XGID=-b----EBB---cD--ac-d-b--B-:0:0:1:61:0:0:0:0:10

X:Player 1 O:Player 2
Score is X:0 O:0. Unlimited Game
+13-14-15-16-17-18------19-20-21-22-23-24-+
| X O O | | O O X |
| X O | | O O X |
| X O | | O |
| X | | O |
| | | |
| |BAR| |
| | | X |
| | | X |
| O | | X |
| O X X | | X O |
| O X X | | X O |
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 160 O: 152 X-O: 0-0
Cube: 1
X to play 61

---
Tim Chow

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

21 Mayıs 2022 Cumartesi tarihinde saat 18:21:57 UTC+3 itibarıyla Tim Chow şunları yazdı:

XGID=-b----EBB---cD--ac-d-b--B-:0:0:1:61:0:0:0:0:10

X:Player 1 O:Player 2
Score is X:0 O:0. Unlimited Game
+13-14-15-16-17-18------19-20-21-22-23-24-+
| X O O | | O O X |
| X O | | O O X |
| X O | | O |
| X | | O |
| | | |
| |BAR| |
| | | X |
| | | X |
| O | | X |
| O X X | | X O |
| O X X | | X O |
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 160 O: 152 X-O: 0-0
Cube: 1
X to play 61

---
Tim Chow

Making the 5 point after making the bar point is a very powerful move. Especially if the opponent hasn't touched their back checkers yet. And a stripped eight point always forces you to use checkers on the 6 point.
Moreover, in this position, something has to be done to distract the opponent because he has very strong shots. I prefer the slot game. 13/7 6/5

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

XGID=-b----EBB---cD--ac-d-b--B-:0:0:1:61:0:0:0:0:10

X:Player 1 O:Player 2
Score is X:0 O:0. Unlimited Game
+13-14-15-16-17-18------19-20-21-22-23-24-+
| X O O | | O O X |
| X O | | O O X |
| X O | | O |
| X | | O |
| | | |
| |BAR| |
| | | X |
| | | X |
| O | | X |
| O X X | | X O |
| O X X | | X O |
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 160 O: 152 X-O: 0-0
Cube: 1
X to play 61

Slotting this early in the game when your opponent has made her 5pt
or 4pt, and you have not made any new home-board points, is not usually recommended by XG. Usually you want to split to avoid getting primed.
However, X is already somewhat behind in the pip count, and O has ten
checkers in the zone that can attack as well as prime. X does have a
heavy 6pt stack and making a solid four-prime would certainly be a
significant positional improvement.

At first I thought that duplication of O's 4s played an important
role, but after fiddling around with a few variants, I concluded
that this wasn't a major factor.

1. Rollout¹ 13/7 6/5 eq:-0.192
Player: 46.35% (G:13.43% B:0.69%)
Opponent: 53.65% (G:18.73% B:1.29%)
Confidence: ±0.008 (-0.199..-0.184) - [100.0%]

2. Rollout¹ 24/23 13/7 eq:-0.264 (-0.073)
Player: 44.73% (G:12.39% B:0.65%)
Opponent: 55.27% (G:20.32% B:0.79%)
Confidence: ±0.007 (-0.272..-0.257) - [0.0%]

¹ 5184 Games rolled with Variance Reduction.
Dice Seed: 271828
Moves: 3-ply, cube decisions: XG Roller

eXtreme Gammon Version: 2.19.207.pre-release

---
Tim Chow

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

XGID=-dBBB-BD-----A--bb-cbB-b--:1:-1:1:42:0:0:0:0:10

Score is X:0 O:0. Unlimited Game
+13-14-15-16-17-18------19-20-21-22-23-24-+
| X O O | | O O X O | +---+
| O O | | O O X O | | 2 |
| | | O | +---+
| | | |
| | | |
| |BAR| |
| | | |
| X | | O |
| X | | O |
| X | | X X X X O |
| X | | X X X X O |
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 113 O: 162 X-O: 0-0
Cube: 2, O own cube
X to play 42

---
Tim Chow

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

On Wednesday, March 22, 2023 at 9:38:13 AM UTC-4, Timothy Chow wrote:

XGID=-dBBB-BD-----A--bb-cbB-b--:1:-1:1:42:0:0:0:0:10

Score is X:0 O:0. Unlimited Game
+13-14-15-16-17-18------19-20-21-22-23-24-+
| X O O | | O O X O | +---+
| O O | | O O X O | | 2 |
| | | O | +---+
| | | |
| | | |
| |BAR| |
| | | |
| X | | O |
| X | | O |
| X | | X X X X O |
| X | | X X X X O |
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 113 O: 162 X-O: 0-0
Cube: 2, O own cube
X to play 42

---
Tim Chow

I would play 13/11 7/3 to cover 24/20, -/- played by O's back checker. O's 64 would hit us, but not much lost in the transaction. O's position is so tenuous that I don't think slotting is useful. I don't want to waste time on the bar and miss the
opportunity to take advantage of O's breaking up.
Bob

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

XGID=-dBBB-BD-----A--bb-cbB-b--:1:-1:1:42:0:0:0:0:10

Score is X:0 O:0. Unlimited Game
+13-14-15-16-17-18------19-20-21-22-23-24-+
| X O O | | O O X O | +---+
| O O | | O O X O | | 2 |
| | | O | +---+
| | | |
| | | |
| |BAR| |
| | | |
| X | | O |
| X | | O |
| X | | X X X X O |
| X | | X X X X O |
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 113 O: 162 X-O: 0-0
Cube: 2, O own cube
X to play 42

The trouble with not slotting is that the alternatives are destructive,
either stacking up another checker on the bar point, or putting a
checker out of play with 7/3. It might seem that X has a big enough
advantage that he should be playing safe, but making his 5pt would be
a big improvement, while getting hit is not irrecoverable.

If the roll were 21 instead of 42 (see variant), then the safe play of
13/11 7/6 would be a viable candidate (though XG still slightly prefers slotting).

1. Rollout¹ 13/9 7/5 eq:+0.958
Player: 80.17% (G:42.64% B:5.08%)
Opponent: 19.83% (G:4.30% B:0.20%)
Confidence: ±0.008 (+0.950..+0.967) - [100.0%]

2. Rollout¹ 13/11 7/3 eq:+0.753 (-0.205)
Player: 74.81% (G:36.24% B:4.45%)
Opponent: 25.19% (G:5.05% B:0.20%)
Confidence: ±0.009 (+0.744..+0.762) - [0.0%]

3. Rollout¹ 13/7 eq:+0.736 (-0.222)
Player: 74.87% (G:34.86% B:4.14%)
Opponent: 25.13% (G:4.82% B:0.15%)
Confidence: ±0.009 (+0.727..+0.745) - [0.0%]

4. Rollout¹ 7/5 7/3 eq:+0.705 (-0.253)
Player: 73.63% (G:36.18% B:4.36%)
Opponent: 26.37% (G:6.42% B:0.34%)
Confidence: ±0.008 (+0.697..+0.714) - [0.0%]

¹ 1296 Games rolled with Variance Reduction.
Dice Seed: 271828
Moves: 3-ply, cube decisions: XG Roller

eXtreme Gammon Version: 2.19.211.pre-release

-------
Variant
-------

XGID=-dBBB-BD-----A--bb-cbB-b--:1:-1:1:12:0:0:0:0:10

Score is X:0 O:0. Unlimited Game
+13-14-15-16-17-18------19-20-21-22-23-24-+
| X O O | | O O X O | +---+
| O O | | O O X O | | 2 |
| | | O | +---+
| | | |
| | | |
| |BAR| |
| | | |
| X | | O |
| X | | O |
| X | | X X X X O |
| X | | X X X X O |
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 113 O: 162 X-O: 0-0
Cube: 2, O own cube
X to play 12

1. Rollout¹ 7/6 7/5 eq:+0.961
Player: 80.47% (G:42.34% B:4.84%)
Opponent: 19.53% (G:4.56% B:0.25%)
Confidence: ±0.008 (+0.953..+0.969) - [99.9%]

2. Rollout¹ 13/11 7/6 eq:+0.943 (-0.018)
Player: 80.08% (G:41.04% B:5.00%)
Opponent: 19.92% (G:3.82% B:0.16%)
Confidence: ±0.008 (+0.934..+0.951) - [0.1%]

3. Rollout¹ 13/12 7/5 eq:+0.938 (-0.023)
Player: 80.00% (G:41.86% B:4.68%)
Opponent: 20.00% (G:4.63% B:0.23%)
Confidence: ±0.009 (+0.929..+0.947) - [0.0%]

4. Rollout¹ 13/10 eq:+0.859 (-0.102)
Player: 78.12% (G:38.46% B:4.54%)
Opponent: 21.88% (G:4.38% B:0.19%)
Confidence: ±0.008 (+0.851..+0.867) - [0.0%]

¹ 1296 Games rolled with Variance Reduction.
Dice Seed: 271828
Moves: 3-ply, cube decisions: XG Roller

eXtreme Gammon Version: 2.19.211.pre-release

---
Tim Chow

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

On 2023-03-24, Timothy Chow <[email protected]> wrote:

XGID=-dBBB-BD-----A--bb-cbB-b--:1:-1:1:42:0:0:0:0:10

Score is X:0 O:0. Unlimited Game
+13-14-15-16-17-18------19-20-21-22-23-24-+
| X O O | | O O X O | +---+
| O O | | O O X O | | 2 |
| | | O | +---+
| | | |
| | | |
| |BAR| |
| | | |
| X | | O |
| X | | O |
| X | | X X X X O |
| X | | X X X X O |
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 113 O: 162 X-O: 0-0
Cube: 2, O own cube
X to play 42

The trouble with not slotting is that the alternatives are destructive, either stacking up another checker on the bar point, or putting a
checker out of play with 7/3. It might seem that X has a big enough advantage that he should be playing safe, but making his 5pt would be
a big improvement, while getting hit is not irrecoverable.

I'm not sure "getting hit is not irrecoverable" (while certainly true)
is the most accurate reason to split.

The most important point is probably that a 4 for the opponent is a very
good roll whether it hits a slot or not. The slot is just not that
costly when it fails.

If the roll were 21 instead of 42 (see variant),

Then X has more builders aimed at the 5 point and retains some outfield
control so most non-hitting 4s are not as strong than after 42.

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

On March 29, 2023 at 4:30:38 PM UTC-6, Philippe Michel wrote:

On 2023-03-24, Timothy Chow <[email protected]> wrote:

XGID=-dBBB-BD-----A--bb-cbB-b--:1:-1:1:42:0:0:0:0:10
X to play 42

Since I found this position interesting and used
it in another thread, I may as well comment on it.

https://groups.google.com/g/rec.games.backgammon/c/Z1QsqqGbTsw/m/x-wV5kisBAAJ

..... or putting a checker out of play with 7/3.

The 4th checker on the 7-point is already the
most useless one anyway and after 7/3 it's
not completely out of play either.

It might seem that X has a big enough
advantage that he should be playing safe,

Not just it seems so but it is so.

making his 5pt would be a big improvement,

There is no need to rush to make it. With O's
4 checkers on X's 1-point, that can wait.

I'm not sure "getting hit is not irrecoverable"
..... is the most accurate reason to split.
The slot is just not that costly when it fails.

Hard to understand why you are objecting to
Tim and what you are arguing for instead...?

Anyway, I think Zimmer got this one right. I
would play 13/11 7/3 also and the "clinical
rollouts" I have done at the link above show
that it's slightly better than 13/9 7/5 (or at
least not any worse).

MK

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