Stop their four and end with 10

Claude Debussy said, “Music is the arithmetic of sounds as optics is the geometry of light.”

Bridge is the arithmetic of tricks. If your opponents take four tricks, it is very difficult for you to win 10! Bear that in mind when playing in four of a major.

Today's deal is an example. West leads the diamond four against South's four-heart contract. What should declarer do?

When North raised to two hearts, South made a help-suit game-try in his weak suit. If North had club losers, South wanted to stop short of game. But North liked his king-doubleton, so jumped to four hearts.

This ought to have persuaded West to lead the club jack, which would have defeated the contract, assuming East shifted to a diamond after taking two club tricks.

Note also that if North had advanced with one spade and reached four spades, that could have been defeated after an initial diamond lead.

South sees 10 tricks: four spades, five hearts and one diamond. Fine, but he should also worry about losers. He might concede one spade, one diamond and two clubs; surely East has the club ace over dummy's king. However, if declarer will lose two club tricks, West must get on lead to shift to the suit. To stop that, South just has to duck the first trick, letting East take the trick with his jack. (He plays the jack to find out who has the queen; he knows West is not underleading the ace.)

South wins the diamond return, draws trumps, takes the spade finesse and makes his contract.