[kayin801]

First one is a sanity check, making sure I'm only 99% crazy and not 100%:

Scoring: IMP

1♣-2♠-X-P-
3♠-P-3NT-AP
Lead is ♠2 in 3NT in the South

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1♣ was variable, showing either any balanced hand or a strong hand with one/both minors. RHO has a necessity to overcall this bid, so it's not 100% assured that he has all remaining 9 points. Now the opponents are heckling you for thinking when a 21 pt dummy has come up. In a higher level contract you would test clubs for lack of tricks, but is there a better line in 3NT than the double diamond finesse or a better way to combine chances? Spades are 6-3 with no blockage.



Second hand, you're South again.:

Scoring: IMP

P-P-1♣-P
1NT-P-2♣-P
2♠-P-3NT-AP

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Wrongsided! 1♣ was a strong club, 1NT showed heart length, 2♣ was a relay, 2♠ showed spade shortness. What are you leading if a) the spade shortness promises a singleton or void, or b ) if RHO could have up to two cards in the suit?

[quiddity]

Maybe a better line on the first one is to cash AK of diamonds hoping that either the Q or T will fall. If that fails, cash hearts ending in dummy and try to guess clubs.

The chance of this succeeding is something like:
P(singleton T/Q) + P(double T/Q) + P(QTx) + P(club guess)
15*(2/6) + 48*(5/9) + 36*(1/4) + 50
5 + 26.6 + 9 + 50 = 90.6

[eyhung]

quiddity, on Jan 14 2010, 11:43 AM, said:

Maybe a better line on the first one is to cash AK of diamonds hoping that either the Q or T will fall.  If that fails, cash hearts ending in dummy and try to guess clubs. 

The chance of this succeeding is something like:
P(singleton T/Q) + P(double T/Q) + P(QTx) + P(club guess)
15*(2/6) + 48*(5/9) + 36*(1/4) + 50
5 + 26.6 + 9 + 50 = 90.6

I don't agree with your numbers.

P (singleton T or Q) = 2 cases out of 6 (6C1) = 1/3 * 15 = 5
P (doubleton T or Q) = 9 cases out of 15 (6C2) = 3/5 * 48 = 28.8
P (QTx) = [EDIT: 8] cases out of 20 (6C3) = 2/5 * 36 = 14.4

P (diamonds coming in) = 48%

When diamonds don't come in (52%) then you win approximately half the time (too lazy to do a full calc on clubs) or another 26%, so the total chance is approximately 74%, not 90%. You can't add a straight 50% to 48%, you are double-counting the times when diamonds come in.

Later edit:
Note: this assumes clubs are a total guess and that short honor in the LHO is impossible (obviating the guess). In practice I do not think the clubs are a total guess -- LHO should have the ace more often than not for preempting on a jack-high suit, unfavorable.

This post has been edited by eyhung: 2010-January-14, 14:51

[vuroth]

Don't take my word for it, but....

1 - Count me in for AK♦, ♣ to the K. If LHO can bid that way with 5HCP, he's got me.

2 - 4♣ either way.

[quiddity]

eyhung, on Jan 14 2010, 02:15 PM, said:

You can't add a straight 50% to 48%, you are double-counting the times when diamonds come in.

Wow, that was terrible. Thanks for the correction.

[Lobowolf]

How good are my opponents? How about combining the chances of

1) Diamond T with RHO;
2) Diamond Q with LHO; and
3) RHO grabs the Q or tanks when a diamond comes off dummy.

[bid_em_up]

vuroth, on Jan 14 2010, 03:07 PM, said:

Don't take my word for it, but....

1 - Count me in for AK♦, ♣ to the K.  If LHO can bid that way with 5HCP, he's got me.

Unfortunately, North is dealer & opened 1♣, RHO/East bid 2♠, and South has become declarer in 3N.

I think it is quite likely that RHO/East will have both the A♣ and the Q♣ given the vulnerability and the outstanding available cards.

[Siegmund]

I am liking ♦A followed by a diamond to the jack. On a good day ♦Q is onside and we establish the 3rd diamond winner immediately. On a bad day it loses, and when we get back in we run all the hearts before we commit ourselves to either playing for 3-3 diamonds or finessing with the K-9. Given the 6-3 spade break, playing West for 4 diamonds is likely better.