[shevek]

With West dealer, auction goes

1♠ - (2♣) - 3♠ - (5♣)
4NT

North doesn't accept.
Away from the table, West admits she didn't see 5♣.
Pushing my luck, I ask her what 5NT by her would mean over 5♣.
"Dunno, maybe RKC"

What should happen now?

[jillybean]

Good problem.

[barmar]

Can we ask East what 5NT would mean to him? Or is his answer too likely to be influenced by having seen the insufficient 4NT bid?

[pran]

To me this is no problem at all: I would simply inform West that she must replace her insufficient bid (not accepted by North) with any legal call except double, and that East is required to pass for the remainder of the auction on this board.

East's statement ("Dunno, maybe RKC") simply confirms that they have no kind of agreement for any call to "take over" as Blackwood if 4NT is blocked by interference. (If they could show reliable evidence of such agreement I would allow the insufficient 4NT to be replaced by such call under Law 27B1{b}.)

[gordontd]

pran, on 2012-May-20, 23:33, said:

To me this is no problem at all: I would simply inform West that she must replace her insufficient bid (not accepted by North) with any legal call except double, and that East is required to pass for the remainder of the auction on this board.

East's statement ("Dunno, maybe RKC") simply confirms that they have no kind of agreement for any call to "take over" as Blackwood if 4NT is blocked by interference. (If they could show reliable evidence of such agreement I would allow the insufficient 4NT to be replaced by such call under Law 27B1{b}.)

I agree.

[iviehoff]

shevek, on 2012-May-20, 21:16, said:

Pushing my luck, I ask her what 5NT by her would mean over 5♣.

You were pushing your luck, because you mustn't do that. You should of course inform her that if she has a call of same or narrower meaning than 4N available, she can make it without penalty. But then it is for her to persuade you she has such a call available, not for you to look for it.

[barmar]

iviehoff, on 2012-May-21, 03:22, said:

You were pushing your luck, because you mustn't do that. You should of course inform her that if she has a call of same or narrower meaning than 4N available, she can make it without penalty. But then it is for her to persuade you she has such a call available, not for you to look for it.

Right. There's no reason to ask about 5N specifically, because the law regarding replacing a bid with a sufficient version of the same denomination only applies to natural calls. So if they have a way to do RKC in this situation, it doesn't matter whether it's 5N or something else.

[TimG]

deleted -- off topic...

[pran]

barmar, on 2012-May-21, 07:58, said:

Right. There's no reason to ask about 5N specifically, because the law regarding replacing a bid with a sufficient version of the same denomination only applies to natural calls. So if they have a way to do RKC in this situation, it doesn't matter whether it's 5N or something else.

We use the 2007 laws now:

Law 27B1{b} said:

if, except as in (a), the insufficient bid is corrected with a legal call that in the Director’s opinion has the same meaning* as, or a more precise meaning* than, the insufficient bid (such meaning being fully contained within the possible meanings of the insufficient bid) the auction proceeds without further rectification, but see D following.

This law applies to conventional calls as well as natural calls, and there is no requirement that the replacement call must nominate the same denomination as the insufficient bid.

[barmar]

pran, on 2012-May-21, 15:21, said:

This law applies to conventional calls as well as natural calls, and there is no requirement that the replacement call must nominate the same denomination as the insufficient bid.

That was my point. The TD, in asking what 5N would have meant, was apparently thinking about L27B1a, which applies when the insufficient bid is replaced with the lowest sufficient bid in the same denomination. But it only applies when they're both not artificial. Since 4N was RKC, this law is irrelevant, so there's no reason for him to bring up 5N.

[pran]

barmar, on 2012-May-21, 18:57, said:

That was my point. The TD, in asking what 5N would have meant, was apparently thinking about L27B1a, which applies when the insufficient bid is replaced with the lowest sufficient bid in the same denomination. But it only applies when they're both not artificial. Since 4N was RKC, this law is irrelevant, so there's no reason for him to bring up 5N.

OK,
a slight misunderstanding by me about your comment, sorry.