Posted 2016-January-13, 12:19
You can play Blue Club (at least I know a pair that claims to). 1NT is 13-15, with certain 11s and 12s added. 5-point range, no problem.
Woodson Two-Way NT was a big one: 10-12 or 16-18. I haven't seen it much in the last 20 years for some reason.</sarcasm>
50 years ago there was a hate on for 10-12 NTs (especially ones that are aggressively shaded), so they put a floor down. I would like to see that floor revisited, now that the floor for "normal" openings includes a majority of 10-12 NT hands - the reason to play this is becoming irrelevant (you're preempting the entire 1 level on hands that are passed by "standard" systems; now more than half of them are trivally opened, usually with a more constructive call). But that'll never happen, because the reason it was hated in the first place is it's raison d'etre, so they won't liberalize to give that option back. Having said that, the reason the upgrade policy is so draconian is that people were abusing it "we can't *play* 9-12, so we'll agree to play "10-12 with liberal upgrades", and liberal == "all 9s that aren't 8s".
I assume most here remember "the Bergen Rule" and why DISALLOWED, 7, includes "weak 2s with a range wider than 7 HCP or could by agreement be shorter than 5 cards". Again, as far as I know, it wasn't "unplayable absent a wire", it was "too many people complained about playing against it, whether they got good or bad results from it."
I know that the 5 range makes it convention-denied to play by agreement the "Prof. Silver NT": "12-14, or 15-17 if partner forgot again"; which is convenient.
I have played, in the ACBL, an "8-'we don't have game'" (15 or so) NT, third seat playing EHAA. It never came up. It was in fact playable, but only because of the high information content of the initial pass.
So, it's a combination of "we don't think you can play it without 'assistance'" (or, as is the rule for odd-even *carding*, "we don't think you can play it without *giving* 'assistance'") and "we don't think the rank-and-file want to deal with this." Add in a sprinkling of "we're not banning this convention" and "we can't afford to annoy this well-known player" (mostly from when we converted from "regulating conventions by name", but not always), and you pretty much have the entire GCC.
re: two-suited O/C of NT: it's not just the S-word. When it was GCC legal, I used to play CRaSh/NT. Whether I'd go back were it legal/I was in SoCal now that I'm not a Junior, I don't know :-)
Note: there's an awful lot of personal opinion here. While I may occasionally work for the ACBL, I *never* speak online for them.
When I go to sea, don't fear for me, Fear For The Storm -- Birdie and the Swansong (tSCoSI)