Down to the last two rounds in rubber bridge. Declarer claims remaining tricks only to discover that he has miscounted. He claims the two tricks with Q-10; however, opponent holds the J and depending on how he plays the cards could lose one trick. How is this handled? Is scoring affected?
Consider the same scenario only opponent holds the Q. Do opponents just get the one trick and game is scored as usual?
Laying down your cards doesn't automatically end the hand: either opponent can ask to play it out, with you playing as you said you would. So if an opponent has the Q of trumps, he will take it on the first trick, and then choose what to lead knowing what is in your hand; if that gives him an extra trick, so be it. You can't be expected to play irrationally; so if the lead is in your hand, and you say 'Play trumps', it would be expected that you play the Q before the 10. On the other hand, if the lead is in dummy, and you play towards the Q10 without specifying which, the opponents can ask you to play either. This is because, having seen all the cards, you can't choose whether or not to take a finesse.
The laws of Contract bridge try to achieve a result equitable to both sides (and not to punish), but in case of doubt, resolution might favour the non-offending side.
Laws 68-71 deal with claims (and there are alternative versions for the Club setting), and you can read about them here: http://web2.acbl.org/laws/rlaws/lawofcontractbridgecombined_2004.pdf (2008 version).
Quoting a paragraph from Law 69 (non Club, 2004 version):
The objective of subsequent play is to achieve a result as equitable as possible to both sides, but any doubtful point must be resolved in favor of the defenders. Declarer may not make any play inconsistent with the statement he may have made at the time of his claim or concession. If he failed to make any appropriate statement at that time, his choice of plays is restricted thereby:
[snipped]
I believe there is also a provision which allows declarer to follow a routine/rational line of play which does not contradict the plays specifically disallowed, in case the claim is rejected. Of course, there are quite a few subjective words in the laws which might lead to different resolutions by different directors.
Perhaps in your case, it would probably be irrational for declarer to play the 10 instead of Q and dropping the J.
Disclaimer (pun intended): I am not qualified to be a director, so what is written here is just my interpretation. (Though I did get a chance to talk to some directors about this in the past few years of playing and what I write here is influenced by those discussions)
