A minor problem

[Walddk]

[hv=d=w&v=b&w=sk63hk53dakj1075c5&e=sq104h72d6cakj9872]266|100|Scoring: IMP

3NT by West.

Lead: H6[/hv]

 

Team match on BBO. Bidding:

 

1♦ - 2♣

2♦ - 3♣

3NT - p

 

Lead: ♥6 to the queen and your king.

 

How do you tackle the minors? I think both declarers got it wrong.

 

Roland

[Echognome]

I believe the best chance in the club suit is to finesse the Jack on the first round. Would look awfully foolish if it's off though as I'd have no sure entry back to dummy.

 

However, it looks like I cannot give up the lead without the defenders scoring 5 tricks first, so I will cash the AK of diamonds and hope the Q falls doubleton (in which case I will just cash my 9 top tricks). If the Q doesn't fall, I will finesse the ♣J.

[TheoKole]

I assume the ♥ lead is forth best, marking opener with an average of 5 hearts,

spades weren't lead so assume 3 or 4 ♠ for opener.

 

I would play the top ♦, to see if the Q ♦ falls, if it does just cash out.

 

Assuming both opps follow to the top ♦'s and the Q ♦ doesn't fall, if you play opener for 3 daimonds, cash the top ♣'s, if you play opener for 2 diamonds, then finesse the J ♣.

 

 

Not much of an answer I know B) , but I would be trying to count the hand at the table in this way, it would help if I knew the opening leader's style of falsecarding or not in this situation (some defenders always falsecard and others rarely do). If I have absolutely no idea at the table I would probably go for the drop by playing the top ♣'s (there is some chance of getting to dummy with the Q ♠.)

 

By the way, I think that the 3NT bid was a mistake, minimum opening misfitting hands should be passed in my opinion.

 

Theo

[david_c]

Seems to be a very close decision whether to try to drop the ♣Q or the ♦Q (nothing else looks remotely attractive). I think it's slightly better to play for the drop in clubs, by about 1% if I have the calculations right. It doesn't look like the inferences from the lead make much difference here.

[Free]

1. Playing for ♦Qx-xxxx or ♣Qx(x) in North = ???%

2. Playing for ♣Qx-xxx or ♦Qx(x) in South = ???%

 

I think line 2 is clearly better since the finesse has exactly the same chance, but Qx-xxx vs Qx-xxxx is better chance (unless I'm completely wrong here).

 

So ♣AK, if the Q drops we make, otherwise finesse ♦ while we're in dummy.

[david_c]

the finesse has exactly the same chance,

I don't think so - the chance of the finesse picking up the suit is higher in clubs than in diamonds.

[PMetsch]

I play ♦AK and ♣finesse. A ♦ finesse would also require ♦3-3.

[Winstonm]

I believe the best chance in the club suit is to finesse the Jack on the first round.  Would look awfully foolish if it's off though as I'd have no sure entry back to dummy.

 

However, it looks like I cannot give up the lead without the defenders scoring 5 tricks first, so I will cash the AK of diamonds and hope the Q falls doubleton (in which case I will just cash my 9 top tricks).  If the Q doesn't fall, I will finesse the ♣J.

I echo echo. B)

[pclayton]

The lead doesn't matter if it 4th or 5th best, as the defenders will take 3H, 1S and the minor we give up when if we lose the lead.

 

Ill try some napkin calcs:

 

1) Dropping QC and then playing on diamonds: (1. QC - Q (in west only or Qx = 9 cases / 32 -30%) + diamond Q,Qx or Qxx = 31%), combined = 51 -52%

 

2)Drop the QD and try clubs: (QD - 12 cases / 64 = 18.75%) + 1/2 of 67% - 33.5= combined = 46% or so.

 

I give the edge to #1.

[Guest Jlall]

doing no calculations, I would play AK of clubs then hook the diamond. Qx off is not that much less likely than Qxx onside, but Qx of diamonds off is significantly less likely than Qxx of diamonds on. Curious to see if the intuitive line is correct mathematically, i'll guess no since both got it wrong at the table.

[Winstonm]

The lead doesn't matter if it 4th or 5th best, as the defenders will take 3H, 1S and the minor we give up when if we lose the lead.

 

Ill try some napkin calcs:

 

1) Dropping QC and then playing on diamonds: (1. QC - Q (in west only or Qx = 9 cases / 32 -30%) + diamond Q,Qx or Qxx = 31%), combined = 51 -52%

 

2)Drop the QD and try clubs: (QD - 12 cases / 64 = 18.75%) + 1/2 of 67% - 33.5= combined = 46% or so.

 

I give the edge to #1.

Singleton Q in clubs doesn't help as RHO will then hold 10xxx and you still only have 3 club tricks. It looks like Qx of clubs in either hand is 27% chance. RHO holding Qxx or Qx of diamonds is 26%.

 

Dropping the Qx of diamonds is 16%. Without 6 diamond tricks, you have to bring in the clubs for no loser which requires Qx or Qxx onside, a 34% chance.

I think. B)

 

Winston

[Guest Jlall]

I asked my friend aaron what he thought. He said it seemed close so we did the math... here's what we got:

 

AK of clubs then diamond finesse caters to Qx of clubs anywhere, or Qxx or Qx of diamonds on. These are 27.13 and 25.84 % (www.rpbridge.net) making the total 45.96 %

 

AK of diamonds then club hook caters to Qx of diamonds anywhere or Qxx or Qx of clubs on. This is 33.91 and 16.15 % (www.rpbridge.net) making the total 44.58 %.

 

Sorry for the ugly numbers, it was close so I didn't want to round too much. AK of clubs then diamond hook is the favorite in isolation...for those who want to factor in the lead good luck. It's impossible to know whether it was a 4 or 5 card suit lead (assuming 4th best) and is pretty complicated

[Fluffy]

catching ♦Q bare migh help you squeeze someone won't it?

[Echognome]

I just ran the numbers and agree with Justin's. It turns out to be a lot like what we call "comparative advantage" in economics. Namely that the club suit offers the best chance in a single suit whether playing for the finesse or the drop. However, the finesse is "relatively" better in diamonds than in clubs.

 

Here's what I mean.

 

Succeed if Finesse Drop

♣'s 33.91 27.13

♦'s 25.84 16.15

 

So the finesse is around 6.8% better in clubs, whereas the finesse is around 9.7% better in diamonds. Thus you want to play clubs for the drop and diamonds for the finesse. It's actually a bit more complicated but the idea is there. Using the above numbers the calculations are:

 

AK clubs then diamond finesse = 27.13% + 72.87%*(25.84%) = 45.96%

AK diamonds then club finesse = 16.15% + 83.85%*(33.91%) = 44.58%

 

Which is what Justin got.

 

I agree that taking into account empty spaces may change these odds but the line should not change. If I assume that LHO has long hearts, then it is MORE likely that RHO has any minor suit cards and thus playing for the drop should be safer.

[Walddk]

[hv=d=w&v=b&n=sa92hj9864d832c63&w=sk63hk53dakj1075c5&e=sq104h72d6cakj9872&s=sj875haq10dq94cq104]399|300|Scoring: IMP

3NT by West

Lead: H6[/hv]

 

3NT by West.

Lead: ♥6 to South's queen and West's king.

 

Here is the full deal. It was a push board in the match when both declarers finessed ♣J without testing diamonds first and went 2 down. Third best line it seems. My learned colleagues have concluded that it's slightly better to cash ♣AK, and if no queen appears then rely on the diamond finesse.

 

That would lead to 9 tricks on this layout. The theme (somewhat simplified) is actually well known if you think about it.

 

- 1. Go for the drop in the suit where you have 8 cards between you.

- 2. If no luck, finesse in the suit where you have 7 cards.

 

Roland

[Double !]

am aware of the concept of playing for drop in the longer suit, finesse in the shorter. Many have published deals on this theme.

 

However, I find it VERY interesting that the numbers that matt, justin, and aaron got for success for playing for drop in clubs/ finesse diamonds vs. playing for drop in diamonds/ finesse in clubs in isolation are so close.

[Rebound]

I admit I got it wrong. Thanks for this post, it's always good to learn something new.

[Chamaco]

At first I thought AK of clubs, if Q does not drop, then finesse diamonds, to combine chances, as many similar situations are quited in cardplay handbooks on % plays.

 

Then I did the math.

 

The chances are:

 

Dropping Qx of clubs = 2/5 of the 3-2 splits = 0.4*68 = 26.6

Dropping Q stiff = 1/5 of 4-1 splits (28%) = 5.6

Total chances of dropping club Q = 32.2

 

Finessing diamonds works with:

Qxx onside = 50% of 3-3 splits = 18%

Qx onside = 1/3 of the FAVOURABLE 4-2 splits (which is 24%, the half of all 4-2 splits) = 8%

Q stiff onside = 1/5 of the FAVOURABLE 5-1 split (7.27 %) = 1.4 %

The overall probability of picking the diam Q by a 1st round fimesse is then = 27.4

 

only if Qxx of diamonds onside = (chances of Q onside) * (chances of 3-3 split ) = (50%)* (36%) = 18%.

 

The chances that both chances fail is the product of the % = [(100-32.2)/100] * [(100-26.8)/100] = 0.678 * 0.726 = 49.22 % chances of failure.

 

----------------------------------------------

 

EDITED by Chamaco

 

My previous calculation contained errors. Hope these are better.

It seems after all trying dropping the club Q is slightly superior to a first round finesse.

 

----------------------------------------------

 

3rd solution is trying AK of diamonds first and then finessing clubs.

 

Chances for DQ dropping:

Qx of diamonds = 16%

Q stiff of diamonds = 2.8 % (this time we do not care which 51 beak we get)

Chances of dropping DQ = 18.8

 

Chances of club finesse picking up the suit = 1/2 of overall 3-2 splits = 34 %

 

Chances of both failing = 0.812 * 0.66 = 53.592 % of failure

[inquiry]

I did some quick math rounding off, and drawing no inference from any play... and agree that this is a slight paradox. The odds favor cashing the ♦AK first, then if that fails, take the first round club finessee.

 

I get,

♦ first ~ 53.9%

♣ first ~51%

 

I haven't check Chamaco's math, but these numbers are close enough to his for me to believe I made a rounding error (mine are slightly higher than his, but the concluson and order of magnitude are the same. ).

[Guest Jlall]

I don't agree with your numbers.

 

Please remember stiff queen in either suit is not good enough, but your numbers are still off.

 

www.rpbridge.net will give you exact numbers to the hundredth

[Winstonm]

I don't agree with your numbers.

 

Please remember stiff queen in either suit is not good enough, but your numbers are still off.

 

www.rpbridge.net will give you exact numbers to the hundredth

I checked the numbers also with known 1-1 hearts in opps hands the only available information. Singleton Q in either suit was ruled out.

 

Drop the club Qx=27%

Find Qx, Qxx Diamonds onside: 26%.

 

Drop the Qx of diamonds: 16%

Find Qx or Qxx clubs onside: 34%

 

Being no mathematician, I believe though that to calculate the odds one must use this method:

 

Drop the Diamond or finesse in clubs: 16%+(34%x84)=44.56%

Drop the Club or finesse in diamonds: 27%+(26%x73)=45.98%

 

You math whizzes may correct me - this is as good as a "Dumb Okie" can do. :lol:

 

Winston

[david_c]

I also get 44.6% (try to drop the ♦Q then finesse in clubs) and 46.0% (try to drop the ♣Q then finesse in diamonds), doing the calculation by treating the minor-suit distributions as independent.

 

If you take into account the fact that the minors aren't independent then you will find that the difference between the two lines is only about 0.8%, but it still favours playing to drop the ♣Q.

 

But all this accuracy is a bit misleading because of the lead inferences, though you would still expect that playing for the ♣Q to drop is better. For example, if you do the calculation under the assumption that the opening leader has precisely 5 hearts, then starting with the top clubs is better by about 1.8%.