♠ A 8 6 4 2
♥ 9 8 7 6 5
♦ A 6
♠ K Q J 7 3 ♠ 10 9 5
♥ K 4 ♥ J 10 3 2
♦ K 9 5 ♦ J 10 7 4 2
♣ Q 4 2 ♣ 5
♥ A Q
♦ Q 8 3
♣ A K J 10 8 7 6 3
South opened 1♣, West overcalled 1♠, North made a negative double, East passed and South rebid 5♣!
West led the ♠K. Declarer won the ace and discarded a diamond. He led two rounds of trumps and East showed out. South led a third round. After ruffing the spade return, declarer led a diamond to the ace, took the heart finesses and was down one.
Suppose South was your partner. After the game, while running the boards, he complained about his luck and asked you if he could do better. What would you tell him?
A better play might be to discard the ♥Q at trick one. Then continue with ♦A and another. If East wins, your ♦Q is good. If East plays low, you play the ♦Q and West is in with his king. What can he do? If he leads a trump, your club loser disappears. If he leads a plain suit, you can ruff the diamond in dummy. You make the contract, losing a diamond and a trump. This line works against almost any reasonable distribution.
Do you notice anything else? South can also make the contract via an endplay. He can run all his trumps, keeping ♥A Q and ♦Q 8 in hand and ♦A 6 in dummy. West has to keep K-x in both red suits. Then declarer can play ace and another of either red suit and West is endplayed.
The second line requires more to make the contract, but isn't unreasonable. Cute hand.