West may have the jack of spades, but there's time for that later. Your best immediate shot is to find West with the Qxx. To take advantage of this possibility, South must lead diamonds twice.

Win the second club with the king and lead a diamond. North wins and returns a heart to South's queen. Now a second diamond catches West.

It would be a mistake to drop the king of clubs at Trick One, as many players would do. Not only do you need the quick entry for diamond leads, but pitching the king allows East to reel off four quick club tricks, on which West gets his life-saving diamond pitch.