)
Opponent Winning Chances: 39.14% (G: 4.98% B: 0.18%)
Double/Take
Player Winning Chances: 60.19% (G: 20.20% B: 0.17%)
Opponent Winning Chances: 39.81% (G: 4.70% B: 0.16%)

Cubeful Equities:
No Double: +0.284 (-0.111)
Double/Take: +0.395
Double/Drop: +1.000 (+0.605)

Best Cube action: Double / Take

Rollout
1296 Games rolled with Variance Reduction.
Dice Seed: 2
Moves and cube decisions: 3 ply
Confidence No Double: ±0.011 (+0.272<E<+0.295)
Confidence Double: ±0.018 (+0.377<E<+0.413)

eXtreme Gammon Version: 1.21