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| XGID=-b----E-D---dD--ac-d--a-AA:0:0:1:41:0:0:3:0:10 | |||||
52S-43H-41 | |||||
I would nactate this choice Z rather than D. I realize either is OK. I could visualize Z (Reverse split) more clearly than D if there wasn't a board. Do you have any comments on this?
In Nactation, you can choose to nactate the entire play or just the non-entering portion. (Obviously, David knows this based on his sentence "I realize either is OK," but I'm clarifying for those who might not know.)
For bar/24 13/9, the Nactation for the entire play can be Z (reverse split, smaller number on far side). By the convenience clause (introduced at #6 and defined at #62 in the tutorial), this move can also be nactated S (Split), as there is only one legal way to move a checker on the far side plus bring a checker down to the outer board. [In that sense, bar/24 13/9 resembles what is commonly referred to as opening 41S (24/23 13/9).]
The alternative is to nactate just the non-entering portion (or portions), which in this case is 13/9, or D (Down). Again, the ace cannot legally come down, so there is only one play in the D family.
The choice of nactating (a) the entire play, or (b) the non-entering portion(s), arises frequently (pretty much whenever a non-doublet or sometimes even a doublet is rolled, and a checker from the bar is entering). We just discussed one example. A few other examples are (1) 41 played bar/21 6/5, nactated W or E in entirety, or just $ or I or 5; (2) 64 played bar/21 8/2*, nactated X or C in entirety, or just H or J or 2; (3) 21 entering and covering the 4pt, nactated E in entirety, or just P or I or 4; (4) 55 played bar/20 13/8 8/3(2), nactated M in entirety, or just P or 3.
In some cases, one choice of Nactation seems clearly superior (or at least more easily understood by the most number of people) to me than another. In other cases, I think it's primarily a matter of personal preference.
The first time I can recall that this issue arose was when I nactated bar/24 13/7 as "S," and at least one person thought I meant bar/18, as in "splitting" to the opponent's bar point. Though perhaps less likely, "Z" might have been interpreted the same way (if not with 61 then with 62, somehow reverse-splitting to the bar point with bar/23 24/18. [Veteran nactators have imprinted all such moves as being in the U (Up) family.]
David is experienced with bi-areal nactation, so when he sees "S" (split) or "Z" (reverse split), he reflexively looks for one number to be played on the far side and the other to be played down from the midpoint. [Also, he chooses specifically Z over S for bar/24 13/9 so that he can visually plant the small number immediately on the far side -- there is not even a remote question of whether a 13/12 ace is blocked from coming down (as it always is in the opening).]
On the other hand, a less experienced nactator might see "S" (or its reverse, Z) and his first thought is that S stands for Split -- that the play has something to do with the back checkers, then later (probably a very short time later, but there is still a stutter step) remembers that "S" actually stands for "Split-and-down." [And Z actually stands for reverse-split-and-down.]
Those who are now among the less experienced but who choose to nactate on a regular basis, will in short order have David's reflex, but it's not there yet. I suppose I'm partly responsible for that by using D instead of Z or S for bar/24 13/9 in such situations, but there is a tradeoff and I have a tendency to focus more on immediate mass communication rather than reinforce bi-areal Nactation. Wouldn't it be great, though, if everyone went to "Areal Overview" (less than two pages long) at the end of section 5 of the tutorial and read it right now, once and for all. :)
That said, I don't see it as a hardship either way. Thank you, though, for providing me the opportunity to explain.
Nack