A reader wonders what percentage of my readers play in duplicate tournaments. My guess is 10 percent. Most readers of newspaper bridge columns are casual players. The U.S. has millions of players, but the membership of the American Contract Bridge League, which oversees tournament play, is 166,000. Nevertheless, duplicate players are prone to study the game's techniques intensely, so my estimate may be low.

Social players who try duplicate often fail to understand that their score on each deal matters only in relation to what other pairs did in the same deal. In today's deal, North-South get to 3NT, and West leads a heart. Declarer puts up dummy's queen, winning.

At rubber bridge, party bridge, or IMPs, the goal is to make the contract, so South forces out the ace of spades next. He is sure of two spades, two hearts, three diamonds, and two clubs.

At matchpoint duplicate, making the contract is not the goal (as strange as that may sound). South wants a higher score than the other Souths. The contract is normal. Every North-South will get there, and every South will presumably get the same opening lead. If South takes nine tricks when everyone else takes more, North-South will get a bottom score.

So South must adopt the play that will usually win the most tricks. At Trick Two he leads a low club from dummy. East wins and returns a heart, and South takes the ace and runs the clubs for at least 10 tricks. If the clubs broke 4-1, South might go down, but he would have played correctly.