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31P Nactation

Posted By: Nack Ballard
Date: Thursday, 12 June 2014, at 4:05 a.m.

In Response To: 31P Nactation (Art Grater)

Why doesn't Nactation use defaults when obvious? For example, if you open with a 31 and make your 5 point, then 31 should work as well as 31P.

It's a fair question. As a minimalist, I'm always looking for ways to save a character, if there is no significant drawback(s) in doing so.

If "31" is used to represent 31P on an opening play, where does one draw the line? Is 65R-31-xxx (meaning 65R-31P-xxx) still okay? 32S-31-xxx? 43U-31-xxx? 62S-31-xxx? 64S-31-xxx? 63R-31-xxx? I can hear your answer: "Use your judgement and only omit the third character when the best play is truly obvious." Okay, I get it, but read on.

I'm hoping that before long, someone will take up the project of programming Nactation. (I am not a programmer.) Its rules are completely unambiguous, stable and relatively simple to apply to areal characters (BEACON, RDJI, UV, FGMY and doublet SZQ), and a complete system can be based on those alone. Numerals will soon be stable and would be the next to add, though again, they're not necessary. Style characters (HKLPTWX and symbols) can be added later.

I feel confident that a Nactation program will exist sooner or later, and with that eventuality in mind, I've had to contemplate carefully how to treat "assumption." To that end, sections 8 and 9 of the new tutorial are already partially outdated. A human will probably understand that if, for 41\$-44, the nactator writes "D" s/he means 24/20*/16* 13/9(2), but a program will interpret it as the (properly used) sole member of the D family, which is the uber-whopper 13/9(4)! For this reason, and also because assumption is a slippery slope in general (there can be closer and closer shades of obviousness, and what is obvious to one person isn't always obvious to another), I announced here (under the "Assumption" subheader) that from now on, a dot (or period) should be added underneath or after assumption characters.

It occurs to me that a dot could be added by itself to a roll. To a human, it would simply mean "make the obvious play," and to a sufficiently smart program it would mean "make the best play according to XGR++ evaluation." However, until a Nactation program is interfaced in such a way to a bot, it will have no way of interpreting the intended play for either opening "31" (the roll by itself) or "31." (with the dot added). Therefore, until that time arrives, the assumption dot must be confined to communication between humans.

Writing a roll by itself without a dot, as you suggest, is possible. Indeed, once upon a time I did it myself for obvious early game moves. If you write just "31" the absence of a character itself is an implied assumption that tells the interpreter he must fill in the obvious play himself.

You should be aware of a couple of other ways that roll-only manifests: (1) Forced moves, such as entering two checkers from the bar, and (2) The maximum number of checkers possible with the roll are borne off.

The first situation cannot conflict (because it is forced), but the second situation can. If roll-only assumption is allowed, you could (for example) be bearing off with a tall 6pt, a checker on the 4pt and your other points vacant, where "31" would mean the obviously best 6/5 6/3 (by assumption), yet it would also mean 4/off (by the max-off convention). Another rule would have to be added; for example to determine which of assumption or max-off trumps the other, or perhaps instead to disallow roll-only assumption in the bearoff and for any other situation for which roll-only might later be discovered to be a natural fit.

There is another concern governing roll-only, which will be clear if you examine the following examples. (a) Does "63S-31" mean that the assumed 31P has already been played, or does it mean (as it so often does), "How do you play 63S-31?" (b) If I write 21\$-64K-31, have the two checkers already entered or not? (c) If I end my sequence with 31 in the bearoff situation described in the previous paragraph, has 6/5 6/3 already been played or not?

The easiest solution (apart from disallowing roll-only altogether) is to disallow roll-only when it is the final move of a sequence, unless there is some clue in context that clearly indicates otherwise. [An example of this "unless" would be in a match nacscription, where roll-only at the end of a game can mean gin or fair resignation, and it is the change in score, and/or the fact that a new game subsequently begins that makes it clear what happened and that it is certainly not a what-do-you-play-with this-roll problem.]

If one factors in the limitations explained above, there would seem to be no obstacle to using roll-only assumption for super-obvious opening moves. That is, except for uniformity! File names and subject headers with 31P and 65R (etc.) have been bandied about for several years. To find short early game sequences with "31" or "65" (etc.) would require a second search, and if no-roll assumption is used for second-roll moves, searching could take four times as long, etc. By the same token, positions would no doubt be rolled out twice or multiple times as much as needed when rollateers do not check for all possible doppelgangers.

By design, there are often several ways to nactate the same move. Generally, though, there are consensus Nactations for the first roll, and usually for the second and third rolls of the game. I doubt anyone will mind terribly if you post a rollout for 42P-43 and label the file and the subject header "42-43," but if I notice it and think it's a rollout or post worth finding later, I will rename any copy I might get of the said file and add a subject header entitled "42P-43."

So, that is one more caveat to consider! If you still like the idea of no-roll assumptions, my advice is to wait until you are a few to several rolls into the game; however, I won't get bent out of shape if you start marching to your own beat by dropping the P from opening "31P," etc. :)

Nack

• 31P Nactation
Art Grater -- Wednesday, 11 June 2014, at 9:51 a.m.
• 31P Nactation
Jason Lee -- Wednesday, 11 June 2014, at 12:17 p.m.
• 31P Nactation
Nack Ballard -- Thursday, 12 June 2014, at 4:05 a.m.
• 31P Nactation
Taper_Mike -- Thursday, 12 June 2014, at 5:47 a.m.

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