[barmar]

pilowsky, on 2023-August-16, 20:05, said:

If your partner makes an extraordinary call and you fail to act as you ordinarily would then a new agreement exists.

This is often called the "rule of coincidence". If partner makes a call whose meaning doesn't actually match their hand, and you react in a way that doesn't match what their bid presumably shows, this coincidence would be considered evidence of a concealed partnership understanding.

As I understand it, this rule has never existed officially. It used to be referenced casually, but I think bridge regulators have said that it should not generally be used.

[blackshoe]

While I cannot, off the top of my head, point to any official document that says "don't apply the 'rule of coincidence' to rulings", I agree that we should not.

[mycroft]

Surely, your argument instead is "show me where in the official documentation we mention 'RoC' " :-)?

I do think "why did you" is a good question. I think the answer can be evidence (and it might be exculpatory evidence. More than once I've got something like "I had no idea what was going on so I passed". Yeah, don't do that playing with me(*), but I absolutely know that it happens(*a). I do not think the "catch" should be treated as in itself evidence.

There's also situations where, frankly, it is "baby psych". And yes, everyone has to hear it once; everyone has to get tripped by it once; but in a game where (as an example) the strats are 3000/1750, if the auction went 2♥-p-2♠ (or 1♥-X-1♠) on three hearts and a singleton spade, and the Flight A or B opponents didn't figure it out, I'm not going to state that opener "had more partnership knowledge than the opponents" or "RoC" about that. And in those cases, it shouldn't be really hard to figure it out (especially 2♥-p-2♠-p; 3♠-p-4♥, or 2♥-p-2♠-X; p-p-3♥). At that point "he psyched and he caught it" gets answered "yeah, and so did the kibitzer at the next table. Why didn't you?"(**)

For those pairs around here playing Montréal Relay, if 1♣-p-1♦ fourth hand bids 1M with a short major, and they claim "handled psych" or "how could we know that was psychic?", I will look at them with some suspicion (***). After all, they should have more experience handling "neither of us have shown anything" than the opponents are.

Yes, I know I'm veering very close to the dreaded (and rewritten) "GBK". But the quote (40C1) is "provided that partner has no more reason than the opponents to be aware of the deviation []. Repeated deviations lead to implicit understandings which then form part of the partnership’s methods"(***a). After 30 years and X-thousand masterpoints, if you haven't seen this yet (or "psychic Ogust", provided it is in fact against agreement rather than "we don't mention strength and hope you assume invitational. But when the director is called, we will definitely say that the 'didn't mention' obviously meant 'doesn't say anything about'"), well, go back and read those books in your library. Start with that chapter in Simon.

(*) Meta-agreement 1: "confusing bids are forcing".
(*a) I mean, there's a reason it's an explicit (meta-)agreement :-).
(**) Okay, that's not what I'd say as a director. It is what I would say in the bar after, in a game where I hadn't taken the call.
(***) Frankly, I'm tempted to make it a straight agreement and start Alerting it. "long or short in hearts." Totally legal on the Open Chart (looks like it's not legal Basic+; 1♣ is Quasi-natural, and the "any defence" doesn't apply to Artificial responses. Interesting, wonder if that's an oversight.
(***a) I've done it once with one partner. I've definitely had discussions around "how to defend against opponents who haven't shown suits" with that partner. Partner probably would never find it at the table, and probably wouldn't notice if I did, at least the next time. But...

[mycroft]

Please note, that first comment is not implying that the question is wrong, or shouldn't be asked, or that we shouldn't document "common practise" or "the way we do it" or even "case law" much more than we do. Just that normally blackshoe's objections are in fact the positive, not the "not negative".