South opened One Spade and West joined in, dangerously, with Two Clubs.
Playing negative doubles, North decided to pass and wait for a reopening double from his partner. However, South chose to bid Three Hearts instead. In rage, North jumped to Six Hearts, and all passed.
West led a top club against the slam and, although a trump switch was marked and would have defeated the contract, he switched to #2, hoping to mislead South about the distribution in this suit.
Declarer won with #K in dummy. Having escaped the trump switch, his plan was to make three side-suit winners and nine trumps by cross-ruffing. He cashed #A and ruffed a club in hand. The ace of spades was followed by a spade ruff in dummy. Another club was led and East discarded a spade with a view to over-ruffing dummy later in the play.
This forced declarer to change his plan. He ruffed another spade low in dummy and, when both the spade king and queen fell, he was able to draw trumps and enjoy his long spades.
Preserving his spades would not have helped East. Two spades would then be ruffed low with !5 and !8, while !Q remains in dummy to take care of declarer's last spade.
East-West game; dealer South
!Q 8 5 4
#A K 7 3
2Q 10 8 6 4
4K 10 2 4Q 9 7 5
!J 7 2 !9
#Q 2 #J 10 9 8 5 4
2A K J 9 2 25 3
4A J 8 6 4 3
!A K 10 6 3