You are East, playing the last board in a closely contested team-of-four knockout match. South opens 1♦, partner overcalls 1♥ and North bids 2♦. You try 2♠, as 4♠ would be an excellent contract if partner has spade support. South goes into a tank, and finally bids 5♦, partner and North pass. This is not an enviable situation to be in. Partner is likely to lead spades since you bid the suit, which might not augur well for the defense. You double, hoping it might alert partner not to lead a spade.

Partner apparently did not get your message, and makes the disastrous lead of the ♠K. Declarer wins the trick with the Ace, and leads a diamond and captures partner's King with dummy's Ace. Declarer leads the Queen and Jack of spades, and discards the Ten and King of hearts. He then calls for a low diamond from dummy. Do you give up, or can you think of a way to beat the contract?

Solution:
Declarer calls for a low diamond from dummy, and you should play the ♦Q since playing a low diamond is pointless. The real question is what should you play after winning the ♦Q. The ♣10 is the most intuitive play. If partner holds the ♣A, it will net a club ruff. Another option is to exit with the last diamond, on the general principle that one trump of yours will take away two of the opponent trumps.

Before making a decision, let us take stock and try to count South's hand. He has 1 spade, 2 hearts (assuming the ♥10 and ♥K are true cards), 5 diamonds, and therefore has 5 clubs. If partner has 2 natural club tricks, then the contract is always set. If partner has one quick club trick, declarer threatens to give up a club trick and ruff a club to establish the suit. You can put an end to this plan by attacking declarer's entries in hand, so that he does not have the entry to enjoy the established club. The way to do it is to play a heart, making declarer ruff in hand. After this defense, declarer will succeed whenever clubs are 3-2, but will fail on the actual lie of cards.

Analysis:
Bridge Baron's double dummy solver points out that the ♠K is the only card to let declarer make the contract. After declarer wins the ♠A, he has to cash a club honor before playing a diamond to the Ace. Then he can discard his two hearts on the Queen and Jack of spades, and lead a club towards his hand. Even you could not defeat the contract then. On the actual line declarer took, making him ruff hearts in his hand to kill the club suit is required to defeat the contract.
Par Contract Analysis:
The par contract is 4♦ by North-South.

Bridge Baron deal No : N1938-44704-68573-45798-15634-21412