West   North   East   South
                                 1♥
pass     2♦¹      pass   2NT
pass     3♥       pass   3♠²
pass     4♣²     pass   4NT³
pass     5♦⁴      pass   6♥
all pass

1 - 2/1 is forcing to game
2 - cue-bid
3 - RKC Blackwood
4 - 1 or 4 keycards

You are East on this defensive problem. The opponents reach 6♥ after an uncontested auction. Partner leads the ♠5, declarer captures your queen with the king. A heart is then led to dummy's nine. What should you return after winning this trick with the ♥J to defeat the contract?
Solution:
The question we asked you was what should you return after winning this trick with the ♥J to defeat the contract. This was a trick question of sorts, because the contract will be made once you win the trick with the ♥J! Declarer, who is marked with a five card heart suit both from the bidding and his tackling of the suit, will be forced to play you for the ♥K. The key play is to capture the ♥9 with the ♥K at trick two. Declarer, who now "knows" that partner has the ♥J, will subsequently play a heart to the ten, allowing you to make a trick.

It is worth noting that declarer's play in the heart suit was flawed - the double finesse (running the queen first, and running the ten if the queen lost to the king) is a better bet.

Analysis:
The hand hinges on the heart suit, and the double dummy analysis does not tell us anything that we don't know.
Par Contract Analysis:
The par contract on this deal is 6NT by North-South.

Bridge Baron deal No : N3828-86124-99537-93326-89474-08925