N/S vul, dealer W
What does South bid?
Without a good distribution, I will just have to pass with this hand. The hand isn’t exactly that great anyway, and the defence (you and partner) rate to take this contract down as partner is marked with heart length (if East had heart support, he will often raise to 4♥).
Partner shouldn’t have a powerful hand since he didn’t act over the 3♥ opening bid, so be glad to defend 3♥ rather than guess which contract to declare (and probably go down!), particularly if we have to play at the four-level (or 3NT without enough high cards).
I assume you would also pass if nil vul.
As you could probably guess, we missed 3NT (and 5♦).
Partner actually had
Opposite my hand:
My friend said I should have doubled (as South in the balancing seat) in case partner has above hand, or has a trap pass hand?
Any takers for ultra-aggressive immediate 3NT by North?
Yes, I would also pass if not vulnerable.
I think your partner should (probably) overcall 3NT. It’s not perfect, but with 15 points and hearts controlled with a potential source of tricks in diamonds, you might just have to take the chance and bid 3NT. It’s definitely not an automatic call, but it’s one of those situations where “it’s dangerous to bid, it’s dangerous to pass” – and when faced with this dilemma, I usually opt for the aggressive option and bid!
What I’m 100% sure of is that your hand is definitely a pass. We can’t double “just in case partner has this hand” – chances are, there is much more downside to doubling – for example, partner bidding 3♠, or 4♠ (since we have practically promised four spades), or partner could have around 9-11 points (which is most often the case in this type of auction) and bids 3NT and we go down a lot.