Contract Bridge

Assume you’re in three notrump and West leads a heart. You can’t very well afford to win East’s jack, since West might have another heart, so you duck.

East now shifts to the ten of spades. There’s nothing to be gained by taking the finesse, since West is marked by the bidding and play with the K-J of spades. So you go up with the ace in order to retain the guarded queen.

You then play the king of clubs, taken by West with the ace.

If West now returned a spade or a diamond, you’d have nine ironclad tricks. Unfortunately, though, he returns a club, leaving you with just eight tricks.

To make the contract, you need to score four diamond tricks, but you can’t be sure of getting them by simply playing the A-Q-K, since the jack might not fall.

However, there’s no need to tackle the diamonds yet, so first you cash your three club tricks and the ace of hearts. Now comes the A-Q and another diamond, and when East produces the nine, you have reached the critical point of the play.

Should you finesse the ten of diamonds, hoping East has the jack, or should you go up with the king, hoping West has the jack? You are home safe and sound if you guess right, but how can you tell which is the winning play?

The answer is that you can guarantee the contract by playing the ten. If the ten wins, you have nine tricks, and if the ten loses, you also have nine tricks! In the latter case, since West can’t have any more hearts, diamonds or clubs after he takes the jack of diamonds, he would have to concede a trick to your queen of spades and thereby hand you the contract.