Pointers on the Uppercut


Don't ask who has to have what for an uppercut to work, or who is likely to have what. You're asking the wrong questions if you do. You may be able to figure out who has to have what for an uppercut to work, but you can't locate 9's and 10's or even jacks by the bidding. On the Frank Stewart hand given, you'll note that the (double) uppercut works because his partner has the 9 (as well as the ace and another). There's no way you can have any assurance that your partner has a specific 9!
A better criterion is, "How useful will this trump be hanging onto it?" In other words, you'll want to uppercut when you're looking at cards that almost surely will be gobbled up on trump leads pretty soon. On the hand just alluded to, a defender had 8 6 4! Those cards aren't going to win any trump leads, so you might as well enter them into the game as nuisance cards, forcing out something from declarer while your partner doesn't have to play a trump.
Here is another case observed recently:
A 8 6
J 4 2 Q 5
K 10 9 7 3

This is the trump suit. Declarer ruffed a heart in dummy back with a diamond, ruffed another heart, cashed the ace of trump -- and now had trouble getting back to the closed hand. He tried a second round of diamonds, but West ruffed and led the high club, which both East and declarer were out of. Of course declarer could ruff it -- low if East lets it go by. But East can see that his queen's a goner as soon as declarer gets the lead, and so plays it even on his partner's high club.
You can see that this promotes his partner's jack, which was the setting trick on this slam hand. (Actually, they got still one more trick, so it wasn't the trick that did it, but it helped.) East had no knowledge that his partner had the jack, of course. If declarer had it, it would have been totally ineffectual, but on the other hand, not costly.
Be leery of the uppercut when you seem to hold the long trump. Oh, I suppose you could posit a situation where it would work. But by and large if you have the long trump, whatever your partner has that might be promoted will serve to draw some high cards from declarer, leaving you with some possibility of getting a trick through length.
8 5
J 4 10 6 3 2
A K Q 9 7

You've got a trump trick coming here. If you uppercut with the 10, you give declarer a free finesse for that valuable card, and now your partner's jack will fall, along with your little ones.
On the previous (spade) layout, declarer had no more entries to dummy, and so it would have been wrong for East to uppercut if he'd had a guard to the queen, for declarer couldn't have picked it up without East's help in that case.
Be cautious when there are some pretty key cards on your right:
A 10 6
J 4 2 Q 5
K 9 8 7 3

Here you've got a trump trick coming if you'll hang on a bit. The uppercut doesn't altogether promote the jack, when a higher card is to your partner's left. What declarer will do here is anyone's guess, but declarer would have the capability of picking up the trump suit without loss if East uppercuts with the Q.