How Do Porcupines Make Love?

Very Carefully

Q 8 7
A Q J 9
Q 9 7 2
A 7
K 10 9 3 2
K 6 4 2 7 3
K J 5 9 6 4 3
K 4 3 10 9 8 6 5
A J 6 5 4
10 8 5
A 10 Contract: 4 spades, 6 spades
Q J 2 Opening lead: various

How do you make 6 spades here? Very carefully, that's how. You've got three finesses to take and a ruff in dummy to maneuver before all trump are out. One of the finesses is off, but by chance, it's in a holding where you'd almost certainly have a loser even if the K were onsides. When you're missing K 10 9 on an eight-card holding, even an onsides K will probably still lead to the loss of a trick in that suit. (A doubleton K with East could be picked up, and by the magic of the spots, a K guarded by the 3 2, leaving West with 10 9, could be picked up, as West's spots are smothered.)
So . . . you'd better take the other finesses, and the club in particular very early, since you'll wanna ruff the third round of clubs. We can see that it doesn't matter whether West covers or not.
What went wrong? Well, for a declarer in four spades, going up on the 6 of hearts opening lead was a good start for a bad board. That disinclination to take a natural finesse (presumably because led by a defender) cost this declarer two tricks. She had to lose to the K of hearts others don't hafta lose to, but when West was in with the K of spades on the first round of trump, she was able to cash the K of hearts and give her partner a ruff!
Since that was 3 tricks declarer had already lost, she would hafta play the rest of the hand very carefully, which is to say that since a diamond loser has to go on the heart differential, a club must be ruffed. East (after ruffing the third round of hearts) returned a diamond, taken by declarer with the ace. Now the A of spades, spade to the Q (so much for a club ruff), sluff a diamond on the fourth round of hearts, come to the closed hand with the ruff of a diamond, take the club hook, and now there's no way to avoid a club loser.
Ya know, in going over this hand, I had a brief glimpse of what just might have been a squeeze, which I hadn't noted before. West is guarding the third round of diamonds and West has to cover a club honor. However, I saw on further reflection that West is only pseudo-squeezed. The hand would reach this four-card end position, with the lead in dummy:

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Q 9
A 7
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K J 9
K 4 10 9 8
6
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Q J 2

Where it is evident that not only must West keep a guard to his K of diamonds -- correction: must keep a guard to each K -- getting down to only two clubs, but East has a role to play in keeping three clubs and not getting lazy, thinking it doesn't matter what he throws on heart & spade leads. If both defenders are alert, West would have the K of diamonds after a diamond ruff here, would cover an honor if led, leaving his partner the task of covering the third round of clubs. [Actually, on the following day, I found West squeezed in diamonds and heart. See below.]
Lemme look at a few in slam: Opening lead a club, riding around to the J. Heart 10 holding, low spade from the closed hand. [Since, with the 9 of hearts in dummy, declarer could overtake the 10 without loss and finesse, that's a little curious. However, since declarer is very likely to lose a spade, anyway, as discussed above, this doesn't strike me as a terribly egregious disinclination to finesse -- such as deciding against the heart finesse above. Just a strange one.]
West went up on the low spade and led a heart, taken by the J, cash the Q, then A of spades, run hearts, sluffing a club, and now came a "finesse" of the 10 of diamonds into the J for the setting trick. Declarer, of course, is looking at a diamond loser, barring a totally improbable stiff K -- or maybe a stiff J with West smothered? -- and had no chance at the point. Could declarer have made it?
Well, let's go through it. First we note that getting a ruff in dummy is far likelier to be successful than dropping a stiff K. From there, we go to the A of clubs at trick two and run the Q. Why not low to the J? We're going to need the three top honors for drawing trump, and we're going to have a bit more communication starting with the Q, allowing us to ruff with a low spot and perhaps continue to the A J. Further, we're going to want entries to the closed hand a lot more than we'll need entries to dummy.
Now West could play a cagey game of his own, ducking the Q of spades. We're feeling confident that things are working out, continue with a lead tot the J, whereupon West pounces and continues the suit. And so it goes.
But defenders aren't so likely to be cagey. And besides, we could play a cagey game right back and go up with the A second round, letting the K of trump go hang. But we'll say the finesse loses to West's K is followed by . . .
No, it looks to me as though slam cannot be made. Declarer has a theoretical 12 tricks, but it looks to me as though he won't have enough entries to the closed hand to ruff a club and lead hearts three times, even granting that he gets two hearts leads outta that 10. The hand would look like this:

8 7
A Q J
Q 9 7 2
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10 9 3
K 6 4 7
K J 5 9 6 4 3
K 10 9 5
A J 6 5
8 5
A 10
J

Declarer could handle any lead but a spade: he'd ruff a club lead, come to the A of spades and finish drawing trump, take a heart finesse, come back to the A of diamond and take another heart finesse, then sluffing a diamond. A diamond lead would obviously make things easy for declarer. Heart lead? Win on a finesse, come to the A of spades, ruff a club, back on the ace of diamonds, draw trump, another heart finesse, then sluff a diamond on the fourth heart. But a trump return? Declarer would win in the closed hand, ruff a club, come to the A of diamonds, draw the last trump .... whoops! Declarer could make by leading all trump. West would be squeezed at, um-mmm, trick 10 when declarer leads his last trump from this position:

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A Q J
Q
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K 6 4 ------
K 9 6
------ 10 9
5
8
10
J

Where it is evident that if West sluffs his K of diamonds, declarer sluffs a heart and makes on a heart finesse, and if West sluffs a heart, declarer sluffs his Q of diamonds and can now establish the suit on one more finesse.
The funny thing is that I didn't see that until I tried to establish how a trump lead would do declarer in -- after I'd envisioned another winning line. For that, I hafta go all the way back to trick 2.
West opened with a low club, riding to the J. Why would I waste a valuable entry leading toward a now stiff ace. I can play that card from dummy. Hence, at trick two, let's take a heart finesse on low to the Q or J. The reason for that will become apparent soon, if it isn't already. Now we cash the A of clubs and finesse the Q of spades into the K. The hand would look like this:

8 7
A Q 9
Q 9 7 2
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10 9 3
K 6 4 7
K J 5 9 6 4 3
K 10 9 6 5
A J 6 5
10 8
A 10
J

Where declarer can obviously handle any lead. A trump? No problem. Let it ride to the J, ruff a club, back with the ace of diamonds, finish drawing trump, and now declarer can make use of the fact that you can get two heart leads outta that 10. How about a heart lead? No problem there: let it ride to the 10, ruff the club, back on a trump lead, and when all trump have been drawn, declarer can take a third finesse in hearts, dropping the K fourth round as he also drops his diamond loser.
I'd be lying if I said this was a piece of cake that I'd have tossed off without a sweat. I didn't see these lines after a day of looking at 52 cards (well, not the whole day). This was originally put under "What Went Wrong", but that category is devoted to fairly simple hands butchered with fairly elementary mistakes. Which seemed inappropriate for this hand. So I thought it best to slide it over to "Interesting Hands". For even if the winning (slam) line is tough to find, I always hold that even the most recondite lines offer a little stretching of the imagination, even if it takes a while to find it.
We can't use the value of the 10 of hearts to take two finesses before trump are out or West could give his partner a ruff. On the other hand, we can't afford to let hearts go hang until late in the hand for we won't have the entries we need for all those finesses. [Well, so I thought before the squeeze popped up.] So the solution is to take one finesse while reserving the 10 for its particular usefulness until later.