c_corgi

I like this better. The alternative of playing LHO to have led a singleton ♦ against slam holding a side ace and a singleton trump seems strange. However, it may be that the auction suggested we didn't care about the ♣A and might also be missing a different ace. This is another reason to want to know what the auction was.

If 4S was bid as a place to play with a 4 card suit, I would expect him to have lots of values in spades and diamonds and nothing much in the rounded suits. Otherwise, why is he avoiding 3NT and not making a slam try? If he has a club control it is likely a singleton, in which case the A♣ doesn't cost given your confidence that East has no club control. I am not even convinced there was any MI - the fact that East's explanation is plausible, whereas West's is not seems like strong evidence of misbid rather than misexplanation.

a) A♣ b) A♣. This sounds like another way of announcing it as a spade control. c) Q♥. The explanation sounds sufficiently odd that they are probably having a misunderstanding. A bit guessy, but I try passive.

Indeed, especially as OP makes no mention of it being alerted as such. It is also not clear whether N/S both knew that they were playing in hearts. If so then I agree with OP that 6H was wild or gambling. If not, and the lack of alerts contributed to this confusion, then I have more sympathy with the 6♥ bid.

South's hand looks like more than zero defensive tricks to me. That is because I expect to be facing something like 2-1 or 2-2 in the majors. It seems unreasonable to expect South to realise that North has 4 spades before evaluating his defence.

So the SEWoG is catering for a 5-0 diamond break in a seriously erroneous fashion. It is therefore not related to the infraction, which merely induced declarer to play for a 5-0 diamond break and a split score is therefore permitted. "Usually denies a 4 card major" sounds like "a 4 card major may be suppressed if the suit quality is poor" rather than "this initiates a scramble sequence", so ruling it was MI seems very reasonable. It sounds like the AC got this one right and both sides should receive the adverse result.

If West has 3♦ and 4♣, then I think he is more likely to lead a diamond, trying to hit partner if he has the Q; more likely to lead a club, trying to set up his own suit if he has the ♦A as an entry. I wonder what the tipping point would be in terms of quality of West's club suit.

I hope that L70A would be interpreted so as to protect the claimer against such shenanigans. That South would - in real life - cash the spade is not a doubtful point, since declarer would otherwise be likely to make the rest of the tricks (in the actual position) and could have ♦QJ (in which case he would be guaranteed to do so).

Declarer has no more stated an intention to take two tricks (his queens) than he has stated an intention to contribute the ♦10 to the next trick. He has simply accepted the inevitable cashing of the 13th spade, a consequence of which is that he will make the last two tricks. I agree with chrism: it makes no sense to interpret declarers statement in the light of the 13th spade not being cashed. It feels like lamford is right and the finesse is now obligatory, although as is often the case when lamford is right, it is not what I would intuitively consider fair! The missing spade is interesting. Is declarer obliged to assume that the missing spade is with North if doing so would cause him to go wrong? After all, he doesn't believe it has been played and it would not be irrational to assume that South would have cashed it if he had it - although it would mean something strange had happened in the auction.

I think that is the crux of it. What if South had called the director after West's pass but before North reached towards 5C? Would that be: 1) an antic to get N/S out of a hole; or 2) a legitimate - or even obligatory - action to prevent an irregularity? If it would be (2), I would be more inclined to suggest to South this is what should have been done rather than invoke L23.

I assume that a player who thought 3H was a sensible rebid also thought that 3H was NF and was content not to describe the hand any further. That means that pass is an L/A. South should be given the opportunity to explain why the assumption is not valid in this case (e.g. 3H was F, must protect expected +140 etc), but I doubt that any such explanation would sway my judgement.

3♠. Partner can then choose the strain. If I choose the strain now I am guessing.

Is there really MI here? It seems to me that "no agreement" differs little from "natural and forcing". If I were to sit opposite any of you with no agreement and I bid 3D to play, wouldn't you think I was mad? Unless East might know of a tendency for West to make surprising interpretations of undiscussed sequences it looks like a clear misbid rather than MI. If there is damage, South would have bid differently over "no agreement" than over "natural and forcing". If that is the case, to explain "no agreement" rather than "natural and forcing" would be exploiting this uncertainty. Surely a clear explanation of an implied understanding is better than a confusing and vague cop-out. I think West should have corrected the explanation as a matter of good form, but I am not sure that he is legally obliged to do so unless he still thought it might be wrong.

In that case, 5D should mean "Partner, please guess the final contract; if you guess wrong, I hope we get lucky."

Over 4D you have owned up to a heart control (assuming not playing last train). You haven't really made a value judgement yet. From partner's POV you could have ♠KJTxxx ♥Q ♦Jxx ♣Jxx. This hand might make a cooperative cue and respect a signoff and partner must allow for it. Phil's example hand is obviously much better and you need to let partner know if that is what you hold. Partner's splinter followed by a signoff doesn't mean "I have a slam drive, but no control in the unbid suit", it means "We have slam values if you have a suitable hand, but I am not worth the 5 level myself. If you have a suitable hand bid on, then we can check for controls/KC etc. as appropriate."