The bidding: South, with 13 HCP’s, opens One Heart, and North bids a forcing One No Trump, denying four Spades and four Hearts. South cannot rebid his four-card second suit, Spades, because that would be a reverse showing 16+ HCP’s. A reverse shows an Ace above an opening if partner could have as few as six to nine points. Therefore, he must bid a three-card Diamond suit. Had he been two-two in the minors, he would have rebid Two Clubs.
If opener rebids a minor after a forcing No Trump over his One Spade, it shows three cards.
North was originally intending to bid One No Trump then Three Hearts, likes the Two Diamond response and therefore bids Four Hearts.
The Play: West has a natural lead, top of a touching three-card honour sequence. If his Club suit was KJ10xx, West would have a lead problem, perhaps the Club Jack. Doubletons are lousy leads and both West’s doubletons are suits bid by his RHO. These are terrible leads, but the worst lead would be Ace without holding the King as well. However, he has no problem with the Club Queen. Queen from QJ10xx is excellent, Queen from QJ9xx is okay, and Queen from QJ7xx is okay in a pinch.
Declarer wins the Ace and plays the Heart Ten. East ducks smoothly and declarer lets it ride. He wants to protect his Spade King and keep East off of lead. East, no question, would put the Spade Queen on the table once on lead.
The Heart Ten holds and declarer continues with the Nine. He draws all the trump and runs his Diamonds, pitching his three Spades. Declarer will make 12 tricks for +680. If he does not take the deep heart finesse, he will only make ten tricks. He still makes his contract, but it is a poorly-scoring board.