Contract Bridge

Obviously, a declarer should avoid a finesse that can’t gain when it succeeds and can prove very costly if it fails. The principle is selfevident, but just when to apply it is not always easy to recognize.

South bid aggressively to reach six hearts, and West led a diamond. Declarer finessed the queen, losing to East’s king, and later went down one even though the club finesse succeeded. Had South put up the ace of diamonds at trick one, drawn trump and taken the club finesse, the outcome would have been entirely different. South would have been able to discard his diamond loser on dummy’s fourth club, so his only loser would have been a spade.

When declarer’s play is analyzed, it becomes clear that he erred by taking the diamond finesse at trick one, since it could not help him make the contract. Even if the finesse had won, South would still not have been any closer to making the slam.

Before deciding how to proceed at trick one, South should consider what is required to succeed. Since a spade loser is unavoidable, it becomes obvious that South cannot make the slam unless the club finesse works. And if the club finesse succeeds, South does not need to try the diamond finesse. The diamond finesse therefore poses an unnecessary risk since it jeopardizes the slam without improving the chance of making it.

The only time the diamond finesse gains in any way is when West has the king of diamonds and East has the queen of clubs. In that case, declarer saves a trick by going down one instead of two, but this is an insignificant consideration when making a slam is at stake.