This is one of those by no means infrequent hands that allow themselves to a simple count for the contract, but which declarers, commonly calling themselves advanced, often manage to butcher. Let's count. The opening lead hardly matters since all suits are solidly stopped. You have (starting with absolutes) three spade winners, three heart winners, three diamond winners, and two club winners, counting the certainty of developing a winner with the Q J regardless of where the king lies. Just need one more, huh? Of course, you may be able to run hearts for five winners. You may get a 12th winner by losing a spade and cashing the 5th round. But wait a minute. There are dangers.
You don't want to test hearts because if they don't split 3-3, then you've uncovered a heart winner. You don't want to figure on a fourth spade winner, since you've got to lose a spade, and so can't afford a losing club hook. So the first order of business must be to take the club hook. Leading toward the jack. You want to lead toward the jack because if you catch a K doubleton on your left, you can pick up the whole suit for 13 tricks. If East takes the jack, you can now hardly go wrong.
You test clubs for a 3-3 split, and getting it, need look no further. If you don't get a 3-3 split, you still have the possibility of 3-3 hearts and of the J of diamonds falling. But you must be looking for that 12th trick before uncovering winners for the defense! When you get it, then you cash out.
Here's what this declarer did: He took the opening lead and continued hearts. Now what can he do? A finesse into the king of clubs settled his hash. Of course, he had a means of making his contract even then: first he has to cash three spades and lose a spade, then decline the club hook if that is West's lead, then come to the king of diamonds, cash the fifth spade (sluffing hearts and clubs) and take the diamond hook. But that's too esoteric. Compare that with simply saying, I've got to develop a 12th winner before cashing out top cards. The hearts will wait if they are 3-3. Oh, yes, if they're 3-3, and the J of diamonds falls, he's got an overtrick, while I'm losing a trick to the K of clubs. Oh, please. Overtricks are lovely and should be sought out when your contract is secure. But your first task is to do what you can to secure your contract!