Beware of the vulnerability.
Bridge Column for March 1, 2002, Harvey Bernstein
North-South vulnerable.  North deals.
                              North
                              S: 9 8 7 4 3        
                              H: Q 7 4       
                              D: J           
                              C: A J 4 3 
            West                             East
            S: 10 6 5 2                      S: Q J          
            H: K 8 5 3                       H: A 10 9     
            D: A 6 5                         D: Q 10 9 8 7        
            C: K 2                           C: Q 9 8       
                              South                         
                              S: A K  
                              H: J 6 2      
                              D: K 4 3 2   
                              C: 10 7 6 5 
          The Bidding:  
                  North    East    South    West                  
                   Pass    Pass     1D      Pass
                   1S      Pass     1NT     Pass
                   Pass    Pass
     Many years ago, when I was first learning how to play this
game, my Uncle Mike (Myron Rothman of Toledo), taught me that it
was important to recognize the differences that vulnerability
created.  Well, it has been many years since Uncle Mike passed on
to his reward, but if he were alive today he would be looking
directly at South and saying "I told you so!"
     South could easily argue that he had two and a half quick
tricks and therefore was within his rights to open the bidding. 
While my Uncle and I would disagree, many players would feel
comfortable making this call.  Our differences become much
greater when the auction comes around to South again.  He is
clearly walking on thin ice to rebid one no trump.  He may only
hold two spades, but they are very good spades.  If the
opposition can get into the bidding over one spade, so be it.  He
has done all he could reasonably do and maybe more.  
     After a pass by South, West will be hard put to balance and
one spade should become the final contract.  North will struggle
but his spade length should help him score seven tricks, and
maybe even eight.
     Against one no trump, West led the three of hearts.  East
won the ace and decided to go after diamonds.  He played the
queen, smothering North's jack.  Declarer played low and West
played the six.  The ten of diamonds came next and for some
reason, South played the king.  He would have been so much better
off to duck until he could not duck anymore.  West won the ace
and returned a diamond.       
     It got pretty ugly after that and declarer took only four
tricks.  Minus 300 was not a good score.  
     My partners and I usually make an agreement about opening
light.  If either of us is in third seat, and not vulnerable,
there are no restrictions on opening the bidding.  That changes
when we are vulnerable.  In that case, we require a real opening
bid.  And when we do open light (not vulnerable), we don't take a
second bid unless we are forced to do so.  It's a good rule to
follow.
_______________________________________________________
Bernstein is a free-lance writer in Solon.