dburn, on 2011-March-08, 20:49, said:
What is the substantive difference between Law 69B and Law 71?
The claim laws provide 3 different standards for judging claims/concessions, at 69, 70 and 71, each applicable in different circumstances, according to who disagrees with the claim and when. I'm sure you understand the difference between when to apply which standard. What you are asking is what is the difference between the standards in each case. (Well you don't ask about Law 70, but I put it in for completeness.)
Law 70 is the usual one we apply when there is an immediate objection to a claim. The benefit of the doubt lies with the opponents of the claimaint, and the standard is close to overwhelming (any normal play).
Law 71 is when a claimant who concedes a trick tries later to change his mind. The benefit of the doubt lies with the opponents of the claimaint, and the standard again is close to overwhelming (any normal play).
Law 69B is when a the opponents of a claimant, who originally agreed the claim, later change their mind. Now the benefit of the doubt lies with the claimant, however the standard is not overwhelming, (no mention of normal plays, it is merely "likely").
So that is the substantive difference - the benefit of the doubt now lies with the other side, but unlike the law 71 criterion, it is not the overwhelming criterion of "any normal play", merely a "likely" standard. For avoidance of doubt:
Quote
The Director shall not accept from claimer any unstated line of play the success of which depends upon finding one opponent rather than the other with a particular card [here, the jack of spades]". Should the Director take this into account when making his ruling?
"
No, this is not the standard that applies here, the standard is the one stated in Law 69B, of "likely".
We don't judge claims under Law 69B very often, so we are unfamiliar with its contours. I think the case you bring up is a good one for exploring its contours.
Also the question you ask is a good one. Does "likely" mean "anything more than 50%" or does it require somewhat better odds than that? I think we don't know.
I think one could argue this particular case both ways.
(1) For the claimant. To go off, W has to ruff high and then finesse, two decisions that might go either way. One could therefore argue that ex ante it is rather less than 50% it will go off, because each decision has to be in NS's favour for it to go off. That's probably not good enough to be "likely" that NS will get a trick.
(2) For the claimant's opps. At the moment of the claim, West thinks he has all the tricks, so it is reasonable to assume he will ruff high at that point. Then when he comes to think about drawing trumps, he will realise the error of his ways. Because of the 4-2 heart break, it now becomes slightly favoured to play for the finesse. It is likely that a player will choose a line of play that is slightly favoured. We don't play 40% lines 40% of the time when we have a 60% alternative, we play the 60% line whenever we realise it is better than the 40% line. Now in this case a calculator tells me it is 53:47 in favour of the finesse, but nonetheless reasonably competent bridge players ought to take it most of the time, as we should realise that the odds are in favour of the finesse even if we can't calculate them precisely at the table. So it is likely that he would go off.
Take your pick, I think they are both reasonable rulings. I'd probably choose (2).