An elimination play can save many a contract. Its purpose is to force a defender, usually near the end of play, to make a play disadvantageous to his side.

Here is a simple illustration. South is in four spades, and West starts by leading three high hearts, declarer ruffing the third.

South now leads the queen of spades, on which West plays the five. It would be wrong to finesse the spade in view of West’s weak two-bid, which he would scarcely make if he had the guarded king of spades as well as the A-K-Q of hearts.

So South goes up with the ace of spades, hoping to catch the singleton king, and also planning to develop an endplay against East if the king does not fall.

When the king does not appear, South proceeds with his second plan. He cashes the A-K of diamonds, eliminating that suit from the dummy and his own hand, and then throws East on lead with a spade.

East cannot afford to lead a diamond, which would allow South to ruff while discarding a club from dummy, so he returns a club. Declarer wins the club in dummy (with the nine or jack, depending on what West plays) and then takes another club finesse to make the contract.

Note that if South takes the spade finesse, he goes down. East would be able to exit safely with a spade or a diamond, and East-West would eventually score a club trick with proper defense.

Oddly enough, the contract can be defeated by an unusual play. If East foresees the impending endplay, he can thwart it. All he has to do is to trump the third heart lead with the king of spades — even though he is trumping his partner’s high heart — and then return anything but a club. Against this defense, declarer is helpless.

Tomorrow: Bidding quiz.