How would you interpret South's bid of five spades?
A voluntary raise to five of an agreed trump suit may have various meanings. It may direct partner's attention to the trump suit, asking him to bid six only with good trumps. It may be a general slam try, asking him to decide based on overall strength. It may ask him to go to slam if he has a control - the ace, king, singleton or void - in the only unbid suit.
In today's auction, South meant his raise to five spades to show slam interest with controls in both unbid suits.
At six spades, South took the ace of trumps at the second trick. He'd lose two trumps only if West had K-J-7 - an 11 percent chance - but that was how the cards lay.
South can play safe for one trump loser but doesn't know whether he can afford the safety play: If West has the king of hearts, South must pick up the trumps without loss. So at Trick Two South should let the queen of hearts ride. If the finesse lost, he would later cash the ace of trumps.
When the finesse wins, South leads a club to his hand and returns a low trump. When West plays the seven, South covers with dummy's ten and can lose no more than one trump.
If West had the king of hearts and J-7 of trumps, he could duck the first heart, inducing South to play safe in trumps when he actually couldn't afford to do so.