This deal was played by Jeff Meckstroth, many-time world champion, when he was just starting out. Meckstroth had to overcome an excellent defensive play to bring home a slam.
West led the ♥K, taken in dummy with the ace. Meckstroth drew trumps in three rounds, played a club to dummy’s ace and led a low club toward his jack. East won the ♣Q and made the excellent shift to the ♠K (a Merrimac coup: sacrificing an honor to remove an entry, usually from dummy.)
Note that any other play would have made it easy for Meckstroth. A club return would have allowed Meckstroth to win the jack then enter dummy with the ♠A to take two spade discards on the high clubs. A low spade would have allowed Meckstroth to win the ♠Q, unblock the ♣J and enter dummy with the ♠A for one more discard on a high club.
The ♠K removed dummy’s entry while the club suit was still blocked.
Meckstroth was not done, however. He ruffed a heart to the closed hand and cashed two more trumps. This was the position:
Meckstroth played the ♦9, discarding dummy’s ♥10. East was forced to surrender trick 12 to declarer by unguarding one of the black suits.
The full deal: