Fit Jumps Opener has 5422 Hand 4

Board 4 North Deals	♠ A K 6 4 ♥ K J ♦ A 10 9 8 2 ♣ Q 3
♠ 8 7 ♥ 9 7 6 4 ♦ 5 3 ♣ K J 10 9 6	N W E S	♠ 10 3 2 ♥ Q 8 3 2 ♦ J 6 ♣ 7 5 4 2
	♠ Q J 9 5 ♥ A 10 5 ♦ K Q 7 4 ♣ A 8

West	North	East	South
	1 ♦	Pass	2 ♠
Pass	3 ♠	Pass	3 NT
Pass	4 ♦	Pass	4 NT
Pass	5 ♦	Pass	5 NT
Pass	6 ♥	Pass	7 ♠
All pass

7 ♠ by South

Lead: ♣ J

Made 7 — NS +1510

After the fit jump north shows 12-16 points and not singleton or void with 3 ♠. South's 3 NT shows slam interest opposite 15-16. Possibly that is an underbid here as there is a slam opposite as little as ♠ AKxx ♥ xx ♦ Axxxx ♣ xx.

North's 4 ♦ is very descriptive. There is a lot of information when extra values are shown and a cue is denied in a suit. For example here to get to 15 hcp with nothing in clubs south can imagine ♠ AKxx ♥ Kx ♦ AJxxx ♣ xx - remember that with 15-17 points opener must be semi-balanced. Therefore south can see a potential grand slam immediately. Of course there is the potential for a worse hand with no ♥ K and or with the ♣ Q etc. But the point is 4 ♦ is incredibly revealing and encouraging.

Roman key-card Blackwood reveals three key-cards and as south can imagine the grand opposite the ♥ K then bids 5 NT to promise all of the key-cards. When north shows the ♥ K the grand is bid.

Notice how the ♣ K is not nearly so useful as only one of south's hearts can be pitched on the long diamond.

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