A lucky 30-hcp slam. Switch the defensive hands, then presuming for the nonce that declarer relies on the Law of Restricted Choice when he finds the Q or J of clubs falling on his left, and you'd make just three no. But the cards are right for 6 no, and if that's your bid, you must play as if your bidding has been sound and you can make, which you can. But two declarers went down from a little too much fiddle-faddling around. When dummy comes down, you must think of establishing winners not immediately cashable, and not cashing the cashable unless you have a positive reason (such as shifting the lead from one hand to the other). Here, when dummy comes down, declarer will note certain plays he must make before he starts cashing out top winners: There is a double hook to take in spades. As it happens, both spade honors lie before the ace, so only one lead is necessary, but declarer doesn't know that and had better prepare for leading spades twice, since it won't always be so. [I.e., only one lead from dummy. A second lead is necessary, unless East ducks the J, but can be made from either hand.] Similarly with diamonds. The suit must be unblocked so that the top four cards can be cashed separately rather than spending two honors on one trick -- except that when the 10 falls doubleton, the presence of the 9 means you can overtake an honor on the third round of the suit. The heart finesse must be taken, and as for clubs, well, there are two ways of picking up three tricks in the suit: one is as the cards lie, and the other is to pick up a singleton honor on your left. Declarer must have all these situations in mind and not cash out until he's done all the housekeeping he must do!
Declarer went up on the opening lead, which is all right, even if the odds of dropping a stiff queen are slim. Now it would seem that the first step in a double finesse is in order. That's because you've gotta lead from that hand -- twice if the defensive honors are split -- whereas you can attack clubs from either hand, and the heart finesse must come from the other. East will doubtless cover the jack of spades, which you take, knowing that you can develop a second spade winner from either hand. But you don't want to knock out East's second honor now, since he'll continue the suit and now you're wide open with a heart hook to take. There'll be time enough for developing the second spade winner later. Now take your heart hook, which you've got to sooner or later. When that succeeds, try the K of clubs, finding the fall of the Q or J promising, continue the suit and find it is so, that you have three club winners. Now diamond honors, while you have an entry in hearts, in case the 10 of diamonds lies in the long holding. When the 10 falls doubleton, you know you can overtake your third honor and so can abandon the suit for the nonce. And now knock out East's second spade honor. Things are looking up. Do not cash the 10 of clubs. You don't need to yet. And it should be clear at this point that you need only knock out a spade honor to establish your second spade winner and 12th winner overall: Two spades, three hearts, four diamonds and three clubs.
To return to the first declarer: Winning the heart lead with the K, K of clubs, club to the A, run four diamonds, overtaking the third round jack to cash the 9, sluffing a spade. A spade! The second kicker to the ace is necessary for the double hook, unless second hand has both honors, as here, or a doubleton honor. But if declarer can still recover from that potentially expensive discard, he'd better hop to it while he still has an entry back to dummy by way of hearts. I'd feel a little queasy right now. Why cash out diamonds? As soon as the doubleton 10 falls, diamonds are cold and can be led from either hand. Declarer must get to establishing a 12th winner, which is to say taking the heart finesse and hitting them spades. Not a good idea running diamonds, sluffing a spade, though this alone didn't kill the contract. Now a club to the 10, a heart to the 10, ace of hearts (!). Ten of spades covered at trick 11. You might note that before starting his double hook in spades, declarer had wiped out entries in hearts and diamonds as well as stoppers in hearts and clubs! The spade hook should have been taken while he still had stoppers in all suits (and entries were abundant). But wait a minute. He doesn't have to lose a spade to his LHO to establish two spade winners. The cards were so friendly that even after trick 11, he could still have made the hand by simply playing the 9 of spades to his RHO's K, whereupon that defender would have had to lead a spade to the J. East couldn't save a winner outside the spade suit! But instead of a spade to East's K, declarer tried the 7 of clubs, now losing that trick and one to the Q of hearts.
As so often happens, declarer's early plays didn't queer the contract, but being pointless, foreshadowed a declarer that didn't have his eye on the ball.
The second declarer also went up on a heart lead and now cashed the diamond honors in the closed hand, took the heart finesse, cashed the A of diamonds, sluffing a spade also (this is where I'd get uncomfortable if watching this as dummy), cashed the top two clubs, ending in dummy, led the J of spades at trick 9, two tricks earlier than his counterpart above, captured the K and led a heart to the king! ! ! Now that's beyond the pale. Why the king of hearts, his last stopper in the suit and his last entry to a second spade winner, if he'll simply knock out the Q of spades? Now came a club to the 10, and tricks 12 & 13 were identical to the above declarer's. This declarer also tried to win his 12th trick with the 7 of clubs even though he too was looking at powerful spades that would have garnered a 12th trick by simply knocking out East's second honor. He too had wiped out his heart and club stoppers before knocking out the spade honor he must for his second spade trick and he too had the luck that the defender with the last spade stopper couldn't lead a heart or club, but he too went for an unproven 7 of clubs instead of a second spade winner by simply leading the 9 to the K or Q.