Suit Combination

[Cascade]

KQ109xx

 

xx

 

What is the best play ?

 

I am getting myself confused.

 

Fred says lead to the King and then to the Queen in one of the BridgeMaster deals. This concurs with SuitPlay but Rudinesco seems to say finesse the ten then the nine.

 

Anyway I am now officially confused and any help would be appreciated.

 

Thanks

[Sigi_BC84]

I haven't calculated it myself, but if we can trust Suitplay not to emit wrong figures (which would mean that its programmer has made serious mistakes) then I would say: go with Suitplay. Fred being of the same opinion should only reconfirm you in that decision.

 

There should be no reason to be confused in my eyes.

 

--Sigi

[whereagles]

From this odds calculator, you get

 

Roudinesco: wins 48%

Suitplay: wins 53%

 

(You can check it out yourself by ticking boxes along the three columns to the right.)

 

However, I know Roudinesco is a very careful person. I can hardly believe he made a mistake here.. Are you sure you were looking for in the right place?

[Cascade]

From this odds calculator, you get

 

Roudinesco: wins 48%

Suitplay: wins 53%

 

(You can check it out yourself by ticking boxes along the three columns to the right.)

 

However, I know Roudinesco is a very careful person. I can hardly believe he made a mistake here.. Are you sure you were looking for in the right place?

Chapter 11 (25) b pg 310

 

xx

 

KQ109xx

 

...

 

MAX and N 4 ... (1/2) Finesse the nine and ten.

[42]

playing low to KQ (if successful --> :) )

 

AJxxx .... --- B)

AJxx ...... x speaks for an immediate finesse :(

Axxx ..... J :)

AJx ..... xx :)

Axx..... Jx :)

AJ..... xxx :)

Ax ..... Jxx :)

A ..... Jxxx :(

Jxxx..... A speaks for an immediate finesse :(

Jxx ..... Ax :(

Jx ..... Axx :)

J ..... Axxx :)

xxx ..... AJ :)

xx ..... AJx :(

x ..... AJxx :(

--- ..... AJxxx :(

 

Did I forget or overlook something? So it looks as if one can play either way: 8 :), 8 :(

[Chamaco]

Jxx ..... Ax :(

This layout would be picked up by the 2nd round finesse (low to the T), which I believe (correct me if wrong) is the % followup if the K loses to the Ace offside. B)

[hatchett]

This layout would be picked up by the 2nd round finesse (low to the T), which I believe (correct me if wrong) is the % followup if the K loses to the Ace offside.

 

But RHO might duck the Ace on the first round....

[Chamaco]

This layout would be picked up by the 2nd round finesse (low to the T), which I believe (correct me if wrong) is the % followup if the K loses to the Ace offside.

 

But RHO might duck the Ace on the first round....

 

Of course.

this would not be the first nor the last time one pays off to a falsecard.

 

Having said that, I think the option of RHO falsecarding does not change the fact that - theoretically - it is slightly the better % to play low to the K and if it loses, low to the T at second round.

 

This, from the theoretical viewpoint; but lots of better players than myself have commented on the role of "table feel", which is often used by experts when two lines' percentages differ by very little.

 

Nonetheless, this thread was - I think - on the *theoretical* analysis of this card combo.

[whereagles]

From this odds calculator, you get

 

Roudinesco: wins 48%

Suitplay: wins 53%

 

(You can check it out yourself by ticking boxes along the three columns to the right.)

 

However, I know Roudinesco is a very careful person. I can hardly believe he made a mistake here.. Are you sure you were looking for in the right place?

Chapter 11 (25) b pg 310

 

xx

 

KQ109xx

 

...

 

MAX and N 4 ... (1/2) Finesse the nine and ten.

Weird.. well, I dunno. Maybe you can send him an email B)

[Blofeld]

Finessing the ten and then the nine definitely looks better needing 4 tricks, and feels wrong needing 5 - could they both be right for different problems?

[Fluffy]

Having said that, I think the option of RHO falsecarding does not change the fact that - theoretically - it is slightly the better % to play low to the K and if it loses, low to the T at second round.

I think we have talked about a similar suit before, and it was said that a perfect defender would win ♠K only on 2 cases: bare A, and AJ bare, then playing low to the Q even if it losed is still better.

[hatchett]

Having said that, I think the option of RHO falsecarding does not change the fact that - theoretically - it is slightly the better % to play low to the K and if it loses, low to the T at second round.

 

I'm not sure I'd call ducking the King with Ax a falsecard; but anyway, if you finesse on the second round after the ace is taken you lose to AJ.

Of course it depends how often RHO wins the A from Ax. I think to calculate the correct theoritical line you have to assume an optimal strategy by the defence.

[cherdano]

playing low to KQ (if successful --> :( )

 

AJxxx .... --- B)

AJxx ...... x speaks for an immediate finesse :(

Axxx ..... J :(

AJx ..... xx :)

(...)

Did I forget or overlook something? So it looks as if one can play either way: 8 :), 8 :(

Caren, you missed two things: You should compare this list with the list of successes of the direct finesse. Also, some of these layouts are really several layouts, because there are several ways the small cards can be distributed. So it go s.th. like this:

 

AJxxx ... -- :(

AJxx ... x :( :( :( (3 layouts)

etc.

 

Arend

[hatchett]

Did I forget or overlook something? So it looks as if one can play either way

 

42 Not all your combinations have equal probability

 

for instance AJxx x is more likely than Axxx J and so on

[Chamaco]

Having said that, I think the option of RHO falsecarding does not change the fact that - theoretically -  it is slightly the better % to play  low to the K and if it loses, low to the T at second round.

I think we have talked about a similar suit before, and it was said that a perfect defender would win ♠K only on 2 cases: bare A, and AJ bare, then playing low to the Q even if it losed is still better.

Hmm, sounds weird. :huh:

 

It i true that a good defender will very often not cover, but:

 

a. at least the same amount of time, he won't cover just because he does not have the Ace LOL (see restricted choices)

 

b. in many cases when he could cover but it not covering would be better, taking the suit in isolation, he might have other reasons to get in quickly and open a sidesuit.

Yes, this falls otside of the "theoretical analysis" in isolation, but still,, it seems to me that - despite the fact that RHO playing low does not guarantee he does not have the Ace - there will be > 50% chances that he indeed won't have it.

 

Indeed, the reason of many defensive falsecards is to induce declarer to play according to the % play :)

But the fact that a falsecard is possible does not mean - IMO - that we shuld refrain from making the % play (unless "table feel" comes into play): that would be equivalent to bidding weird in eeach and every boeard just for fear of a psyche LOL

 

Just thinking aloud, actually I'll be happy to change my mind and learn something from this :-)

[hatchett]

Fred says lead to the King and then to the Queen in one of the BridgeMaster deals. This concurs with SuitPlay but Rudinesco seems to say finesse the ten then the nine.

 

I have looked at Roudinesco and he does not say this! He says finesse the 10 and 9 if the hand under the KQT9xx is presumed to have length. With no length presumption Roudinesco starts off with low to the K and his next play if it wins depends on who you think the strong side is.

[joshs]

I think I am missing something in this thread. If the suit is 3-3, both plays are equally likely to succeed (assuming the ace is always ducked). If the suit is 4-2 you can pick up Jx in either hand by playing to the K and Q, but can only pick up Ax offside when playing to the T9. again this assumes best defense of always ducking the ace at the first trick.

 

Hence, playing to the KQ picks up one more case.

[cherdano]

I think I am missing something in this thread. If the suit is 3-3, both plays are equally likely to succeed (assuming the ace is always ducked). If the suit is 4-2 you can pick up Jx in either hand by playing to the K and Q, but can only pick up Ax offside when playing to the T9. again this assumes best defense of always ducking the ace at the first trick.

 

Hence, playing to the KQ picks up one more case.

Director!

For your convenience, the hands were xx opposite KQT9xx. :huh:

[JohnnyH7]

http://forums.bridgebase.com/index.php?sho...mbination&st=30 is where this suit combination was discussed last.

[42]

Caren, you missed two things: You should compare this list with the list of successes of the direct finesse. Also, some of these layouts are really several layouts, because there are several ways the small cards can be distributed.

Arend

UAAAAARRRGGHHHHHHHHH That drives me crazy, I know again why I am only secretary for and no mathematician myself....

For the small cards: why do they matter since I cover them all? With both honors at least third behind or 1 honor fourth I cannot do anything but losing 2 tricks, independent of the small cards, or? I thought before if I should make 3 sad smilies for AJxx ... x but thought it doesnt matter. And wouldn't I have to make a third list with mixed strategy (the example that Mauro gave: with Jxx ... Ax first low to KQ, then low to 109)? If I edit my list how you said it is correct (or how I understood your hint), does it then look like this?

 

(2 times low to KQ / 2 times low to 109 / 1. low to KQ, 2. low to 109 )

 

AJxxx .... --- (1-/1-/1-)

AJxx ...... x (3-/3+/3-)

Axxx ..... J (1+/1-/1+)

AJx ..... xx (3+/3+/3+)

Axx..... Jx (3+/3-/3-)

AJ..... xxx (1+/0/0) low to the 10 might have been the will *hehe* No error possible

Ax ..... Jxx (3+/3-/3-)

A ..... Jxxx (1-/1-/1-)

Jxxx..... A (1-/1+/1-)

Jxx ..... Ax (3-/3+/3+)"mixed strategy" good if defender ducks the A first

Jx ..... Axx (3+/3+/0) mixed strategy impossible

J ..... Axxx (1+/0/0) no error possible

xxx ..... AJ (1+/1-/1-)

xx ..... AJx (3-/3-/3-)

x ..... AJxx (3-/3-/3-)

--- ..... AJxxx (1-/1-/1-)

 

Now I count:

16+ : 16- for low to KQ

13+ : 17- against low to 109

7+ : 20- against mixed strategy

 

The winner is: low to KQ!

I am really excited now LOL

 

Is this calculation ok this way?????

Can anyone figure that out at the table?

[Sigi_BC84]

Caren, you missed two things: You should compare this list with the list of successes of the direct finesse. Also, some of these layouts are really several layouts, because there are several ways the small cards can be distributed.

Arend

UAAAAARRRGGHHHHHHHHH That drives me crazy, I know again why I am only secretary for and no mathematician myself....

For the small cards: why do they matter since I cover them all?

The point Arend was making is the following:

 

If you enumerate holdings and write, for example, AJxx x, then actually you have just specified more than one specific holding. It becomes clearer if you pick real spot cards for the 'x'es or pick distinct variable names, as in:

 

"AJab c" -- now a, b and c are three different cards (for example "AJ73 5", but this looks as if the values of the spots did matter).

 

Now consider just the three small cards: they can be distributed as "ab c", "ac b" and "bc a". So when writing "AJxx x" you have to count 3 hands, not one...

 

This fact is hidden when writing "x" for any spot card, because that looks at first sight as if all the xes are equal, in which case ordering would not matter.

 

--Sigi

[Cascade]

Fred says lead to the King and then to the Queen in one of the BridgeMaster deals. This concurs with SuitPlay but Rudinesco seems to say finesse the ten then the nine.

 

I have looked at Roudinesco and he does not say this! He says finesse the 10 and 9 if the hand under the KQT9xx is presumed to have length. With no length presumption Roudinesco starts off with low to the K and his next play if it wins depends on who you think the strong side is.

You are right. I misinterpreted the "& East = PLS" and I missed the "(;) N 5 ..." solution higher in his text.

 

What he says is

 

"(:) N 5 Lead to the queen. If it loses (2) Finesse the ten. If it holds, either (2) Lead to the King (East = P Str S) or (2) Finesse the ten (West P Str S)."

 

This is still different than Fred and SuitPlay who both say play to the King and then to the Queen if the King holds.

[Fluffy]

That is probably because leading to the K and Q is better in theory, but in practice against any kind of defender, the % changes and low to the 10 becomes better (the only differencec between the 2, I think is one pitches AJ, and the other bare A, but since chance of 1 case of 3-2 is a little bit higher than 4-1 K, then Q is better only in theory).

 

SuitPlay thinks of defenders to play 100% perfect. Probably Roudinesco assumes they don't (and he is correct IMO :rolleyes:)

[Stephen Tu]

Roudinesco in fact mentions the Suitplay line, under "var 2". Basically low to K then low to Q is best if the defender will always duck with Ax behind it, best defense. If there are clues from the auction, or the defender isn't that good, consider something else ...