gnasher, on Apr 29 2008, 01:18 PM, said:
I think that the people who played clubs from the top were wrong twice over. If I were forced to play three round of clubs before guessing diamonds, I'd finesse against East rather than playing for 3-3, even though 3-3 is more likely than 2=4.
From the point that you have cashed two top clubs and played a third one, without seeing the jack:
- If you play for a 3-3 break (which is moderately odds-on) and then succeed, presumably you will then play West for ♦Q, because he will be known to have four diamonds to East's three. The probability of success will therefore be
4/7 x (a bit more than 50%).
- If you finesse against East (which is moderately odds-against) and then then succeed, you will be able to claim on a squeeze against West, who will be known to be 5=1=5=2. The probability of success will therefore be
1 x (a bit less than 50%)
This completely ignores the possibility of Jx of clubs!!
I figured that clubs gives us a better chance of picking up the suit than diamonds and I will save my guesswork for the end. Do I need to prove that picking up clubs is easier than diamonds? Maybe you're morally certain where the diamond Q is, then fine? Can't prove you wrong there.
But it's ultimately a comparison of:
Odds of guessing clubs * odds of guessing diamonds given we've guessed clubs
vs.
Odds of guessing diamonds * odds of guessing clubs given we've guessed diamonds
I grant you that the latter conditional probability is much higher than the former. However, it's also the case that the odds of guessing clubs is greater than the odds of guessing diamonds.
So just before I put my foot entirely in my mouth, did you mean to first play two rounds of clubs and then guess diamonds? Or were you completely ignoring the fact that
♣Jx might fall?