[GrahamJson]

The bidding so far doesn’t correspond to any methods that I have come across before, but I’m assuming that somehow spades are agreed. If so I don’t see a problem with making the agreed method bid of 5S. Clearly if you held the two key card option then 5S would be one off in top tricks, in which case partner shouldn’t have gone beyond 4S in the first place. If you really are concerned about being passed out in 5S then there can’t be much wrong with just bidding 7S direct. It’s difficult to picture a hand in which partner is going slamming and seven isn’t a good contract opposite AKQ A A A. What more could you possibly have?

[smerriman]

 PhilG007, on 2018-April-26, 00:38, said:

I also note from the lie of the cards in the diagram that 6♠ and 6NT aredoomed to failure. So N/S are really on a hiding to nothing

 PhilG007, on 2018-April-26, 01:29, said:

From the diagram, I find it hard to see how 7♠ can make Its difficult to see how declarer can avoid at least one loser

6NT shouldn't be too hard to see. Duck a club, then play your club (throwing a spade) and four spades. West has to throw a red card, which gives you your 12th trick.

Having seen that, play 7♠ in exactly the same way, except reverse the first two tricks. Win the club, play a club ("throwing" a spade).

(In fact, you can just ruff two clubs, without even needing the squeeze, hah.)

[msjennifer]

To me it’s unthinkable to find a hand holds no zkey card and not even the Q of trumps will ask a RKC enquiry when it should be the person holding all 5of the keycards.Any how, the 5 H /5S replies show 2/5 keycards without/with the Queen. And this is very logical and simple to understand except the novices and very rarely a few beginners

[nekthen]

 PhilG007, on 2018-April-26, 01:29, said:

From the diagram, I find it hard to see how 7♠ can make Its difficult to see how declarer can avoid at least one loser

Ruff 2♣ A♣ 4♠ 3♦ 3♥ 13

[pescetom]

 Vampyr, on 2018-April-25, 10:35, said:

Well, a fit has been found, so it is very reasonable.

North sees the fit but he has not informed South, and as I said it is not universal to play 4NT as RKCB showing fit in the last suit bid. Some systems play it as plain Blackwood for 4 Aces in absence of a confirmed fit, some play it as RKCB for the first suit bid, some play it as a fit-showing quantitative slam-try. We play it as fit-showing RKCB only under duress from opponents, otherwise the suit must be fixed before either RKCB or control-bids.
But I agree that fit-showing RKCB is common and would be a reasonable guess with a pickup partner.

[GrahamJson]

Looking again at the bidding I think I now understand it. 3C was presumably puppet Stayman, after which 3D showed at least one four card major. North’s 4C bid showed both majors and asked south to bid his major, which he did with his 4S bid. Thus it was established that they have a 4-4 fit in spades, making 4NT unambiguously KKRB (or is it RKKB? I can never remember which.)

Incidentally I disagree with the comment that it should be the hand with most of the controls who should do the asking. In general it is the hand without the controls who has the filler cards and would benefit most by control asking. Taking the current hand as an example, what useful information would South gain by using RKKB? North on the other hand will find out that his two KQs are worth four tricks and should allow him to bid the grand.

[barmar]

 GrahamJson, on 2018-April-26, 08:34, said:

Looking again at the bidding I think I now understand it. 3C was presumably puppet Stayman, after which 3D showed at least one four card major. North’s 4C bid showed both majors and asked south to bid his major, which he did with his 4S bid. Thus it was established that they have a 4-4 fit in spades, making 4NT unambiguously KKRB (or is it RKKB? I can never remember which.)]

It's RKCB: Roman Key Card Blackwood. I'm not sure what your second K is for, Kard?

Quote

Incidentally I disagree with the comment that it should be the hand with most of the controls who should do the asking. In general it is the hand without the controls who has the filler cards and would benefit most by control asking. Taking the current hand as an example, what useful information would South gain by using RKKB? North on the other hand will find out that his two KQs are worth four tricks and should allow him to bid the grand.

But sometimes, as here, the timing of the auction doesn't allow much choice in who does the asking. If you can't establish the trump suit until opener bids 4♠ there's no room for any cue bidding before Blackwood.

[GrahamJson]

RKCB. Of course it is. Goodness knows where I found the extra K.

[aawk]

Assuming 4nt is RKC for ♠ bid 7♠ you got all the key cards and Q of ♠. If that is not enough your partner should not have asked.

[gszes]

 PhilG007, on 2018-April-26, 01:29, said:

From the diagram, I find it hard to see how 7♠ can make Its difficult to see how declarer can avoid at least one loser

look again picturing south ruffing 2 clubs in dummy 6s 1c 3d 3h

[sfi]

 manudude03, on 2018-April-26, 00:49, said:

3C was presumably puppet stayman, so 3D says he does have a 4 card major. Not sure what 4C was meant as, probably asking for preference (though 4D usually asks for that). 7S is an excellent contract and does make on the lie of the cards (so does 6NT, but that's a little tougher to see).

Most likely 4C shows both majors and a slam try. Then 4S cooperates in the slam try and sets the suit.

[miamijd]

 PhilG007, on 2018-April-26, 01:29, said:

From the diagram, I find it hard to see how 7♠ can make Its difficult to see how declarer can avoid at least one loser

Ruff two clubs; draw trump; and claim. WTP?

Cheers,
Mike

[miamijd]

About the only way to reach 7 here is to upgrade opener's hand and start with 2C. I would. How can you get a better 21 point balanced hand than this?

2C 2D(1)
2NT(2) 3C
3S 4NT
5H(3) 7S(4)

(1) waiting
(2) 22-24 ostensibly
(3)All five and the Q
(4) Hmm -- sounds like four spades three hearts three diamonds a club and two club ruffs. If the opponents really have a ten-card club fit, even then partner has a Jack that hasn't been accounted for (22-24), so unless he has AJ tight of clubs, there is trick 13.

If you play some form of Puppet Stayman, the auction is a little different in the middle, but eventually the same.

Cheers,
mike

[fromageGB]

 nekthen, on 2018-April-26, 01:10, said:

A basic tenet of using RKCB is that the response can never be ambiguous. If that is possible, you do not know enough about the hand to be launching a slam investigation

This is rather an implausible statement. Of course the responses are ambiguous. If you are saying this is not a good method to use when the bidding has deprived you of the space to make exploratory discoveries first, then I agree with you, but surely the problem is with your choice of ace asking methods.