Re Phil's analysis the postscript about considering the opening bid seems relevant. 60% for the combined chance of dropping a major suit queen seems about right, but the probability of winning a
♠Q finesse through the opening bidder is similar and there are additional indications from trick 1: leading
♣4 from
♣9x(x)4 may counterindicate outside honors; RHO ducking trick one is less likely with both
♦AK and hence suggests
♠Q more strongly.
But rather than the technical chance via cashing aces and kings I like Nigel's play: Collect 52% equity by cashing top trumps, then instead of simply spade drop try for an endplay via (1)
♠Q with RHO, (2) defenders fail to cash RHO's
♦ top(s), (3) we read the distribution.
But what is the
♠ finesse line really worth? If you would choose it, surely exploring in
♦ per dake is nearly cost-free.
MrAce, on 2011-January-07, 17:24, said:
If u play
♦ to dummy, North plays low, South takes 9 with T, cashes
♦ A and plays another
♦. I hope that helps
It helps a lot -- the very weak indication from trick 1 play that RHO hasn't got
♦AK,
♣A has turned into a strong appearance that RHO had
♦A10x. (Are these birds clever enough to defend this way when RHO holds
♦AK10x
♣AJ108x rather than trying the
♣A instead of the small
♦? By the way why not
♣A in any case? What does RHO know from the opening lead?) Therefore the opening bid seems to place the
♠Q onside.
Of course it was a little lucky to get such telling information from the diamond suit. There are imponderables but it's maybe a 1/3 chance that LHO has a diamond top and a 1/4 chance that we learn about it. Assuming you take 60% via cashing tricks when the
♦ plays aren't informative and nearly 100% by
♠ finesse the 1/4 of the time like the actual hand, the net is 60%(3/4) + 1/4 = 85%. If you believe that estimate it's hard to beat.