A pre-emptive bid may greatly inconvenience the opponents. Take, for example, this deal. With neither side vulnerable, South opens one diamond, and West throws a monkey wrench into the works by jumping to four clubs. What should happen after that?
Perhaps your immediate reaction is that North should make a penalty double. Here, because declarer cannot get into the dummy to play a heart toward his king, the contract would go down three, minus 500. That is more than a nonvulnerable game, but not as good as a slam.
Also, it is rare that the responder will have a penalty double. It is much more likely that he will have a hand with no long suit and no great diamond support but too many points to pass. That is what a double ought to show — what we call convertible values.
Then, the opener passes with a balanced hand, or bids with an unbalanced collection, confident that some useful cards will appear in the dummy. Here, South might leap to six diamonds. Or, if he settles for five diamonds, North might raise.
Against six diamonds, West leads the club king. How should South plan the play?
Declarer has 12 top tricks: three spades, one heart, seven diamonds and one club. But there is a natural instinct to try to win trick one with dummy's club ace. Unlucky! East ruffs the ace and shifts to a heart, killing the contract.
To ensure those 12 tricks, South should play a low club from the board at trick one. And if West continues with the club queen, declarer ruffs in his hand, draws trumps, and claims.
Perhaps your immediate reaction is that North should make a penalty double. Here, because declarer cannot get into the dummy to play a heart toward his king, the contract would go down three, minus 500. That is more than a nonvulnerable game, but not as good as a slam.
Also, it is rare that the responder will have a penalty double. It is much more likely that he will have a hand with no long suit and no great diamond support but too many points to pass. That is what a double ought to show — what we call convertible values.
Then, the opener passes with a balanced hand, or bids with an unbalanced collection, confident that some useful cards will appear in the dummy. Here, South might leap to six diamonds. Or, if he settles for five diamonds, North might raise.
Against six diamonds, West leads the club king. How should South plan the play?
Declarer has 12 top tricks: three spades, one heart, seven diamonds and one club. But there is a natural instinct to try to win trick one with dummy's club ace. Unlucky! East ruffs the ace and shifts to a heart, killing the contract.
To ensure those 12 tricks, South should play a low club from the board at trick one. And if West continues with the club queen, declarer ruffs in his hand, draws trumps, and claims.