Whew


6
A Q 10 9 5 4 3
10 9 6 2
2
Q 2 9 8 5 3
8 7 6
A K Q 4 J 7 5 3
K 10 9 6 5 3 J 8 4
A K J 10 7 4
K J 2
8 Vul: No one
A Q 7 Opening lead: K of diamonds

SouthWestNorthEast
1 2 Dbl 3
4 5 6 Pass
Pass Dbl Pass Pass
6 All pass
Well, yes, declarer can and (in the printout I have) did drop the doubleton queen of spades for as many points as any undoubled declarer in 6 hearts would make. How declarer knew to go for the drop, I guess we'll never know. But it's easy to see how much safer the more balanced suit would have been. Six hearts wouldn't be an easy contract if we give the Q of spades to the four-card holder (where 6 spades couldn't make). Still he should prevail, thus:
Cash a spade (on a diamond opening and continuation) and ruff one high, trump to the K, ruff a spade high, back to the J of trump and now with only the Q out (on my hypothetical 4-card holding with the Q), declarer can drop it and sluff two diamonds, all that remain. So he has an extra entry here, though the careless declarers who take two heart leads before asking what to do next are going to have unhappy partners. On a club opening lead, you have a chance for an overtrick. One of dummy's diamonds goes on the second club honor, so you'll only need to sluff 3 on the spades, which should be easy in a heart contract: cash the ace of spades, ruff high, back with a trump, ruff high. That's your limit. That is to say, you've only three spades left, and if you haven't dropped the Q, you'll have to ruff one more spade and so won't be able to sluff three of them. You'd have to ruff a spade and lose a diamond, so as to ruff the second round in the closed hand and then sluff two on the spades.
But all this is academic. The Q falls on the second round and if you don't get a diamond lead, you can sluff all of dummy's diamonds. I only wanted to show how safe the 6-heart bid is even if either opponent holds the Q with 3 kickers.
It's so obvious that hearts would work better (by and large) and the heart suit itself isn't all that balanced, that I dickered about whether I wanted to chat this hand up -- until I saw the bidding! And that did it. It's really a matter of two other basic principles in bidding more than of the balanced suit for trump, first trust your partner (or at least bid as if you do), and secondly there is the stupendously good fit. How can you turn your back on a 10-card fit for a 7-card?
Oh, South didn't know his partner's heart suit was that good? Oh, come on. North introduces a suit at the six level that at best is headed by the A Q 10, and South doesn't know he's got good enough support? Further, if that isn't enough, he accepts the bid until his LHO doubles! And he get scared and runs! Oh, come on, please. You don't trust your opponents to steer your right1 N-S bid and made a slam on a lucky break and got 57%! With the double, they almost surely would have been in the 90's. A redouble probably would have brought them 100%.
[a later comment] I hate that, running from an agreed-upon contract on an opponent's double. You decide where your best spot is, that is you and your parnter. If an opponent doubles, well, it seems to me that there are three possibilities, to wit: (1) He made a bad double, as above, and as not too rarely happens. (2)His double is valid and will hold up, but you do not have a better spot. (3)And lastly, he's disclosed valuable information that enables you to find a better spot. With the possible exception of running from a trump slam to no trump if I'm sure all suits are stopped with high cards, I would take my chances on the first two possibilities. Always. You can't let those guys jerk you around.