I might add a little to what I previously said They set the contract 2 tricks on their defense but, matchpoints or not, I would be concentrating on setting it 1 if possible. Generally this is a good idea, but very much so on this hand. Some pairs might be in 4S their way, some pairs might be in 5DX our way, so if the hand can be held to 10 tricks in spades the one thing I really don't want is for them to make 11 tricks when where is the third defensive trick? Forget the fourth, where is the third? Might partner have a stiff heart? It would mean that the opponents have an 8 card
fit but we seem to have a lot of
so that's not impossible. If partner has a
trick coming he will probably get it. So I think a
is not crazy. Maybe I would, maybe I wouldn't, but not crazy.
So suppose I lead the
9. It goes 9-T-Q-A, I suppose. Of course declarer might put up the A at T1 but then the fall of the Q would clearly be stiff, and if declarer had played small from the board then also the Q would be a stiff since the 9 was already going to force declarer's A so why play the Q?
Ok, 9-T-Q-A, back to the board with a
, perhaps the Q to the A, but the K is still known to be with declarer, and then a spade, probably the J, losing to the A.
Now what? What I would not do is lead the
8. If this is not ruffed then all three
on the board are good and even if declarer started with 5=2=3=3 shape he is making 6. He wins the
on the board, picks up the
, goes back to the board and tosses all of his
. The
4 would be a little better, declarer will surely hop up, and now, while in theory he has enough pitches the transportation gets a little tough so if he started with the 5=2=3=3 shape we probably still hold him to 11 tricks. But why risk it? Surely I just cash the top
and lead another
. As the cards lie, we set 1 trick. If the
is not ruffed, he makes it.
So, matchpoints or not, I am not going after a 2 trick set. As to some message via the trump suit, say on the
lead E plays the 8, it could be from Q8. Or Q98. Even if we were playing some system, I would not be confident of what is being said, not so confident as to let it alter my play. When in with the
A I cash the
A and lead the
4. It gets ruffed or it doesn't. The we go on to the next hand.
Added: Pairs have, as Sanya mentioned, developed various carding agreements including with the trump suit. One that goes way back, at least to Goren, is that when declarer plays on trumps and you hope that partner can get in, playing spots high then low says that you started with three trump and that you are able to ruff something. So, in this case, playing the 8 from Q86 would be an attempt to convince partner that you can ruff something. Usually, as here, he will have no trouble figuring out what it is. This has nothing to do with udca, it simply applies to the trump suit regardless of other carding agreements. This meaning was once very standard, and I think it is still the default meaning.