[VixTD]

Club pairs game scored by matchpoints:

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Both pairs are playing Acol with weak NT (EW mini non-vul), 4-card majors and multi-2♦.

West's 3♣ bid was a Bergen-style raise (even over intervention) showing an invitational raise with four spades, but East did not alert it. After he'd passed over 4♥ he realised his error and corrected it, saying he should have alerted 3♣.

Do you think West is OK bidding 4♠ now?

[Vampyr]

Did West definitely think it was a raise, rather than natural and forcing?

[StevenG]

4♠ looks automatic to me - a 6-loser hand with 4-card support. (Assuming no nuances to East's pass)

[campboy]

Seems obvious to bid 4♠ now even taking into account the fact that the player didn't bid 4♠ on the previous round.

Anyway, it's not clear to me that the UI suggests there has been a misunderstanding. If partner passed and then said "sorry, I should have alerted 3♣", that sounds to me as though he knew what it meant all along, but just forgot to alert at the right time.

[ggwhiz]

I don't see pass as a logical alternative for the west hand in the actual auction and a double would fetch a lucky 500.

However, if north had the proper information before they bid 4♥ it could change everything depending on the experience level and tendencies of the north player.

The 4♥ bid is generally thought of as a transfer to 4♠ by them in a lot of circles and on these colours but north is allowed to think they buy the contract or defend 5♣ (which he has defense against) from the MI they had at the time. If I can be convinced that north would bid differently, I can be convinced that e/w would stop in 3♠ some percentage of the time given easts pass of 4♥ in the actual auction.

[helene_t]

Holding an ace, a singleton to lead, and no extra trump length, I think double is an LA. But in that case (and assuming that E decides to pass the double) EW will get 500 instead of 450/480.

I am not sure if pass is an LA although there could certainly be a case that for someone, who fails to set up an FP and holds reasonably defensive assets, pass must be an LA. I think I would double if I were polled but hopefully I am not a peer of someone who plays Bergen over interference (not to mention mini nt with 4-card majors, that strikes me as 100% unplayable).

[Vampyr]

 campboy, on 2016-February-03, 09:40, said:

Seems obvious to bid 4♠ now even taking into account the fact that the player didn't bid 4♠ on the previous round.

Anyway, it's not clear to me that the UI suggests there has been a misunderstanding. If partner passed and then said "sorry, I should have alerted 3♣", that sounds to me as though he knew what it meant all along, but just forgot to alert at the right time.

I think that West is in an odd position. On the one hand partner has passed, but after doing that partner has remembered that 3♣ is a spade raise. So bidding on is totally suggested, but as helene_t asks, is Pass a logical alternative?

Then of course there is the MI. Here it gets complicated. Presumably if North had passed, East would have bid 3♠. Should West now raise, given that he has valued his hand as invitational? I am sure that most people who play Bergen raises have raised to game to show a particular type of hand, but can West do that here?

[barmar]

 campboy, on 2016-February-03, 09:40, said:

Anyway, it's not clear to me that the UI suggests there has been a misunderstanding. If partner passed and then said "sorry, I should have alerted 3♣", that sounds to me as though he knew what it meant all along, but just forgot to alert at the right time.

I think it's far more likely to forget that 3♣ is Bergen in competition than to forget that it's alertable. But West would probably know what kinds of things his partner tends to forget.

[VixTD]

 campboy, on 2016-February-03, 09:40, said:

Seems obvious to bid 4♠ now even taking into account the fact that the player didn't bid 4♠ on the previous round.

Anyway, it's not clear to me that the UI suggests there has been a misunderstanding. If partner passed and then said "sorry, I should have alerted 3♣", that sounds to me as though he knew what it meant all along, but just forgot to alert at the right time.

It was clear to everyone that East had forgotten that 3♣ was conventional, rather than knew it was conventional and forgot to alert.

I was North, and wouldn't have acted differently with a timely alert. I didn't say anything at the time, as I doubted that pass was a logical alternative for West, but then it did seem that bidding 4♠ to introduce the suit you have already shown after limiting your hand is demonstrably suggested, and it doesn't take many passing peers (one in ten, or so) to make this work.

[RMB1]

There should be no MI issue. North should have been offered the option of changing his call (if his choice had been affected by the misinformation), because the misinformation had been corrected before South's call. No doubt North silently offered himself this option and decided not to change and the auction continued.

[barmar]

 RMB1, on 2016-February-03, 12:50, said:

There should be no MI issue. North should have been offered the option of changing his call (if his choice had been affected by the misinformation), because the misinformation had been corrected before South's call. No doubt North silently offered himself this option and decided not to change and the auction continued.

No doubt, since VixTD just wrote "I was North, and wouldn't have acted any differently with a timely alert".