Tuition time

[peps...@gmail.com]

Below, I played 13/7(2).
Why is the difference between XG's play and my play like the difference
between freshly squeezed orange juice and the syrupy orange-flavoured
squash that I had to make do with as a child?

Thanks for enlightening me.

Paul

XGID=-ADAb-C-B-B-aB----bbbcba--:1:-1:1:33:0:1:3:0:10
X:Daniel O:eXtremeGammon

Score is X:0 O:1. Unlimited Game, Jacoby Beaver
+13-14-15-16-17-18------19-20-21-22-23-24-+
| X O | | O O O O O | +---+
| X O | | O O O O | | 2 |
| | | O | +---+
| | | |
| | | |
| |BAR| |
| | | |
| | | X |
| | | X X |
| X X | | X O X |
| O X X | | X O X X X |
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 92 O: 111 X-O: 0-1
Cube: 2, O own cube
X to play 33



1. XG Roller+ 13/10(2) 8/5(2) eq:+0.402
Player: 73.56% (G:2.96% B:0.03%)
Opponent: 26.44% (G:2.33% B:0.06%)

2. XG Roller+ 13/7(2) eq:+0.249 (-0.152)
Player: 67.17% (G:1.71% B:0.02%)
Opponent: 32.83% (G:2.65% B:0.05%)

3. 3-ply 10/7(2) 8/5(2) eq:+0.267 (-0.134)
Player: 68.32% (G:4.25% B:0.03%)
Opponent: 31.68% (G:2.97% B:0.06%)

4. 1-ply 13/10 8/5(2) 6/3 eq:-0.213 (-0.615)
Player: 50.26% (G:4.14% B:0.06%)
Opponent: 49.74% (G:8.20% B:0.28%)

5. 1-ply 8/2(2) eq:-0.258 (-0.659)
Player: 50.21% (G:1.88% B:0.02%)
Opponent: 49.79% (G:10.32% B:0.21%)


eXtreme Gammon Version: 2.10

[Timothy Chow]

On 8/14/2022 2:44 PM, peps...@gmail.com wrote:
> XGID=-ADAb-C-B-B-aB----bbbcba--:1:-1:1:33:0:1:3:0:10
> X:Daniel O:eXtremeGammon
>
> Score is X:0 O:1. Unlimited Game, Jacoby Beaver
> +13-14-15-16-17-18------19-20-21-22-23-24-+
> | X O | | O O O O O | +---+
> | X O | | O O O O | | 2 |
> | | | O | +---+
> | | | |
> | | | |
> | |BAR| |
> | | | |
> | | | X |
> | | | X X |
> | X X | | X O X |
> | O X X | | X O X X X |
> +12-11-10--9--8--7-------6--5--4--3--2--1-+
> Pip count X: 92 O: 111 X-O: 0-1
> Cube: 2, O own cube
> X to play 33
>
>
>
> 1. XG Roller+ 13/10(2) 8/5(2) eq:+0.402
> Player: 73.56% (G:2.96% B:0.03%)
> Opponent: 26.44% (G:2.33% B:0.06%)
>
> 2. XG Roller+ 13/7(2) eq:+0.249 (-0.152)
> Player: 67.17% (G:1.71% B:0.02%)
> Opponent: 32.83% (G:2.65% B:0.05%)

In Michy's article, "I Mourn for Falafel," he talks about the "island"
concept, where all your outfield points are stripped.

http://www.world-backgammon-association.com/attachments/article/131/I-Mourn-for-Falafel.pdf

If you play 13/7(2) then you retain the inflexible "island" formation.
If you play 13/10(2) 8/5(2), then you create useful spares on your 10pt.
You might worry that it will be hard to clear the 10pt safely, and that
is indeed a concern; however, by the time you have to break the 10pt,
your opponent may have already been forced to break anchor, or you may
have had a chance to roll doublets again.

---
Tim Chow

[peps...@gmail.com]

Thanks for your analysis and the article.
In the final position, I think 13/11 5/1 is hugely motivated by the opponent's stripped midpoint which
means that, if the opponent hits with an ace, we will usually get an enormous number of returns.

If we variantize by non-stripping the opponent's midpoint, moving an opponent's checker from their 8 point to their midpoint, 13/11 5/1 might no longer be a weekend in Paris,
despite the deislandisation of the play.

Paul

[Stick Rice]

It's not just this though...it's making the 5pt/landing point in conjunction with it. If the 5pt was already made then 7(2) would be correct.

Stick