East-West vulnerable.  
South deals.
                              North
                              S: A                
                              H: A 4         
                              D: K J 6       
                              C: A 9 7 6 5 4 2
            West                             East
            S: 10 9 7 4 3                    S: Q J 5 2      
            H: Q 8 7                         H: J 10 9 3   
            D: A 7 5 4                       D: 10 8 3            
            C: J                             C: 10 8        
                              South                         
                              S: K 8 6
                              H: K 6 5 2    
                              D: Q 9 2     
                              C: K Q 3    
          The Bidding:  
                  South    West    North    East                  
                   1C      Pass     1D      Pass
                   1H      Pass     2S      Pass
                   2NT     Pass     4C      Pass
                   4D      Pass     6NT     Pass
                   Pass    Pass    
          Opening lead: 10S
     This hand caused a lot of bidding problems for the players
at the local duplicate game.  I have shown the auction that I
think is correct using standard bidding methods.  
     After the one club opening, North has a problem.  Any club
raise would be non-forcing so North has to find a forcing bid
that will not create a different problem.  One diamond is the
stand out choice.  Remember, when partner opens one of a suit he
is showing an opening hand but is only denying the values to open
a strong two bid.  This is a large range so partner has to allow
the opener to continue to describe the hand.
     South now bids one heart.  All this says is that he has four
hearts and probably not enough points to jump in the bidding -
let's say he has now limited his hand to a maximum of seventeen
points.
     North again has to make a forcing bid.  One spade would show
a four card spade suit and unless the partnership has a specific
agreement about this bid, may be considered as invitational but
not forcing.  Two spades should be considered to be "fourth suit
forcing" and does not promise a real spade suit.
     South's two no trump response says that he has nothing else
to say about his hand, so he probably has only an opener without
anything extra, but he does have a spade stopper, because North's
two spade bid does not promise any values in that suit.  It is
not unreasonable to place a diamond honor in his hand.  While it
is not uncommon to make a one no trump rebid with a suit unstopped,
two no trump is another story.
     We are at the key point in the auction.  Are there enough
tricks for slam?  South's opener shows two quick tricks as a 
minimum holding.  If the clubs come home, North can count 
nine tricks (seven clubs and two aces).  Add South's two tricks
and you get eleven - so the king of diamonds should give you 
a very reasonable chance for twelve.	
     North can bid Gerber to ask for aces.  Why is four clubs
Gerber?  Many players are now playing any four club bid after a
"first or last" no trump bid as Gerber.  In this case, the last
bid by South was a no trump bid, so four clubs is ace-asking.
     South bids four diamonds showing no aces.  North could now 
bid four no trump, six clubs or six no trump.  Five clubs is not
one of the choices.  This bid would guarantee all of the aces and
ask for kings.  There is a missing ace.
     It is difficult to count up to an opening hand for South 
without three kings and two queens, so six no trump is probably 
correct.  The last thing that you want to have happen is for 
the opening lead to be the ace of diamonds and then have a second 
diamond lead trumped by East.  After all, you have a seven card 
suit so why couldn't West?
     Here is the breakdown of the results for this hand.  One
pair played six no trump, making for plus 1440.  Four pairs
played six clubs for plus 1370.  Two pairs played three no trump
for plus 690, and two pairs played five clubs for plus 620.
     When you hold a very long suit opposite your partner's 
opening bid, look for a slam - more often than not you will be
right.  
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