Finesse D?

[kgr]

[hv=pc=n&s=skhq52dj98642cakt&n=sqj2hak73daq73c62&d=s&v=0&b=11&a=1d(4%2B)p1hp2dp4dp4hp5dp6dppp]266|200|MP's[/hv]

Small ♣ lead for ♣Q and ♣A.

Is it best to finesse ♦ OR play ♦A and hope for ♦K singleton or ♥3-3?

[eagles123]

I would've thought Ace diamond better but just a gut feeling

[wanoff]

It's better to finesse ♦J by quite a bit.

Give yourself ♥J and it's a lot closer though I think I might still finesse.

[MrAce]

Finesse is right of course

 

You can try to drop K and if it does not drop you can try for 3-3 hearts (assume you played a dia and LHO followed small)

 

Dropping K is % 13

3-3 ♥ is % 38

Combined chance are % 33 (is this true? It's been long time http://www.bridgebase.com/forums/public/style_emoticons/default/tongue.gif)

 

Finesse is % 37 for the relevant cards (I do not count K stiff onside)

[MrAce]

It's better to finesse ♦J by quite a bit.

Give yourself ♥J and it's a lot closer though I think I might still finesse.

 

♥ J changes much more than you think. After K did not drop you are not only making on 3-3 hearts but any heart split as long as the last trump hand holds longer hearts.

[MrAce]

I think I overlooked the fact that in the case of 3-0 trump break, 3-3 hearts won't help. So Wanoff may as well be correct that even with ♥ J, finnesse can be right. I am sure one of our math guys/gals will tell the precise % for it.

[WesleyC]

The finesse is the better option 50% vs 45%.

 

The win chance playing for drop is given by:

 

26% (chance of singleton king)

and

52% (chance of Kx in either hand) * 36%* (chance of 3/3 hearts).

 

You might also get a slight extra chance if trumps are 3-0 and they don't cash the As

 

-----

 

If you also had the J♥ then your chance of playing for the singleton would also pickup 4/2 5/1 6/0 hearts with 2/1 trumps.

This swings the odd significantly

 

26% + 52% * 63.5% (chance of 3+ hearts with the long diamonds) = 59%

[kgr]

Thanks you all for the answers.

I didn't matter in this deal because both finesse worked & Hearts 3-3, but I was curious what was the best line.

[MrAce]

The finesse is the better option 50% vs 45%.

 

The win chance playing for drop is given by:

 

26% (chance of singleton king)

and

52% (chance of Kx in either hand) * 36%* (chance of 3/3 hearts).

 

You might also get a slight extra chance if trumps are 3-0 and they don't cash the As

 

-----

 

If you also had the J♥ then your chance of playing for the singleton would also pickup 4/2 5/1 6/0 hearts with 2/1 trumps.

This swings the odd significantly

 

26% + 52% * 63.5% (chance of 3+ hearts with the long diamonds) = 59%

 

Isn't it a mistake to add K stiff onside? Because we already played a dia towards dummy and saw LHO can not have a stiff K.

[WesleyC]

Isn't it a mistake to add K stiff onside? Because we already played a dia towards dummy and saw LHO can not have a stiff K.

 

My solution essentially looked at all the possible layouts before any cards have been played at all and then worked out on how many of those layouts each strategy was going to succeed. This is usually called the 'a priori' chance. In this example Stiff King onside is included as a win for both strategies and Kxx offside is included as a loss.

 

You could calculate the chance of success at a different point (e.g. after LHO has followed low to the first diamond or after you dropped the Stiff King dropped offside). At this point some possibilities have been eliminated and the chance of success might be different, but when comparing a simple strategy like drop vs finesse that can't be varied, you won't get a more meaningful answer.

[nige1]

[hv=pc=n&s=skhq52dj98642cakt&n=sqj2hak73daq73c62&d=s&v=0&b=11&a=1d(4%2B)p1hp2dp4dp4hp5dp6dppp]266|200|

MP's Small ♣ lead for ♣Q and ♣A. Is it best to finesse ♦ OR play ♦A and hope for ♦K singleton or ♥3-3?

[/hv]

WesleyC seems correct..

• Running ♦J works when LHO has ♦K = about 50%.
• Cashing ♦A works when ♦K is singleton or (♦K is doubleton and ♥ are 3-3) = 26% + (52% * 36%) = about 45%

[kgr]

Thank you all for the answers!

The finesse is the better option 50% vs 45%.

 

The win chance playing for drop is given by:

 

26% (chance of singleton king)

and

52% (chance of Kx in either hand) * 36%* (chance of 3/3 hearts).

 

You might also get a slight extra chance if trumps are 3-0 and they don't cash the As

 

-----

 

If you also had the J♥ then your chance of playing for the singleton would also pickup 4/2 5/1 6/0 hearts with 2/1 trumps.

This swings the odd significantly

 

26% + 52% * 63.5% (chance of 3+ hearts with the long diamonds) = 59%

After the lead the probability that LHO has ♦K will be higher than 50% because he didn't lead ♦.

Maybe even enough to still finesse ♦ if we would have J♥

[PhilKing]

Isn't it a mistake to add K stiff onside? Because we already played a dia towards dummy and saw LHO can not have a stiff K.

 

That's partly balanced by West not showing out. The finesse is slightly odds against. And it's worst against a very weak defender, who might cover the ♦J with KTx.

[MrAce]

That's partly balanced by West not showing out. The finesse is slightly odds against. And it's worst against a very weak defender, who might cover the ♦J with KTx.

 

I assume you are talking about when we hold ♥J

[nige1]

[hv=pc=n&s=skhq52dj86542cakt&n=sqj2hak73daq73c62&d=s&v=0&b=11&a=1d(4%2B)p1hp2dp4dp4hp5dp6dppp]266|200| PhilKing hints at another amusing wrinkle. Suppose that you are missing ♦KT9, playing 6♦ on a ♣ lead. Now the finesse is inferior...

- The finesse wins when LHO has: singleton ♦K, doubleton ♦Kx, or (♦KT9 and 3 ♥s) = 13% + 26% + (11% * 36%) = about 43%

- Cashing ♦A wins when ♦K is singleton or when (♦Kx is doubleton and ♥ are 3-3) = 26% + (52% + 36%) = about 45%.

- Even when intending to cash ♦A, you should still lead ♦J from hand, in case LHO makes the mistake of covering with ♦KT9 and 3 ♥s. If LHO would cover to preserve his trump trick, that increases your odds to about 49%. [/hv]

[PhilKing]

I assume you are talking about when we hold ♥J

 

I just mean that the finesse is slightly worse than 50% - I was not comparing the two lines. They are probably close enough that you need to be at the table to decide whether to try the combo play.

[lamford]

I don't know how you can conclude the diamond finesse is slightly odds against. West might have led a spade if the diamond finesse was losing; certainly if he is looking at the ace of spades he should, so I think the diamond finesse is a favourite if anything. The chances of stiff king of diamonds or hearts 3-3 and diamonds 2-1 seems to be around 43% anyway, so this one does not look close.

[MrAce]

I don't know how you can conclude the diamond finesse is slightly odds against. West might have led a spade if the diamond finesse was losing; certainly if he is looking at the ace of spades he should, so I think the diamond finesse is a favourite if anything. The chances of stiff king of diamonds or hearts 3-3 and diamonds 2-1 seems to be around 43% anyway, so this one does not look close.

 

Why do you think W knew the location of ♦ A? If anything, he would think that S is more likely to have it, thus he would have cashed spade A if he had it + ♦K, no?

[kgr]

Please let me know if below calculation is not correct:

 

After having played a small Diamond and West follows with D2.

KT2 - 11 11

KT 2 13

K2 T 13 13

K T2 13

T2 K 13 13

T K2 13

2 KT 13 13

- KT2 11

Only the possibilities with West having D2 are still valid.

This gives:

 

For playing the DA:

- East single DK: 26%

- East T singleton or KT Doubleton: 52% ; with H 3-3: 52%*36%=19%

=> 45%

 

For Finesse:

- West DK2: 26%

- West DKT2: 11% ; with H 3-3: 11%*36%=8%

=> 34%

What is wrong with this..or is playing DA better anyway?

[MrAce]

Please let me know if below calculation is not correct:

 

After having played a small Diamond and West follows with D2.

KT2 - 11 11

KT 2 13

K2 T 13 13

K T2 13

T2 K 13 13

T K2 13

2 KT 13 13

- KT2 11

Only the possibilities with West having D2 are still valid.

This gives:

 

For playing the DA:

- East single DK: 26%

- East T singleton or KT Doubleton: 52% ; with H 3-3: 52%*36%=19%

=> 45%

 

For Finesse:

- West DK2: 26%

- West DKT2: 11% ; with H 3-3: 11%*36%=8%

=> 34%

What is wrong with this..or is playing DA better anyway?

 

First of all you need to start ♦ J, not small. It won't cost anything, but As Phil said someone may cover from KTx.

2nd, E holding stiff K is not % 26, it is % 13

[PhilKing]

I don't know how you can conclude the diamond finesse is slightly odds against. West might have led a spade if the diamond finesse was losing; certainly if he is looking at the ace of spades he should, so I think the diamond finesse is a favourite if anything. The chances of stiff king of diamonds or hearts 3-3 and diamonds 2-1 seems to be around 43% anyway, so this one does not look close.

 

West might have led a spade if the diamond finesse were winning, with or without the ace (he is not clairvoyant).

 

Besides, you have taken my "conclusion" out of context, which was in reply to the post excluding stiff king onside from the equation.

[kgr]

Please let me know if below calculation is not correct:

 

After having played a small Diamond and West follows with D2.

KT2 - 11 11

KT 2 13

K2 T 13 13

K T2 13

T2 K 13 13

T K2 13

2 KT 13 13

- KT2 11

Only the possibilities with West having D2 are still valid.

This gives:

 

For playing the DA:

- East single DK: 26%

- East T singleton or KT Doubleton: 52% ; with H 3-3: 52%*36%=19%

=> 45%

 

For Finesse:

- West DK2: 26%

- West DKT2: 11% ; with H 3-3: 11%*36%=8%

=> 34%

What is wrong with this..or is playing DA better anyway?

 

 

First of all you need to start ♦ J, not small. It won't cost anything, but As Phil said someone may cover from KTx.

2nd, E holding stiff K is not % 26, it is % 13

In my calculation I used 13% for stiff DK with RHO, but only 50% of combinations are still possible after D2 with LHO... this gives 26%; or is that completely wrong?

[PhantomSac]

I am rather embarrassed my instinct was the combo play (which is usually what I would do on a math hand irl). Proving once again that I am bad at the close math hands and that experts have too much inclination to combine chances rather than to commit. But in my defense their failure to bid probably brings the combo play up, they do have 9 spades and 11 points as well as 8 clubs and both had the chance to overcall 1S white, I think 3-0 diamonds becomes less likely than usual and stiff king becomes more likely than usual (because stiff K is generally a reason not to bid and Kx/stiff are both fine holdings for bidding, as are KTx/void obv). Maybe I am just making excuses for my failure though ;)

 

Also just noticed it was MP, the diamond hook gives us a better shot at an overtrick, not that that is the priority but it counts for something in a close decision.

[MrAce]

 

 

For playing the DA:

- East single DK: 26%

- East T singleton or KT Doubleton: 52% ; with H 3-3: 52%*36%=19%

=> 45%

 

See the bolded in quote. You show DK single with E possibility as % 26, which is not true.

[MrAce]

Kgr, we are comparing 2 lines as you asked in the OP. It is important that you start with ♦J. Once you do that, W holding

 

KTx

KT

Kx

 

%11+13+13=37 Finesse wins regardless of how hearts are split. Once it works your slam is at home.

 

K-Tx

Void-KTx

 

are irrelevant splits, they are wash.

 

x-KT

T-Kx

Tx-K

 

%13+13+13 =39. So playing the Ace would be winner by a very small margin IF it did not need 3-3 heart break. Unfortunately, it does also need 3-3 ♥ break.