GNU Backgammon Position ID: aLeDAxDYTvATAA
Match ID : cIkuAAAAAAAE
+24-23-22-21-20-19------18-17-16-15-14-13-+ O: gnubg
| O O O | | O O X X | 0 points
| O O | | O O X |
| O | | O X |
| | | X |
| | | 6 |
| |BAR| |v 1 point match
| | | |
| | | |
| X | | O |
| X X X | | O | Rolled 53
| O X X X | | X O | 0 points
+-1--2--3--4--5--6-------7--8--9-10-11-12-+ X: axel
Pip counts: O 132, X 137

Can also be rephrased as "How many blots and where?"

Best regards

Axel

On 12/23/2022 1:39 PM, Axel Reichert wrote:
> GNU Backgammon Position ID: aLeDAxDYTvATAA
> Match ID : cIkuAAAAAAAE
> +24-23-22-21-20-19------18-17-16-15-14-13-+ O: gnubg
> | O O O | | O O X X | 0 points
> | O O | | O O X |
> | O | | O X |
> | | | X |
> | | | 6 |
> | |BAR| |v 1 point match
> | | | |
> | | | |
> | X | | O |
> | X X X | | O | Rolled 53
> | O X X X | | X O | 0 points
> +-1--2--3--4--5--6-------7--8--9-10-11-12-+ X: axel
> Pip counts: O 132, X 137
>
> Can also be rephrased as "How many blots and where?"

X is slightly behind in the race. If he were well ahead in the
race, then I would play safe with 15/10 8/5. If he were well
behind in the race then I think I would risk a direct shot for
the sake of better containment; 13/8 13/10 looks better to me
than 8/3 6/3, because it blocks sixes and also makes it easier
for X to extend his prime.

Given that X is slightly behind in the race, I'm not sure which
of these two strategies is better. The "safe" play still gives
O four hitting rolls. Still, I think I would play safe, since
getting hit is pretty bad.

---
Tim Chow

On 12/23/2022 1:39 PM, Axel Reichert wrote:
> GNU Backgammon Position ID: aLeDAxDYTvATAA
> Match ID : cIkuAAAAAAAE
> +24-23-22-21-20-19------18-17-16-15-14-13-+ O: gnubg
> | O O O | | O O X X | 0 points
> | O O | | O O X |
> | O | | O X |
> | | | X |
> | | | 6 |
> | |BAR| |v 1 point match
> | | | |
> | | | |
> | X | | O |
> | X X X | | O | Rolled 53
> | O X X X | | X O | 0 points
> +-1--2--3--4--5--6-------7--8--9-10-11-12-+ X: axel
> Pip counts: O 132, X 137
>
> Can also be rephrased as "How many blots and where?"

Race is about even and O has a strong board so 15/10 8/5 for me. We can
make more points later and O still has work to do to get her straggler home.

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

Axel Reichert <mail@axel-reichert.de> writes:

> GNU Backgammon Position ID: aLeDAxDYTvATAA
> Match ID : cIkuAAAAAAAE
> +24-23-22-21-20-19------18-17-16-15-14-13-+ O: gnubg
> | O O O | | O O X X | 0 points
> | O O | | O O X |
> | O | | O X |
> | | | X |
> | | | 6 |
> | |BAR| |v 1 point match
> | | | |
> | | | |
> | X | | O |
> | X X X | | O | Rolled 53
> | O X X X | | X O | 0 points
> +-1--2--3--4--5--6-------7--8--9-10-11-12-+ X: axel
> Pip counts: O 132, X 137
>
> Can also be rephrased as "How many blots and where?"

No one mentioned 15/10 13/10. Over the board I played the safe 15/10
8/5. This loses the fewest gammons, which is irrelevant in a
1-pointer. From the candidates volunteering a direct shot the one
blocking the opponent's 6s is best. The 10-point is not that valuable,
but I was surprised how bad making the 3-point is. Maybe there is
too little ammunition in the zone for a serious blitzing threat and
giving up the slotted 8-point may prove a liability.

Best regards

Axel

Rolled 53:
1. Rollout 13/10 13/8 Eq.: +0.127
0.564 0.134 0.011 - 0.436 0.120 0.010 CL +0.127 CF +0.127
[0.002 0.006 0.002 - 0.002 0.006 0.004 CL 0.005 CF 0.005]
Full cubeful rollout with variance reduction
718 games, Mersenne Twister dice gen. with seed 445048384 and quasi-random dice
Stop when std.errs. are small enough: limit 0.0050 (min. 36 games)
Play: 0-ply cubeful [expert]
Cube: 2-ply cubeful prune [world class]
2. Rollout 15/10 8/5 Eq.: +0.079 (-0.049)
0.539 0.080 0.006 - 0.461 0.066 0.003 CL +0.079 CF +0.079
[0.002 0.006 0.002 - 0.002 0.005 0.001 CL 0.005 CF 0.005]
Full cubeful rollout with variance reduction
516 games, Mersenne Twister dice gen. with seed 445048384 and quasi-random dice
Stop when std.errs. are small enough: limit 0.0050 (min. 36 games)
Play: 0-ply cubeful [expert]
Cube: 2-ply cubeful prune [world class]
3. Rollout 15/10 13/10 Eq.: +0.050 (-0.077)
0.525 0.102 0.004 - 0.475 0.089 0.005 CL +0.050 CF +0.050
[0.002 0.006 0.002 - 0.002 0.005 0.001 CL 0.005 CF 0.005]
Full cubeful rollout with variance reduction
490 games, Mersenne Twister dice gen. with seed 445048384 and quasi-random dice
Stop when std.errs. are small enough: limit 0.0050 (min. 36 games)
Play: 0-ply cubeful [expert]
Cube: 2-ply cubeful prune [world class]
4. Rollout 8/3 6/3 Eq.: -0.034 (-0.161)
0.483 0.109 0.011 - 0.517 0.118 0.005 CL -0.034 CF -0.034
[0.002 0.006 0.004 - 0.002 0.005 0.001 CL 0.005 CF 0.005]
Full cubeful rollout with variance reduction
712 games, Mersenne Twister dice gen. with seed 445048384 and quasi-random dice
Stop when std.errs. are small enough: limit 0.0050 (min. 36 games)
Play: 0-ply cubeful [expert]
Cube: 2-ply cubeful prune [world class]

On 12/26/2022 3:32 AM, Axel Reichert wrote:
> No one mentioned 15/10 13/10.

I considered it briefly but didn't think it could possibly be better
than 13/10 13/8.

> but I was surprised how bad making the 3-point is. Maybe there is
> too little ammunition in the zone for a serious blitzing threat and
> giving up the slotted 8-point may prove a liability.
It's not so much the ammunition in the zone, as the fact that you're
not going to be going all-out for a blitz when you've escaped your
back checkers (plus gammons don't matter). The fourth point in your
board will be helpful if O runs into the outfield and you hit her,
but the priority is to try to prevent her from running into the
outfield in the first place, and to make sure you have enough outfield
coverage to hit her if she does run out.

---
Tim Chow