Thank you for the discussion. This is an interesting deal, and there are multiple good opportunities to compare and learn from other styles.
In general I am distrustful of auctions now that both hands are known. I think many people would struggle to get to a slam (yes really), let alone the grand, let alone the best grand. Which obviously is, uh, wait. Which one was it again? 7
♦, 7
♥ or 7NT?
I'll try to be objective, even having seen both hands. With a shape first approach to 2/1 GF, my auction would be:
1
♥-2
♣; (1
♥ natural, 2
♣ 0+ as explained upthread)
2
♦-2
♥; (2
♦ natural, 2
♥ showing the SI 3(+)-card raise)
2
♠-2NT; (2
♠ natural, explained upthread. 2NT natural, showing a balanced hand)
3
♣-3
♦; (confirming the 3=5=4=1, showing the diamond support)
3
♥-3
♠; (waiting, spade control - which must be the ace because of the balanced hand)
3NT-4
♣; (Nonserious 3NT, club control and slam interest opposite a nonserious hand)
4
♥-4
♠; (Signoff - I don't like bidding 4
♦ Last Train here when partner has shown diamonds, 4
♠ shows the diamond control and a hand that doesn't want to take charge)
4NT-5
♣; (RKC 1430 for hearts, 4 key cards)
5
♥-6
♦; (King ask, confirming all key cards and the
♥Q, 6
♦ shows the
♦K and denies
♣K and
♠K)
?
And now I'm not sure what South does. There are likely 12 tricks on top - 2 spades, 5 hearts, 1 club and 4 probable diamonds even without knowing of the
♦J. We can likely ruff a club in hand in 7
♦, but in the absence of the
♦J this contract might depend on a 3-2 diamond split, which is 'only' 68%. However, there is room to ask for more information with either 6
♠ or 7
♣. The normal rule is to bid the grand in which you have the jack. The problem is that we can see that partner doesn't have the
♥J as we have it, so we might end in an inferior 7NT when 7
♥ was cold. In theory we should use 6
♠ and 7
♣ to clarify which jack we are looking for, but I don't have such an agreement - only that 6
♠ asks for more information (here focusing on the
♠Q) while 7
♣ asks for the red suit jack. Blasting 7
♥ also isn't safe - if North has a 3=3=4=3 or even 4=3=4=2 we might depend on a black suit sqeeze or finesse for that 13th trick, and that's assuming the diamonds run. I am not sure what I would do here - it's probably with the odds to pass the buck to partner with 6
♠, and hope partner can sqeeze out 7
♦. Tricky.
It might be fun to consider how it would continue if North decides to take the reins over 4
♥:
[..];
4
♥-4NT; (RKC 1430 for hearts)
5
♣-5
♦; (1, asking for the Q)
5
♠-6
♦; (
♥Q +
♠K + neither
♦K nor
♣K, asking for
♦Q);
7
♦-? (
♦Q)
I did not see this coming and would not have bid this way at the table, but this is much easier!