In yesterday's column, I mentioned that if you never double a making contract, you are not doubling often enough. But having said that, I should add that there are times when making a penalty double of a contract you can beat is inadvisable.
    Although North had only four low spades, he had 15 high-card points, two support points (one for each doubleton) and only six losers. This made his hand worth a three-spade rebid.
    South was now thinking about a slam, but what about hearts? It was unlikely, but the opponents might have been able to cash the ace and king. South control-bid (cue-bid) four clubs to show his club ace and express slam interest. North, who could "see" five club tricks, was happy to show his heart ace. South launched Blackwood before bidding seven spades.
    Now East probably should have passed, hoping his partner would find a club lead. But he made a Lightner Double, asking for a lead in the first suit bid by the dummy.
    South, taking the hint, ran to seven no-trump.
    West led the diamond jack. South won in his hand and cashed the spade ace, seeing West discard. Declarer crossed to the board twice with a heart to lead spades through East and make his grand slam.
    Be wary of doubling the only contract you can beat.