Post-blitz cube 1

[Tim Chow]

Two defects in my blitzing game are: (1) cashing when too good; (2) not playing the checkers aggressively enough. Now that I've started correcting these defects, a new challenge has arisen: When I'm blitzing, sometimes the opponent manages to hit back and/or anchor. If I've been playing on, I now have to think about the cube action. I find these cubes very difficult. They can range anywhere from ND/beaver to TG/pass. I also have seldom seen them discussed in books and articles. My next series of problems will give some examples. Ultimately, I think it would be valuable to develop some reference positions, but at this stage I'm still just trying to collect examples.

XGID=aBBB-aBAAA--d----d-eA-A-AA:0:0:1:00:0:0:0:7:10

X:Player 1 O:Player 2
Score is X:0 O:0 7 pt.(s) match.
+13-14-15-16-17-18------19-20-21-22-23-24-+
| O | | O X X X |
| O | | O |
| O | | O |
| O | | O |
| | X | O |
| |BAR| |
| | O | |
| O | | |
| O | | |
| O | | X X X X |
| O X X X | | X O X X X |
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 139 O: 159 X-O: 0-0/7
Cube: 1
X on roll, cube action

---
Tim Chow

[badgolferman]

TG/Pass

[smcrtorchs]

O will anchor next turn if X rolls a 6 or 51 and O rolls a 5 or a 41. This means 0.36*0.36 = around 13%. But he should have more chances to anchor in the future at the 5 or the 4. However X should be a favorite here, but if we judge from this immediate 13% that O has then X chances should be at low 60's. Probably 60-62. I think that X should be winning a little over 50% gammons when he wins a game. So let's say 35% gammons. If X's winning chances are that low, then cube revig is higher for O and all the facts above should make it a double /take.

[Tim Chow]

XGID=aBBB-aBAAA--d----d-eA-A-AA:0:0:1:00:0:0:0:7:10

X:Player 1 O:Player 2
Score is X:0 O:0 7 pt.(s) match.
+13-14-15-16-17-18------19-20-21-22-23-24-+
| O | | O X X X |
| O | | O |
| O | | O |
| O | | O |
| | X | O |
| |BAR| |
| | O | |
| O | | |
| O | | |
| O | | X X X X |
| O X X X | | X O X X X |
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 139 O: 159 X-O: 0-0/7
Cube: 1
X on roll, cube action

I'm not going to offer much commentary because I don't (yet) understand these sorts of positions very well. According to the rollout, this is a huge pass but also a huge double. In the variant position, I've advanced one of X's back checkers to the point where the rollout declares X to be too good.

Analyzed in Rollout
No double
Player Winning Chances: 68.50% (G:47.84% B:0.40%)
Opponent Winning Chances: 31.50% (G:8.23% B:0.63%)
Double/Take
Player Winning Chances: 68.59% (G:48.29% B:0.50%)
Opponent Winning Chances: 31.41% (G:8.32% B:1.01%)

Cubeful Equities:
No double: +0.832 (-0.168)
Double/Take: +1.368 (+0.368)
Double/Pass: +1.000

Best Cube action: Double / Pass

Rollout:
1296 Games rolled with Variance Reduction.
Dice Seed: 271828
Moves: 3-ply, cube decisions: XG Roller
Confidence No Double: ± 0.013 (+0.819..+0.845)
Confidence Double: ± 0.018 (+1.350..+1.385)

=======
Variant
=======

XGID=aBBB-aBAAA--dA---d-eA---AA:0:0:1:00:0:0:0:7:10

X:Player 1 O:Player 2
Score is X:0 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 |
| O | | O |
| O | | O |
| | X | O |
| |BAR| |
| | O | |
| O | | |
| O | | |
| O | | X X X X |
| O X X X | | X O X X X |
+12-11-10--9--8--7-------6--5--4--3--2--1-+

Pip count X: 130 O: 159 X-O: 0-0/7

Cube: 1
X on roll, cube action

Analyzed in Rollout
No double
Player Winning Chances: 73.29% (G:53.48% B:0.43%)
Opponent Winning Chances: 26.71% (G:6.44% B:0.55%)
Double/Take
Player Winning Chances: 73.41% (G:53.88% B:0.36%)
Opponent Winning Chances: 26.59% (G:6.57% B:0.73%)

Cubeful Equities:
No double: +1.030
Double/Take: +1.752 (+0.722)
Double/Pass: +1.000 (-0.030)

Best Cube action: Too good to double / Pass
Percentage of wrong take needed to make the double decision right: 4.0%

Rollout:
1296 Games rolled with Variance Reduction.
Dice Seed: 271828
Moves: 3-ply, cube decisions: XG Roller
Confidence No Double: ± 0.013 (+1.017..+1.042)
Confidence Double: ± 0.018 (+1.734..+1.769)

eXtreme Gammon Version: 2.10, MET: Kazaross XG2

---
Tim Chow

[Bradley K. Sherman]

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

> X:139 O:159, Cube:1, X on roll, cube action?

TG/Drop

--bks

[Walt]

On 2/25/2014 12:35 PM, Tim Chow wrote:

> XGID=aBBB-aBAAA--d----d-eA-A-AA:0:0:1:00:0:0:0:7:10
>
> X:Player 1 O:Player 2
> Score is X:0 O:0 7 pt.(s) match.
> +13-14-15-16-17-18------19-20-21-22-23-24-+
> | O | | O X X X |
> | O | | O |
> | O | | O |
> | O | | O |
> | | X | O |
> | |BAR| |
> | | O | |
> | O | | |
> | O | | |
> | O | | X X X X |
> | O X X X | | X O X X X |
> +12-11-10--9--8--7-------6--5--4--3--2--1-+
> Pip count X: 139 O: 159 X-O: 0-0/7
> Cube: 1
> X on roll, cube action

I see that a rollout has already been posted, but I'll comment anyway
before reading it.

O's structure is awful, with basically no development. OTOH, if she can
anchor on X's 5 point she'll definitely be in it for a while.
meanwhile, X has a serious problem with premature burial and no chance
at containment should O enter.

I'd cube this one, mainly because I can't decide if it's a take or not.
It's probably a pass due to the gammon risks but I'm not sure. As X,
I'm happy to take a point now and equally happy to try for a gammon with
the cube at 2.

D/P.

--
//Walt