[robertb]

Dealer: South
Vul: E/W
Scoring: IMP
♠ AKJ
♥ AT73
♦ J82
♣ K54

♠ QT83
♥ K5
♦ KQT73
♣ A6

It seems to me that this one comes down to a question of cue-bidding style and agreements. If you bid aces before kings, you'll very likely play in 3NT; if you make the cheapest cue-bid, you may reach 6NT.

I can certainly imagine reaching 6NT playing 2/1:

1D - 1H
1S - 2C (4SF)
2D - 3D
3H - 3S
3N - 4C
4D - 4S
5C - 5H
5S - 6N

The first 3 rounds of bidding seem normal enough to me (although 3 diamonds might not be a popular decision); 3 hearts is what my regular partner and I would cue-bid on this hand, which promises that there's at least one more cue-bid available (which can be a strong feature in diamonds, such as AK, AQ, or KQ), and 3 spades is forced.

3NT is to play; but I think it's reasonable to make another bid on that (pretty wonderful) collection of north cards, and obviously it's going to be 4 clubs, to leave as much room as possible for partner to cue-bid out his hand.

Four diamonds shows a diamond cue bid and a maximum. I'd like to think I'm a good enough bidder to cue-bid the spades over the hearts in response, as, holding AKJ opposite partners four card suit, I might want him to be able to show the queen eventually, and I know that it's not going to cost partner a bid, as he can't possibly be wanting to cue-bid spades.

Five clubs is pretty much forced on opener next, who has a rapidly improving maximum for the 3NT bid.

Knowing that partner has no round suit losers and likes his diamond suit, I think it's got to be right to bid some slam, so I'm comfortable committing to one with 5 hearts. I can certainly imagine that it depends on the diamonds not blowing up and a spade finesse - but I feel committed at this point.

Opener now can bid 5 spades to show the next round of control in spades.

And now responder can see that we have as many tricks in NT as in diamonds -- we just have to hope that the number is in fact 12.

[FrancesHinden]

I think this is a difficult hand to bid, and I'd be quite happy to get to 6D even though 6NT is better.

By the way, if this is from round 2 of the Rosumblum, then they aren't all "world class" players: there is open entry to the event.