[kfay]

Came to a stalemate with karlson on this one until he ran a sim. I'm still not convinced.

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LHO leads the ♠J, RHO follows with the 6 and you win the ACE.

You lead a low ♦, LHO pitches the ♠2.

Line A) You Play RHO to be 3253:
T3: ♥A
T4: ♠K (pitch a club)
T5: ♠ruff
T6-7: ♣AK
T8: ♥K
T9: ♣ruff
T10: ♥Q from:

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Line B ) You play RHO to be 2353 or 3352
T3-4: ♣AK
T5-7: ♥Q, K, A
T8: ♠K (RHO drops the Q, LHO does or doesn't drop the 10)
T9: ?

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What do you ruff in dummy? Opponents play optimally.


What's better, Line A or Line B? What's the best play at the diagrammed position in line B?

[Cascade]

Heart doubleton is more likely.

A club doubleton is more likely than a spade doubleton.

[ceeb]

I agree with Cascade as regards dealing probabilities. Given the trump break,
3253 is over 14%
2353 is under 10%
3352 is under 12%.

However, there is a restricted choice argument that in the last case LHO might well discard a club from 5305, whereas in the first case with 5404 the defender has little choice because of the excellent bidding. So if I chose line 2 I'd tend to ruff a club.

[cherdano]

Any computation that ignores inferences from the lead is not enough.

[gnasher]

Line B is definitely wrong, because of Line C:

Play as in line B, but win the third heart in the North hand.
If East is 2452, ruff the last heart, cash DA, and ruff a black card with the 6.
If hearts are 3-3, lead the last heart, which LHO has to ruff. Overuff with the ace and guess what to ruff in hand.

[kenrexford]

cherdano, on 2011-January-25, 10:31, said:

Any computation that ignores inferences from the lead is not enough.

Not to mention that any computation ignoring the bidding. I mean, 6♦-P-P-P was clearly not the sequence. If RHO has has only two spades, then LHO started with six of them and might have overcalled in any number of scenarios, especially with a void in trumps (and thus 6-4-3-0 shape). So, a REAL auction makes 3-card spades to the right probably a fair bet.