[manudude03]

On a tablet while my computer is out for repairs so I hope this comes across okay. You are playing in a trump suit with this combination:

KJ98
Vs
A742

and the defense made you ruff twice in hand so you now have A7 in hand and have to play this suit without loss. You cash the ace and it goes A-3-8-T. When you lead to the next trick, LHO follows with the 5, assuming the suit is 3-2, do you drop or finesse? The book says finesse, but how much weight do you put into people not randomising enough with small cards or the fairly well known falsecard from QT?

[cherdano]

Difficult to say without seeing the whole hand and knowing the quality of the opposition. T from T6 is a difficult falsecard, in the sense that defender has to be fully awake and be 100% sure that you don't have to take a ruff in dummy in a suit where you could overruff. But it's not so difficult for a defender who is always paying attention and always knows what you are about to do whenever they should know.

I think the more interesting inference is from the fact that they forced you to ruff twice - LHO might not be willing to do that with Qxx since it would make it very awkward for you to misguess the Q if you had ATxx.

[manudude03]

I was fearing that may be the answer. The inspiration comes from a hand in the last camrose trials so competent players. I don't have the records now, but the hand was something like this. Sorry for no hand viewer.

KJ98
Txx
Atxx
Jx

Vs

A742
x
Qxx
KQTxx

The auction starting with south was 1c-p-1d-1h-1s-2h-3s-p-4s-ap. LHO led the ace of hearts RHO dropping the queen. LHO then switched to an uninformative diamond. This was run around and RHO wins with the king before leading the king of hearts which you ruff. You then start playing on clubs and RHO wins the second round and then leads the jack of hearts which you ruff again. Now you just need to bring trumps in and as the OP says LHO contributes the 3 and 5 while RHO contributed the ten.

[FelicityR]

I believe you have already answered this in the header: Potential falsecards. Except if you have inferences from the bidding that indicate a drop as opposed to a finesse, or you are looking for a top at pairs by going against the odds, I'd always play 'by the book'.

When I played regularly at the club there was one player who regularly falsecarded, and in the end other players got wise to his manoeuvring and totally ignored his shenanigans.

[Winstonm]

Your question enters into the ephemeral realm of table feel. Playing behind screens, the whole idea behind restricted choice is to assume there is no choice; however, with Q10, looking at KJ98 in dummy, there is the choice of playing the Queen to tempt declarer into finessing the 9, playing for a 4-1 break.

If north held KJ53 this problem would have been easier.

[MrAce]

Arend (Cherdano) nailed it imo.

[FrancesHinden]

It's not just a matter of 10x and Q10 doubleton, you can also make if trumps are 4-1. You are here having cashed the ace of spades:

KJ9
-
A10x
-

7
-
Qx
KQ10

if LHO is down to Qxx spades and at least one diamond and one club (or no clubs and the DJ is falling) you can play spade to the 9, diamond to the Queen, master club and watch him squirm.

[steve2005]

The odds favour finessing unless you have received other information on the distribution of the hand. Peeking would help lol.

The playing of the small cards if true cards imo don't make not finessing greater than 50%. And the cards opps have can virtually be played in any order without hurting the number of tricks they get.

[manudude03]

I suspect one or two posters here are missing the point of the question. I even said in the OP that the book says to finesse. Of the ten ways the suit can break 3-2 (3 on the left), 6 contain Qxx and 4 are xxx. However, once you see 3 spot cards played, there is only 1 of each possible. At the time you have to guess, assuming it is 3-2, then it can only be 653/QT or Q53/T6. Without any other information, these are equally likely. However, the latter is considered more likely as it means RHO had a choice of 2 cards to hide while on the first LHO has a choice of 3 cards to keep hidden. That's all theory.

However, I am talking about what happens in practice, not in theory. If the layout was 653/QT, how often is LHO holding onto the 6 in practice? Similarly, if it is Q53/T6, how often is RHO holding onto the 6 in practice? If the answer to the latter was lower than the former, then would that not suggest playing for the drop? As Winstonm said, it is table feel.

For what it's worth, on the hand in question, it was Q53 onside. Declarer, possibly influenced by feeling 30+ imps down with a few boards to go (opps bid a thin slam which made and his side has had a disaster where they took +300 when 7NT vulnerable makes without much difficulty), played for the drop. I had considered the possibility of a trump coup like on Frances' line, but the defense knows how trumps are breaking and you likely would have had a heart played at trick 2 planning on forcing out the hand, which would make Qxxx close to impossible to pick up.

[dokoko]

Seems most of you missed an important point (or forgot to mention it).

- If you need a 3-2 break and the 10 is an honest card, the Q has to be with East and you should play for the drop.
- If you survive a 4-1 break and there is even a small chance of a false card, finessing is clear.

So you should first decide whether you need a 3-2 break or not.

One additional note: There is even a "restricted choice" aspect in the situation. If RHO can read you for your actual trump position, he might play the queen from QT.