[bluenikki]

DavidKok, on 2025-December-30, 17:22, said:

4=4=0=5', the ugly duckling hand type for this system.

In fact, for some years a guy and I played a Blue Club variant with 4-card majors (but only if < 15 hcp) and 12-14 1NT (but with no major). And we played 6+ 2♣. That threw quite a lot into 1♦ in theory. But if 1♦ was balanced or had a major it had to be 15-17 (15-16 if unbalanced). So 4=4=0=5 with 15-16 had to be 1♦. My partner never quite faced up to that. Of course that hand never came up.

It was fun to play.

[mycroft]

ACBL Alert Procedure, Pre-Alert section said:

Before the auction begins on the first board of a match or round, you must inform the opponents if you have any of these agreements:
1. A 1-level Opening Bid that is not Natural or that is Forcing.

ACBL Convention Charts, Definition of Natural, relevant subsections said:

f. A 1C opening bid showing 3 or more clubs. This opening may also include exactly 4=4=3=2 shape.
g. A 1D opening bid, overcall, or response showing 3 or more diamonds.

and, just to be pedantic:

ACBL Alert Procedure, Definitions said:

All definitions from the ACBL Convention Charts also apply.

I know David doesn't need to care, but [edit: for those of us who do] it's really not that hard to RTFRs. Yes, the ACBL does treat "majors 5, diamonds 4" as a special case, to not (further) intimidate the Life Cs that play this (and will never raise clubs on 5 "you could only have 2 partner", and will always rebid "real" clubs "just to show you it's not 2, partner").(*)

If 1♦ promises 5, the hands with fewer diamonds have to go somewhere. If 1♥ and 1♠ also promise 5 (and who doesn't in these schemes?), then there are the following relevant cases:

• 4=4=3=2
  
• (43)=4=2
  
• 4=4=4=1

that don't have a "place". The rules are quite simple:

• If only 1. is opened 1♣, and 2. and 3. are bid anything else (say "there's always a NT bid for balanced hands" (or "well, 1♦ promises 5 except for ((43)42 and outside NT ranges)") and "we play mini-Roman 2♦", then all the suit openers are Natural and, provided the partnership doesn't play "you can't pass 1♣ because it could be 2", not Forcing either. No Pre-Alert.
  
• If any of 2. or 3. (as well as 1.) are opened 1♣, it's not Natural (it may be Quasi-Natural, provided it is 2 or AKQ and "balanced" if short) and therefore requires a Pre-Alert.

Note that it's not the "odd" 1♦ opener that requires a Pre-Alert (nor is "transfer responses"). But if you're going to Pre-Alert your 1♣ anyway, explaining *why* you've decided to do whatever seems polite. Hence:

akwoo said:

The new-ish ACBL rule is that the 1♦ usually 5+ version requires a pre-alert (as 1♣ is now a quasi-natural rather than natural bid).

and some of his caveats about "it may not be clearly explained, but it usually prompts a question".

1♦ "5 or 4=4=4=1" isn't Pre-Alertable, no - but the 1♣ bid still is (this is the issue I have with the Montréal relay pairs in Calgary) because (43)42 is still opened 1♣, and that makes it not Natural. Again, when you ask, you should find out about the 1♦ bid, because that's *why* the 1♣ is the way it is.

Yes, exactly the issue David brings up about "change the classification in full" is why - if the opponents Pre-Alert their 1♣ opener, you know you're allowed to play your crazy defence against it; if they don't, then you "know" it's Natural (or at least have grounds for a Director Call when they should have), even when they Announce 1♣ as "could be 2".

As to "why" a tiny change on which call to put a single hand is a "change classification in full": it's the same reason why there's a "Bienvenue a Quebec"/"Welcome to Sunny Ontario" sign on the Autoroute 20/Highway 401. You gotta put the border *somewhere*, and things are different on the other side of the border. It could be "2 vs 1", it could be "4 min vs 5" - but in the ACBL it's "majors 4 min, minors 3 min, exception: 4=4=3=2 can go in either minor". On one side is no Pre-Alert, no crazy defences; on the other side is Pre-Alert and crazy defences. They've decided that it's "short" openings that are relevant, not long openings; other RAs can decide differently.

If you choose to play different defences to 5+ suits than 4+ suits (and different defences to 4+ suits than 3+ or 2+ or "4 unless 4333" or whatever), more power to you if they're legal. But because there is no regulatory difference, at least in the ACBL, it's on you to ask/check the card/whatever to see which defence applies to their opening. Enjoy being in the same boat as the Precision pairs (or the "clubs or balanced with transfer responses" pairs, for that matter) who after 1♣-(2♣) have to ask what the overcall means if their defence could differ (as no meaning for that call is Alertable after a Quasi-Natural or Artificial 1♣ opener, despite what the Precision pairs on That Other Site think).

(*) And yes, I know there are better players who play "M5D4" with or without special responses to 1♣ that don't play Life-C and wouldn't be intimidated by the Pre-Alert requirement or Holo-Bolo style defences, but are protected from that anyway. I heard you last time.

[mycroft]

bluenikki, on 2025-December-30, 18:01, said:

In fact, for some years a guy and I played a Blue Club variant with 4-card majors (but only if < 15 hcp) and 12-14 1NT (but with no major). And we played 6+ 2♣. That threw quite a lot into 1♦ in theory. But if 1♦ was balanced or had a major it had to be 15-17 (15-16 if unbalanced). So 4=4=0=5 with 15-16 had to be 1♦. My partner never quite faced up to that. Of course that hand never came up.

It was fun to play.

Arguably the best Precision pair in Canada plays 1♦ "could be zero", because both 2♣ and 2♦ are "11-15, 6+ or *good* 5-card suit +4cM". Looking at their last WBF card, they also include (some) balanced hands with 6 clubs in 1♦. I don't know how they resolve it either, it must be fun. But it's clearly possible.

[DavidKok]

Thank you for the clarification. The ACBL rules for pre-alerting this type of 1♣ opening are better than the Dutch ones. I've never had the fortune of opponents pre-alerting such a system, including on BBO - but likely the games I played were not ACBL-sanctioned, and it was therefore(?) not mandatory.

The current ACBL pre-alert rules do not rest on a single hand type, and they do exactly draw the line at the place I care about most.