North plays 6NT on the ♠2 lead. He wins in his hand and leads a spade to the king, then runs the ♥T to the jack and queen, unblocks the ♦AK, east discarding a heart, and leads a low club to the ten and queen. A club is returned to the ace.
The position is now this:
At this point, east should start paying attention. North now leads the ♠9 to the king, which promotes the ♠8, and west discards a diamond. Next comes the ♦Q discarding a club. If east discards the ♥8, a diamond is cashed and a heart can be run through west. If a spade is discarded, declarer cashes out 4 tricks very carefully, one in each suit. If east unguarded a club, the ♦J could be cashed, discarding a heart, and North's hand would become good.