XGID=-b----E-CA--dD---c-ccA--A-:0:0:1:31:0:0:0:0:10

Score is X:0 O:0. Unlimited Game
+13-14-15-16-17-18------19-20-21-22-23-24-+
| X O | | O O X X |
| X O | | O O |
| X O | | O O |
| X | | |
| | | |
| |BAR| |
| | | X |
| O | | X |
| O X | | X |
| O 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: 157 X-O: 0-0
Cube: 1
X to play 31

---
Tim Chow

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

On 6/8/2023 9:15 AM, Timothy Chow wrote:

XGID=-b----E-CA--dD---c-ccA--A-:0:0:1:31:0:0:0:0:10

Score is X:0 O:0. Unlimited Game  +13-14-15-16-17-18------19-20-21-22-23-24-+
 | X           O    |   | O  O  X        X |
 | X           O    |   | O  O             |
 | X           O    |   | O  O             |
 | X                |   |                  |
 |                  |   |                  |
 |                  |BAR|                  |
 |                  |   | X                |
 | O                |   | X                |  | O           X    |   | X                |  | O           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: 157 X-O: 0-0
Cube: 1
X to play 31

I don't see that anchoring is clearly superior to making the five point.
Maybe if there were more than nine in the zone...

And since I'm not sure anchoring is better, I'll make the five point.

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

XGID=-b----E-CA--dD---c-ccA--A-:0:0:1:31:0:0:0:0:10

Score is X:0 O:0. Unlimited Game
+13-14-15-16-17-18------19-20-21-22-23-24-+
| X O | | O O X X |
| X O | | O O |
| X O | | O O |
| X | | |
| | | |
| |BAR| |
| | | X |
| O | | X |
| O X | | X |
| O 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: 157 X-O: 0-0
Cube: 1
X to play 31

There's an early-game heuristic that I learned from Nack Ballard:
either 5pt beats either 4pt. (You may find Stick's version more
memorable: either the 5pt or the 20pt beats either the 4pt or the
21pt.) Here, that would suggest making the 5pt rather than anchoring
on the 4pt. However, XG says that this position is an exception.
O's offensive position has developed enough that defending against
her threat to make her 4pt has increased significantly in value.
One way to think about it is that if X plays 8/5 6/5 and then O
points on X's head and X dances, then O will probably double. That's
quite a few bad sequences for X, whereas after 24/21 9/8, I'm having
a hard time seeing any sequences after which O would double.

In the variant, there are fewer ways for O to make her 4pt, and XG
thinks the decision is closer, but still wants to anchor.

1. Rollout¹ 24/21 9/8 eq:-0.107
Player: 46.98% (G:10.18% B:0.31%)
Opponent: 53.02% (G:10.08% B:0.38%)
Confidence: ±0.013 (-0.120..-0.094) - [100.0%]

2. Rollout¹ 8/5 6/5 eq:-0.189 (-0.082)
Player: 46.03% (G:13.63% B:0.80%)
Opponent: 53.97% (G:19.06% B:0.93%)
Confidence: ±0.017 (-0.205..-0.172) - [0.0%]

3. Rollout¹ 24/21 6/5 eq:-0.211 (-0.105)
Player: 44.87% (G:10.46% B:0.33%)
Opponent: 55.13% (G:13.26% B:0.49%)
Confidence: ±0.015 (-0.226..-0.196) - [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=-b----E-CA--dD---c-dbA--A-:0:0:1:31:0:0:0:0:10

Score is X:0 O:0. Unlimited Game
+13-14-15-16-17-18------19-20-21-22-23-24-+
| X O | | O O X X |
| X O | | O O |
| X O | | O |
| X | | O |
| | | |
| |BAR| |
| | | X |
| O | | X |
| O X | | X |
| O 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: 158 X-O: 0-0
Cube: 1
X to play 31

1. Rollout¹ 24/21 9/8 eq:-0.083
Player: 47.25% (G:10.17% B:0.29%)
Opponent: 52.75% (G:9.74% B:0.39%)
Confidence: ±0.006 (-0.090..-0.077) - [100.0%]

2. Rollout¹ 8/5 6/5 eq:-0.113 (-0.029)
Player: 47.72% (G:14.39% B:0.76%)
Opponent: 52.28% (G:17.40% B:0.89%)
Confidence: ±0.008 (-0.121..-0.104) - [0.0%]

¹ 5184 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 6/10/2023 8:16 AM, Bradley K. Sherman wrote:

Timothy Chow <tchow12000@yahoo.com> wrote:

...
There's an early-game heuristic that I learned from Nack Ballard:
either 5pt beats either 4pt.
...

That makes sense. Any heuristics for 4pt vs. 7pt?

I don't know of any succinct ones. I think that the 4pt/7pt question
was going to be addressed by Paul Magriel in an upcoming book in the Ballard/Weaver series of books on backgammon openings, but I fear that
the book will never see the light of day.

---
Tim Chow

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

Timothy Chow <tchow12000@yahoo.com> wrote:

...
There's an early-game heuristic that I learned from Nack Ballard:
either 5pt beats either 4pt.
...

That makes sense. Any heuristics for 4pt vs. 7pt?

--bks

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

On 6/10/2023 8:41 AM, Timothy Chow wrote:

On 6/10/2023 8:16 AM, Bradley K. Sherman wrote:

Timothy Chow  <tchow12000@yahoo.com> wrote:

...
There's an early-game heuristic that I learned from Nack Ballard:
either 5pt beats either 4pt.
...

That makes sense.  Any heuristics for 4pt vs. 7pt?

I don't know of any succinct ones.  I think that the 4pt/7pt question
was going to be addressed by Paul Magriel in an upcoming book in the Ballard/Weaver series of books on backgammon openings, but I fear that
the book will never see the light of day.

My hurestic is:


Make offensive or defensive 5 point before offensive or defensive 4 or
bar point.


Don't remember where I got it from, but it seems to work. Most of the
time anyway.

As for 4 vs bar point, the four point is more valuable than the bar
point once your opponent is off the ace point. Once they are, the bar
point doesn't block sixes and it's probably better to have another
homeboard point.

--
Ah....Clem
The future is fun, the future is fair.

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

XGID=-a--a-ECC---cB---bbdb-A-A-:0:0:1:31:0:0:0:0:10

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 X |
| X O O | | O O |
| | | O |
| | | O |
| | | |
| |BAR| |
| | | X |
| | | X |
| O X X | | X |
| O X X | | X |
| O X X | | X O O |
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 147 O: 148 X-O: 0-0
Cube: 1
X to play 31

---
Tim Chow

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

XGID=-a--a-ECC---cB---bbdb-A-A-:0:0:1:31:0:0:0:0:10

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 X |
| X O O | | O O |
| | | O |
| | | O |
| | | |
| |BAR| |
| | | X |
| | | X |
| O X X | | X |
| O X X | | X |
| O X X | | X O O |
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 147 O: 148 X-O: 0-0
Cube: 1
X to play 31

Nack Ballard has an early-game rule of thumb, "Either 5pt beats
either 4pt." But this position is an exception because X urgently
needs to marshall a defense against O's strong offensive position.
She has a very good prime developing as well as some attacking
chances.

1. Rollout¹ 24/21 22/21 eq:-0.059
Player: 47.80% (G:8.84% B:0.24%)
Opponent: 52.20% (G:7.51% B:0.29%)
Confidence: ±0.012 (-0.071..-0.047) - [100.0%]

2. Rollout¹ 8/5 6/5 eq:-0.207 (-0.148)
Player: 45.09% (G:12.99% B:0.56%)
Opponent: 54.91% (G:16.80% B:0.70%)
Confidence: ±0.013 (-0.220..-0.194) - [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 Monday, November 27, 2023 at 9:30:32 AM UTC-5, Timothy Chow wrote:

XGID=-a--a-ECC---cB---bbdb-A-A-:0:0:1:31:0:0:0:0:10

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 X |
| X O O | | O O |
| | | O |
| | | O |
| | | |
| |BAR| |
| | | X |
| | | X |
| O X X | | X |
| O X X | | X |
| O X X | | X O O |
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 147 O: 148 X-O: 0-0
Cube: 1
X to play 31
Nack Ballard has an early-game rule of thumb, "Either 5pt beats
either 4pt." But this position is an exception because X urgently
needs to marshall a defense against O's strong offensive position.
She has a very good prime developing as well as some attacking
chances.

1. Rollout¹ 24/21 22/21 eq:-0.059
Player: 47.80% (G:8.84% B:0.24%)
Opponent: 52.20% (G:7.51% B:0.29%)
Confidence: ±0.012 (-0.071..-0.047) - [100.0%]

2. Rollout¹ 8/5 6/5 eq:-0.207 (-0.148)
Player: 45.09% (G:12.99% B:0.56%)
Opponent: 54.91% (G:16.80% B:0.70%)
Confidence: ±0.013 (-0.220..-0.194) - [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

The explanation isn't really on point. The main reason we need to make the anchor here instead of making our own five point is that it is much harder to make _that_ anchor. It may take a couple/few turns if we pass up making the 5pt now but we'll more
than likely make it in the future. If we don't make the 21pt anchor we may never make it because it's so hard to make. (Not even that we get attacked, it's just hard to make) Even if we take BOTH checkers from the opp's 6pt and toss them back on his
midpoint completely stripping any real chance of attacking us or priming us any time in the near future it's still clearly correct to make the advanced anchor.

Stick

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