A flexible bid
The late Eddie Kantar, one of the great writers and teachers in the game’s history (and a world-champion player) told this story. Eddie was delivering a lecture to a group of intermediate and advanced players. He began with this statement: “Not all 4NT bids are Blackwood.” Whereupon the intermediate half of the class got up and left.
A bid of 4NT is too handy to restrict its use to ace-asking. In today’s deal, North’s 4NT asked South to pick a trump suit. North could have doubled, giving his partner the option of playing for penalty, but North’s hand suggested that his side should declare. (East in fact would have wrapped up 10 tricks at four spades doubled.)
As it happened, North found his partner with diamond length. Against five diamonds, West led the king of spades, and South ruffed in dummy and led the jack of trumps, overtaking with his queen. He ruffed his last spade in dummy and led the king of trumps. East took the ace and shifted to his seven of clubs. South won with dummy’s king and led the ace.
He intended to ruff the third club, draw the missing trump and make an overtrick by setting up a long club in dummy. When East unkindly ruffed the ace of clubs and led another spade, South ruffed but eventually lost a heart to East’s queen for down one.
South could have made North’s 4NT look good. After South took the king of clubs, he does best to lead a low club from dummy. Later he can ruff a club to reach his hand, draw the missing trump and discard a heart on the ace of clubs.