I don't like starting negative double with the north hand. So I fall into the 2
♥ bidding group.
One might first, however, consider this auction...
Pass - (1
♠) - 2
♠
2NT - 3
♦
4
♦ - 4
♠, 4
♠ mild slam try,
6
♦ - East is great for a slam try given a passed hand
But, ok, I admit I would open south 1
♣ as well. After bidding 2
♥, forcing, South does have a problematic rebid.
- 2♠ would probably show support, if not and it was waiting I would bid that, but for me it is "good support",
- 2NT would show a spade stopper,
- 3♣ a fifth club,
- 3♦ diamond values, but probably no longer a reverse, the question is would it promise a real suit, in which case it mis-identifies two cards in the hand (suggesting 45 in the minors, when really 34). So South has a real problem. (If 3♦ just shows concentration of values and inability to bid raise hearts or bid 2NT, then the auction is easy, but who plays that?)
Here is a reasonable auction with opponents passes not shown, with a curious Bluhmer cue-bid thrown in for good measure.
1
♣ - (1
♠) - 2
♥
3
♣ - 3
♦ The 3
♣ bid only misidentifies one card, Not a spade stopper, not heart support, a "fifth" club.
3
♥ - 4
♣
4
♠! - 5NT
6
♦ - pass
This auction, however if full of problems. The 3
♦ bid is natural and forcing, the 3
♥ is doubleton (most likely honor doubleton). The 4
♣ is bidding out shape, and possibly finding correct strain of clubs. 4
♠ has to be a Bluhmer cue-bid (Opener has denied spade stopper not once but twice), showing all his values outside of spades. 5NT is pick a slam, obviously implying good diamonds and only three card club support. But the problem is, opposite five clubs, North might just bid 6
♣ which isn't a great spot instead of offering up a choice. If given a choice, South will suggest diamonds, obviously.
Blue moon rising -- CR ccr