Werner Karl Heisenberg said, "An expert is someone who knows some of the worst mistakes that can be made in his subject, and how to avoid them."

Did you see the play "Copenhagen," in which the playwright, Michael Frayn, claims that Heisenberg purposely derailed the German attempt to build a nuclear weapon in World War II? Was that true?

In this four-heart contract, it would be difficult to avoid a losing line of play. What should South do after West leads the spade king?

North's four-diamond response was a Texas transfer.

Most players would win with the spade ace, draw trumps ending in the dummy and run the diamond 10. West would take the trick and shift to a club. Declarer would win with dummy's ace and take a second diamond finesse, then grumble when it also lost: down one.

An expert wonders if there is a way to execute an endplay. To do that, he has to eliminate the pointed suits without East's taking a trick and shifting to a diamond. How?

The key is to let West take the first trick. Suppose he reads partner's spade two as a suit-preference signal for the lower-ranking side suit and switches to a club. Declarer wins, draws trumps ending in hand, discards a club on the spade ace and pitches dummy's last club on the spade jack.

West wins and leads a club (best), but declarer ruffs high on the board, crosses to his hand with a trump, ruffs his last club and runs the diamond 10. West is end played, forced either to return a diamond or to concede a ruff-and-sluff.