Remember, the enemy is eavesdropping
Bridge bidding is, of course, a conversation. You are trying to tell me what is in your hand, I am trying to tell you what is in mine, and as the talk gets more explicit we both wish we could have some privacy. Unfortunately every word is being overheard by our enemies, and this causes trouble. Consider the Blackwood convention, which is one of the best slam-bidding systems because it reveals so much information to the bidders. Alas, it can also be one of the worst of systems because it may alert the opponents to a profitable double that they could not otherwise risk. The hand below, played during one of the team matches on my recent Orient bridge cruise, illustrates the point.
I am a cautious fellow, and it is my theory that it seldom pays to double a slam that the opposition has arrived at voluntarily except as a call for an unusual lead that might be the only way to set the hand. Yet here I was, as West, doubling a slam the opponents had bid with apparent confidence—though my hand could certainly take no more than one trick. The reason for the double was the enemy's Blackwood bidding, which told me too much.
I now knew that my king of spades was safe, because North's five-club response to Blackwood denied holding an ace. My partner must have an ace, because if South had held all four of them he would have continued his Blackwood sequence with five no trump to ask his partner about kings. Similarly, South did not have a void suit, because with a void he would not have used the Blackwood convention. Further, since South must know there was danger of losing two tricks, my double could not be answered with a redouble. Thus there was no possibility of a large loss, even if I failed to find the right opening lead and declarer somehow managed to get rid of his loser in the suit in which my partner held the ace. Finally, there was the chance that declarer might believe my double to be based on something more than logic and might play me for a vital card actually held by my partner.
My heart opening lead did not find partner's ace, but declarer had to give me a trick with the king of spades, and then my diamond lead enabled partner to collect his trick. South was able to trump the second diamond, but he still had to find the queen of clubs. By this time South knew that I did not have to hold the club queen to justify my double, but he decided the odds were I held the queen. The result was a two-trick set worth 500 points.
South was unlucky to misguess the club, to find the king of spades offside and his partner with a worthless king. But he would have escaped at much lower cost if he had bid the slam without checking up on aces. The Blackwood bid was unnecessary, since he had decided to bid six even if an ace was missing, and he could hardly hope to find North with enough to make a grand slam possible.
At the other table our teammates reached the same slam, but without using the Blackwood sequence. They did not make the slam either, and South did not guess the clubs any better. But by refusing to talk about aces in front of eavesdroppers, they saved 300 points.
ILLUSTRATION
Both sides vulnerable South dealer
NORTH
[Queen of Spades]
[Jack of Spades]
[10 of Spades]
[6 of Spades]
[Queen of Hearts]
[8 of Hearts]
[4 of Hearts]
[King of Clubs]
[Jack of Clubs]
[10 of Clubs]
[3 of Clubs]
[King of Diamonds]
[9 of Diamonds]
WEST
[King of Spades]
[4 of Spades]
[7 of Hearts]
[6 of Hearts]
[5 of Hearts]
[8 of Clubs]
[7 of Clubs]
[4 of Clubs]
[Jack of Diamonds]
[6 of Diamonds]
[5 of Diamonds]
[3 of Diamonds]
[2 of Diamonds]
SOUTH
[Ace of Spades]
[9 of Spades]
[8 of Spades]
[7 of Spades]
[5 of Spades]
[Ace of Hearts]
[King of Hearts]
[Jack of Hearts]
[10 of Hearts]
[Ace of Clubs]
[9 of Clubs]
[5 of Clubs]
[10 of Diamonds]
EAST
[3 of Spades]
[2 of Spades]
[9 of Hearts]
[3 of Hearts]
[2 of Hearts]
[Queen of Clubs]
[6 of Clubs]
[2 of Clubs]
[Ace of Diamonds]
[Queen of Diamonds]
[8 of Diamonds]
[7 of Diamonds]
[4 of Diamonds]
SOUTH
1 [Spade]
4 N.T.
6 [Spade]
PASS
WEST
(Goren)
PASS
PASS
DOUBLE
NORTH
3 [Spade]
5 [Club]
PASS
EAST
PASS
PASS
PASS
Opening lead: 7 of hearts