Thanks for your help, Ian, and also to Dan Pelton, who e-mailed me. (The online instructions are for the 0.16 build and I confused myself.) I am now able to post a position using Gnu. For the time being, I have given up posting with Snowie (which I would prefer) -- perhaps the instructions don't work quite the same way for the older version (4.1) I have on this machine.
Nack: "Let's compare 65R-21$-53P-21N-21 (Neil's position, first diagram below) to 65R-65R-21 (second diagram below): 1) S slightly improves on D because there is better 64 duplication (triplication)."
Mislav: "...if Black roll 64 he will hit if we played 24/23 13/11. Triplication is illusion IMHO."
Nack: I added "triplication" in parentheses to ensure the reader noticed all three 64 plays. Please focus on "better 64 duplication." In Neil's position, making the 7pt (an option not available in my 65R-65R-21 reference position) is stronger than pointing on the 2pt, and therefore S (24/23 13/11) creates better duplication. The fact that White should hit with 64 does not negate the duplication. In Neil's position, D (13/10) still leaves a great 64 for White (i.e., making the 7pt); conversely, S (24/23 13/11) avoids leaving a constructive alternative for 63 or 54 (in either position).
Nack: "3) S improves on D and $ (as well as U, which is already wrong) because Opp's board with the 5pt is stronger than Neil's with the 3pt."
Ian: "I fail to see how it makes a great deal of difference which point the back man is on, and in general I'd rather stay out of the way on the ace point."
Nack: The taller White's 8pt, the worse it is for Blue to step up. It doesn't become advantageous to step up to the 23pt until White's 8pt is stripped to two or fewer checkers. As it is, Blue, if allowed, would like to play only the deuce (13/11). What's going on is that, due to the extra 3 hitting numbers (additionally supplemented by the duplication of 64 when you stay on the 11pt), which cost extra because Opp owns her 5pt, the 11/10 ace hurts Blue a bit more than the 24/23 ace hurts him.
If Blue could choose on which of four points to place his back checker (with White having three on her 8pt and her 9pt and 10pt vacant as here), I think his preference should be 21pt, 22pt, 24pt, and 23pt in that order. The reason that 21U (Up 24/21) is a bad play here is that the value of unstacking the tall midpoint (and creating a builder) is a much higher priority.
Ian: "... 13/10 provides a builder for the 4 point... this factor drove me to play 13/10 over 24/23 13/11."
Nack: Yes, it's a better builder when it doesn't get hit :)
David Rockwell (referring to 65R-65R-53P-43D-21, the third position below): "Compared to Neil's position, the race is dead even besides the two points you make. So, slotting appears more appealing. However, you would like to run the back checker or develop the mid-point further next turn rather than fighting for the five point. The stripped eight doesn't argue for the slot either. I would develop quietly with D (Down 13-10) and leave myself free to run on sixes."
I'm not sure I follow the part about running with 6s (after D, will you then run with a 6 other than 65?) -- perhaps you're including the concept of hitting with 62 or 63 (which could apply to 53 54 as well) when White leaves one of those blots. That possible nitpick aside, your analysis (and conclusion), which compares D to $, looks on target to me.
The concept I was hinting at in part (when I suggested the third position 65R-65R-53P-43D-21) relates to the comparison of D (13/10) to S (24/23 13/11). White has point-making alternatives with 63 and 54 that she does not have in the other two positions. This elevates the value of D relative to S.
Finally, let's tack a 42 onto the beginning of the sequence, yielding 42P-65R-65R-53P-43D-21, the fourth position below. Now White's 8pt is stripped and her board has the upper hand again. That might swing the pendulum back from D (13/10) to S (24/23 13/11) despite the fact that 63 54 remain duplicated.
Nack
| 161 | |
|---|---|
| |
| 65R-21$-53P-21N-21 | 148 |
Position ID: sHPMATCMZ/ADIA Match ID: cAkFAAAAAAAA | |
| 156 | |
|---|---|
| |
| 65R-65R-21 | 156 |
Position ID: 4HPwAyDgc/ADIA Match ID: cAkFAAAAAAAA | |
| 149 | |
|---|---|
| |
| 65R-65R-53P-43D-21 | 148 |
Position ID: 4HPFAyCMZ/ADIA Match ID: cAkFAAAAAAAA | |
| 143 | |
|---|---|
| |
| 42P-65R-65R-53P-43D-21 | 148 |
Position ID: mGfFAyCMZ/ADIA Match ID: cAkFAAAAAAAA | |
