A Twist of Sorts
J 8 5
A 7 2
9 8 6 3 2
3 2
4 3 Q 10 7
8 6 3 K Q 10 9 5 4
A 10 J 5 4
Q 10 8 7 6 5 K
A K 9 6 2
J
K Q 7 Contract: 4 spades
A J 9 4 Opening lead: 3 of hearts

Here's a twist of sorts on the principle of keeping the same number of cards in a suit as dummy holds (when convenient and practical). East can't keep the same number of diamonds as dummy holds. But there are two counterpunches to that. First, do your best, that is, of course, if you're not scrimping on another suit and your highest card beats the 9. Secondly, if you wanna keep the same number as dummy, why should anyone want to keep six hearts to dummy's three, or 5 to 2 after that opening lead (in response to East's heart bid)?
Oh yes,declarers have been known to lose control even in a trump contract, but that's pie in the sky when you can see declarer's getting a fairly even break. Further, a twice-guarded jack isn't too shabby a holding. Yes, of course when declarer has the top three cards in the suit, he can pick up that J as if it were a five. But it only takes two higher honors to go on one of the first two rounds for that J to be a third round winner, or at least in control of the third round. This might happen if declarer drops an honor from your partner, on say a queen doubleton, and it can happen if your partner can capture one of the top two honors with the ace or king. That holding is certainly worth hanging onto as opposed to a six-card side suit that declarer isn't going to lead for you.
Four spades is a miserable contract here. For starters, declarer always has to lose a spade, a diamond and a club. You might argued that declarer "could" take a double hook in spades and avoid a loser there, but no, he doesn't have the entries for that. Beyond that, there's the second round of diamonds when the A sits over the K Q low, and the third and fourth rounds of clubs. A miserable contract. But two defenders gave up the ghost and allowed declarer to make his contract by sluffing a low diamond, and each one was a firster, by which I mean, each one sluffed a diamond at his first opportunity to sluff! Yes, before even one of those long hearts! Like maybe hearts will go to the sixth round?
Here's one: opening lead a heart (East bid hearts in each case). Declarer wins, leads a club to the K and Ace, then loses a club to West, East sluffing the 4 of diamonds! It's really amazing that one would want to keep five hearts covering dummy's puny two hearts in this trump contract and have so little respect for a twice-guarded Jack. West continued hearts -- oh what a lovely suit to be holding in no trump. But it was a fleabite to declarer, who now played the K of diamonds to West's ace. West led a club now, ruffed in dummy, overruffed by East, a natural trump winner, giving declarer two more spades than East again, so another heart lead was another flea-bite. Declarer cashed the A K of trump, then the Q of diamonds, dropping the J and 10, and of course a low diamond to the 9 allowed declarer to take the rest of the tricks. Now we know what East is going to do with those long hearts he saved. He's going to throw them on diamonds -- declarer's diamonds.
The other declarer varied the sequence a little, so East didn't get around to sluffing the 4 of diamonds until trick 4! Declarer took the opening lead, led a club to the K and A, led the K of diamonds, taken by West, and now the Q of clubs by West brought the 4 of diamonds by East. The rest is pretty much the same. A club continuation, ruffed in dummy, overruffed by East, and that's the end of the defense. East even made it easy for declarer by leading the J of diamonds after the overruff.