Neither side vulnerable.  
South deals.
                              NORTH
                              S: Q 4 2          
                              H: A           
                              D: Q J 10 9 7 3
                              C: J 5 3   
            WEST                             EAST
            S: 9 7                           S: J 10 5 3   
            H: K Q 10 9 4 3                  H: J 7       
            D: K                             D: 6 5 4             
            C: K 8 7 4                       C: 10 9 6 2    
                              SOUTH                         
                              S: A K 8 6
                              H: 8 6 5 2    
                              D: A 8 2   
                              C: A Q      
                  SOUTH    WEST    NORTH    EAST                  
                   1NT     Pass     3NT     Pass
                   Pass   Double  (All Pass)
            Opening Lead: KH	
     This hand is a perfect example of the strange game we call	
match point duplicate bridge.  If you saw all of the cards you
could bid and make six diamonds.  If all you could see were the
North-South cards you might still bid six diamonds because you
would only need one of the two minor suit finesses to work to
make the contract.  This would be a seventy-five per cent
probability.
     The problem is that once you start investigating for the
diamond slam you may decide that you want to stop in game and if
you are beyond three no trump (in the bidding) you may wind up in
five diamonds.  If you can make twelve tricks in diamonds your
score would be +420.  If you make only ten tricks in no trump
your score would be +430, so you are punished for winding up in a
diamond contract.  Because of this, it is very difficult to bid a
minor suit game or slam when three no trump is even a slim
possibility.
     In the hand shown, West decided to double three no trump. 
Barbara Greenspan of Beachwood was the declarer and the opening
lead was the king of hearts.  She won the opening lead in dummy
and stopped to consider why West would double what appeared to be
a pretty solid contract.  The only logical conclusion was that
West had a long heart suit and the two minor suit kings.  If that
was the case, there was only one way to play the hand. 
     Accordingly, Greenspan called for the three of diamonds and
when East played low she put the ace on the table.  The king of
diamonds fell under the ace and the contract was made with two
over tricks for a top score.
     There are two important points here.  1.  Do not double a
contract when that double could draw a road map for declarer. 
The exception to this is that it is permissible to double when
the road map doesn't matter.  2.  As declarer, listen to the
auction and read any road maps provided by the defense.  At
times, you may be required to determine if the road map provided
was really a true map or a devious detour that should be avoided. 
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