Below, I actually lost 0.537 equity.
All I was trying to do was anchor on the opponent's 4 point for solidity.
Why is this a worse idea than putting lumps of chocolate
into a Margherita Pizza?

Thanks for your help.

Paul

XGID=-----BCBC---bB---dcd-A-Bb-:0:0:1:52:5:0:3:0:10
X:Daniel O:eXtremeGammon

Score is X:5 O:0. Unlimited Game, Jacoby Beaver
+13-14-15-16-17-18------19-20-21-22-23-24-+
| X O O | | O X X O |
| X O O | | O X O |
| O O | | O |
| O | | O |
| | | |
| |BAR| |
| | | |
| | | |
| X | | X |
| 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: 159 O: 105 X-O: 5-0
Cube: 1
X to play 52

1. XG Roller+ 21/16 6/4 eq:-0.377
Player: 40.22% (G:4.84% B:0.13%)
Opponent: 59.78% (G:11.29% B:0.31%)

2. XG Roller+ 23/21 8/3 eq:-0.913 (-0.537)
Player: 28.58% (G:3.71% B:0.11%)
Opponent: 71.42% (G:16.33% B:0.15%)

3. 4-ply 21/16 8/6 eq:-0.454 (-0.077)
Player: 38.39% (G:4.83% B:0.07%)
Opponent: 61.61% (G:13.16% B:0.34%)

4. 4-ply 8/3 6/4 eq:-0.507 (-0.131)
Player: 38.69% (G:5.56% B:0.11%)
Opponent: 61.31% (G:18.63% B:0.66%)

5. 3-ply 21/14 eq:-0.524 (-0.147)
Player: 36.28% (G:4.17% B:0.12%)
Opponent: 63.72% (G:12.73% B:0.30%)


eXtreme Gammon Version: 2.10

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

On 5/4/2022 11:30 AM, [email protected] wrote:

Below, I actually lost 0.537 equity.
All I was trying to do was anchor on the opponent's 4 point for solidity.

You're massively behind in the pip count so you have to hit a shot,
and so you have to stay back for more contact.

I'm reminded of the position below from Mike Corbett's book, "Backgammon Problems." He makes the following rather brutal comment: "If you
advocate making the advanced anchor, then whatever division you're
playing in, demote yourself to the next lower one." He goes on to
explain, "X must capture one of O's checkers to win, and the two point
anchor rates to generate significantly more shots than the four point
with a blot on the two point."

XGID=----BBCAAA---Ba-cbbbcA-Bb-:0:0:1:62:0:0:3:0:10

X:Player 1 O:Player 2
Score is X:0 O:0. Unlimited Game, Jacoby Beaver
+13-14-15-16-17-18------19-20-21-22-23-24-+
| X O O O O | | O O X X O |
| X O O O | | O O X O |
| O | | O |
| | | |
| | | |
| |BAR| |
| | | |
| | | |
| | | X |
| | | X X X |
| X X X | | X X X |
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 153 O: 97 X-O: 0-0
Cube: 1
X to play 62

1. XG Roller+ 21/15 9/7 eq:-0.770
Player: 31.85% (G:3.35% B:0.11%)
Opponent: 68.15% (G:15.55% B:0.56%)

2. XG Roller+ 21/15 13/11 eq:-0.785 (-0.015)
Player: 31.61% (G:3.44% B:0.12%)
Opponent: 68.39% (G:16.20% B:0.68%)

3. XG Roller+ 21/13 eq:-0.824 (-0.054)
Player: 29.79% (G:3.14% B:0.11%)
Opponent: 70.21% (G:13.18% B:0.51%)

eXtreme Gammon Version: 2.19.207.pre-release

---
Tim Chow

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

Whoops...I neglected to post any bot info for making the advanced
anchor. See below. I have given X the cube, because with the cube
in the center, XG says that X has to pass O's double if X plays
23/21 13/7. If the cube were centered and X were to take after
playing 23/21 13/7, then XG would report a total equity loss of
2 x 0.283 ~ 0.566 from the combined checker-play error and the
bad take.

XGID=----BBCAAA---Ba-cbbbcA-Bb-:1:1:1:62:0:0:3:0:10

X:Player 1 O:Player 2
Score is X:0 O:0. Unlimited Game, Jacoby Beaver
+13-14-15-16-17-18------19-20-21-22-23-24-+
| X O O O O | | O O X X O |
| X O O O | | O O X O |
| O | | O |
| | | |
| | | |
| |BAR| |
| | | |
| | | |
| | | X | +---+
| | | X X X | | 2 |
| X X X | | X X X | +---+
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 153 O: 97 X-O: 0-0
Cube: 2, X own cube
X to play 62

1. XG Roller++ 21/15 9/7 eq:-0.386
Player: 31.11% (G:3.39% B:0.08%)
Opponent: 68.89% (G:14.80% B:0.45%)

2. XG Roller++ 21/15 13/11 eq:-0.407 (-0.021)
Player: 30.95% (G:3.56% B:0.09%)
Opponent: 69.05% (G:16.59% B:0.72%)

3. XG Roller++ 23/21 13/7 eq:-0.669 (-0.283)
Player: 21.10% (G:2.26% B:0.06%)
Opponent: 78.90% (G:18.81% B:0.14%)

eXtreme Gammon Version: 2.19.207.pre-release

---
Tim Chow

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

eXtreme Gammon Version: 2.19.207.pre-release

My latest trial version says 2.19.211.2671.Pre-release
(with a capital "P").

How many tial/registered versions of XG are out there?

How does who finds what version where?

What are the differences between those versions? Any
change log somewhere?

I think the version I have cheats. :( It must have been
compiled just for me and special delivered... :)

MK

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

On Thursday, May 5, 2022 at 4:01:09 AM UTC+1, Tim Chow wrote:

On 5/4/2022 11:30 AM, [email protected] wrote:

Below, I actually lost 0.537 equity.
All I was trying to do was anchor on the opponent's 4 point for solidity.

You're massively behind in the pip count so you have to hit a shot,
and so you have to stay back for more contact.

I'm reminded of the position below from Mike Corbett's book, "Backgammon Problems." He makes the following rather brutal comment: "If you
advocate making the advanced anchor, then whatever division you're
playing in, demote yourself to the next lower one." He goes on to
explain, "X must capture one of O's checkers to win, and the two point
anchor rates to generate significantly more shots than the four point
with a blot on the two point."

XGID=----BBCAAA---Ba-cbbbcA-Bb-:0:0:1:62:0:0:3:0:10

X:Player 1 O:Player 2
Score is X:0 O:0. Unlimited Game, Jacoby Beaver +13-14-15-16-17-18------19-20-21-22-23-24-+
| X O O O O | | O O X X O |
| X O O O | | O O X O |
| O | | O |
| | | |
| | | |
| |BAR| |
| | | |
| | | |
| | | X |
| | | X X X |
| X X X | | X X X |
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 153 O: 97 X-O: 0-0
Cube: 1
X to play 62

1. XG Roller+ 21/15 9/7 eq:-0.770
Player: 31.85% (G:3.35% B:0.11%)
Opponent: 68.15% (G:15.55% B:0.56%)

2. XG Roller+ 21/15 13/11 eq:-0.785 (-0.015)
Player: 31.61% (G:3.44% B:0.12%)
Opponent: 68.39% (G:16.20% B:0.68%)

3. XG Roller+ 21/13 eq:-0.824 (-0.054)
Player: 29.79% (G:3.14% B:0.11%)
Opponent: 70.21% (G:13.18% B:0.51%)

eXtreme Gammon Version: 2.19.207.pre-release

Thanks for this. I'm surprised, I've never come across this issue before. Positions which look like holding positions except that one side has a 50 point + lead
might not be all that common.

Paul

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

On Wednesday, May 4, 2022 at 4:30:29 PM UTC+1, [email protected] wrote:

Below, I actually lost 0.537 equity.
All I was trying to do was anchor on the opponent's 4 point for solidity.
Why is this a worse idea than putting lumps of chocolate
into a Margherita Pizza?

Thanks for your help.

Paul

XGID=-----BCBC---bB---dcd-A-Bb-:0:0:1:52:5:0:3:0:10
X:Daniel O:eXtremeGammon

Score is X:5 O:0. Unlimited Game, Jacoby Beaver +13-14-15-16-17-18------19-20-21-22-23-24-+
| X O O | | O X X O |
| X O O | | O X O |
| O O | | O |
| O | | O |
| | | |
| |BAR| |
| | | |
| | | |
| X | | X |
| 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: 159 O: 105 X-O: 5-0
Cube: 1
X to play 52

1. XG Roller+ 21/16 6/4 eq:-0.377
Player: 40.22% (G:4.84% B:0.13%)
Opponent: 59.78% (G:11.29% B:0.31%)

2. XG Roller+ 23/21 8/3 eq:-0.913 (-0.537)
Player: 28.58% (G:3.71% B:0.11%)
Opponent: 71.42% (G:16.33% B:0.15%)

3. 4-ply 21/16 8/6 eq:-0.454 (-0.077)
Player: 38.39% (G:4.83% B:0.07%)
Opponent: 61.61% (G:13.16% B:0.34%)

4. 4-ply 8/3 6/4 eq:-0.507 (-0.131)
Player: 38.69% (G:5.56% B:0.11%)
Opponent: 61.31% (G:18.63% B:0.66%)

5. 3-ply 21/14 eq:-0.524 (-0.147)
Player: 36.28% (G:4.17% B:0.12%)
Opponent: 63.72% (G:12.73% B:0.30%)

eXtreme Gammon Version: 2.10

Apart from keeping more contact from the 2 anchor and also stopping opp from dumping behind the 2 anchor, opp may never fill the 3 gaps in front of your anchor before being forced to leave a shot.
--
BD

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