[antonylee]

You have AT2 opposite Q973 in dummy, which has two outside entries; you need three tricks (imps). I think the best line is to take the intrafinesse (small to the nine, then small to the ten if the jack won or cash the ace if the king won). Suitplay agrees with me but gives that line barely more than a 50% chance of bringing in three tricks. When I looked at the details, it is true that many bad splits doom you as well, but in particular Suitplay only gives two tricks for the intrafinesse line when the suit splits J654=K8, when in fact you have three (small to nine and king, use one entry, small to king and ace, run the ten and use the second entry to cash the seven, while Suitplay overtakes the ten with the queen on the third round).
Is that a bug, or did I miss something?
As a matter of fact the actual probablilities matter because Suitplay claims that ace and small to the nine is less than 2% behind for three tricks, and will bring four around 1% of the time (when the singleton king falls). I actually needed yet another trick to bring in my contract, either through a 3-3 split or a double squeeze, so perhaps it is indeed worth playing the ace directly as that little chance for four tricks may be worth taking.

[wank]

what you missed is that the opp with kj8 should win the king. kj8 is more likely, a priori, than k8 so that's what it plays for on the 3rd round.

obviously the chances of the opp finding the play are rather variable.



Quick whine: recently i had q10 stiff under j9xxx with declarer marked with 3 on the bidding. He cashed the ace swiftly, so i decided ak8 was much more likely than a8x otherwise he'd at least think about the intra-finesse. i perforce dropped the queen to give him a finesse if he had ak8. lo and behold, that's what he did have. he crossed to dummy played towards the k8 and rose dropping the 10. I resolved to hold my cards up.

[gnasher]

antonylee, on 2012-November-20, 03:27, said:

You have AT2 opposite Q973 in dummy, which has two outside entries; you need three tricks (imps). I think the best line is to take the intrafinesse (small to the nine, then small to the ten if the jack won or cash the ace if the king won).

That's not an intrafinesse, it's just a finesse against the jack followed by a finesse against the king.

The defining property of an intrafinesse is that the second finesse pins the honour that was finessed on the first round. The intrafinesse equivalent to your example would be A97x opposite Q8x, playing low to the 8 and then running the queen.

[phil_20686]

Suitplay is always right. Except when it has a memory overload error.

[antonylee]

Thanks for all the comments, that was illuminating.

[TimG]

Is this position already covered in the "mandatory falsecard" thread?