AKQ9xx vs xx

[whereagles]

falsecard percentage with mathematical proof?, sounds like military inteligence :)

the kind that sent 300 000 troops to eye-rak

 

and which might send more into eye-ran :(

[manudude03]

If you desperately needed it played for no losers, then I would cash the K as well. If both opps follow then the Q will drop the remaining trump. If it splits 4-1 offside, there's nothing you can do apart from maybe endplay them assuming you haven't lost a trick already. If it splits 4-1 onside, then cashing the K will find that out and then you will have to hope you can force them to ruff under you (ruff winners if you have to)

[foo]

falsecard percentage with mathematical proof?, sounds like military inteligence :(

It really is very simple. Say you are playing the 1st board vs. a total stranger when this situation comes up. What is the right thing to do?

 

The math shows that apriori there is a 23% chance that LHO Falsecarded.

Thus playing LHO to have Falsecarded is not the percentage action.

 

Therefore, get a better count on the hand before commiting oneself if you can, but the evidence =at this point= is that you should play for split honors.

 

Any plan of play that differs from this is not based on Bridge logic. It is based on table feel and other such psychological considerations.

 

Why Justin calls this elementary exercse in mathematical logic "hopeless" is beyond me.

[jdonn]

Why Justin calls this elementary exercse in mathematical logic "hopeless" is beyond me.

And that's what makes this so funny lol.

[han]

Sadly enough, it is the mathematical abuse by people who don't have a clue that gives mathematicians a bad name. I hope dburn isn't reading foo's "mathematics".

[Stephen Tu]

And even if you loose, you may earn their respect

 

No, I just laugh at them in my head for insulting me. Same when they play Axxx opposite Q9xx by ace then ducking after I follow low 2nd hand from KTx/KJx (which I'll do whenever I don't think I need the tempo or need to avoid endplay, after being pissed off too many times when their theoretically flawed play picked off my JTx).

 

And BTW Marlowe it's spelled "lose"; "loose" is a word with a different meaning (opposite of tight) that would rarely be used in a bridge context. I know English isn't your first tongue, but it seems 90% of the native English speakers get this wrong also online, it drives me nuts. Please be better than them :).

 

The math shows that apriori there is a 23% chance that LHO Falsecarded.

Thus playing LHO to have Falsecarded is not the percentage action.

 

Foo, your math is hopeless. You are counting Jx as a losing case for the drop. The drop doesn't lose there! It only matters what you do if LHO has JT, J, or JTx. Jx/Jxx doesn't matter as both lines win. JTxx doesn't matter since both lines lose. So the only thing that matters is whether LHO will play J from JTx/JT often enough to be > stiff J, which depends on your estimate of opponent's tendencies. Counting irrelevant cases is stupid, it just adds the same success/fail percentages to both sides, which won't change the comparison.

 

If you want to insist that 23% is the number you should use as justification against the drop (actually should be half that, since supposedly the falsecard should be the T half the time), I'll counter with "LHO only has stiff J 6.25% of the time so you shouldn't hook against someone who can falsecard", since 6.25% < 0.5(23). And I haven't even yet counted the JT case which makes it even better for the drop.

Hooking only wins if LHO has stiff J! It's only better than the drop when the opponent doesn't know to falsecard from JTx, so that the "23%" estimate drops down to say < 2%.

[Halo]

Weird post.

 

Maybe everyone inclduing Stephen and Jlall can just respond to the question.

 

Jack falls.

 

Drop = A

Finesse = B

 

A or B

 

Let's forget all the words and the 'wtp'. Leave foo alone. Answer the question.

[Stephen Tu]

The answer's been stated clearly many times already in this thread. Just we've had to deal with foo injecting his nonsensical arguments.

 

Again:

- against an opponent who you think knows that he is supposed to play J or T from JTx and will play one of the honors at least 23% * the 10.17% of time he has this holding, play for the drop.

- against someone who can't even think of why one would want to play J or T from JTx, and would always play x, play for the hook.

 

That's clear. What's not clear in my mind, since I have insufficient sample size, is what percentage of people fall into category 1, can falsecard, vs. category 2, can't falsecard, in :

- typical club game

- typical sectional/regional

- typical NABC+ event 1st/2nd/3rd day

 

Anybody have ballpark estimates? One problem with going for the hook is that your edge is fairly small vs. what you lose if you are wrong about your man, so if dealing with an unknown opp you have to feel like he is 85% in category 2 before it's +EV to hook.

[Guest Jlall]

Hi Stephen,

 

Good question. I would say that your average unknown player in a club/sectional/regional/NABC day 1 has a very low chance of being the type to falsecard. I may be biased in that I feel like I know the good players from my area, so if I don't know them there is a good chance that they are not very good (this could be wrong if they have moved/dont often play live/whatever). You can also look for other factors such as:

 

Are they young? (I would be inclined to think they could falsecard)

Do they have a kibitzer?

Are they at a seeded table?

Do they play complicated methods (I think this increases the chance that they know about mandatory falsecards, though obviously it's a generalization)?

If it is not the first board of the round, did they play competently on the other round?

Are they watching whats happening or just playing their card and turning it over quickly?

Are they foreign?

 

These things are not foolproof but are clues at least.

 

If it was day 2 of an NABC or higher I would assume they could falsecard.

[foo]

Weird post.

 

Maybe everyone inclduing Stephen and Jlall can just respond to the question.

 

Jack falls.

 

Drop = A

Finesse = B

 

A or B

 

Let's forget all the words and the 'wtp'. Leave foo alone. Answer the question.

With no other information to go on; the percentage action in this situation to believe the J is an honest card and therefore to pursue plan B, to take the finesse.

 

It does not matter whether LHO is a stark novice or Paul Soloway.

 

If you make the decision to play for the drop here, line A, without any further information, you are not making that decision based on any form of probability or card logic. You are making that decision based on non mathematical factors like table feel or some other psychological factor.

 

There's nothing wrong with that, but it is not the technically correct play and no amount of noise to the contrary by people attempting to misuse math attempting to make it the technically correct play is going to make it so.

 

Deciding to play LHO to have Falsecarded here is simply not a decision based on technical grounds.

[Guest Jlall]

Any way to ban foo from posting in adv/exp forum? Seriously this is completely ridiculous.

 

Foo you are a stubborn novice who thinks he is an expert. There is nothing worse. You do not belong here. Go play on the short bus.

[Stephen Tu]

Foo, you are just completely out to lunch here.

 

It does matter if you are playing someone of the caliber of the late Paul Soloway.

Say you play the hand 1000 times and take the hook each time.

I on the other hand will play for the drop.

 

He will hold the stiff J about 28 times. you win here, I lose.

He will hold the JT doubleton 34 times, playing the J about 17 times. I win these while you lose.

He will hold the JTx 102 times, playing the J half or 51 times. I win these also, you lose.

 

Don't you see that 51 + 17 > 28?

 

If you want to throw in the Jx/Jxx combos (which won't happen in practice since those are silly plays if partner has Qxx/Qx), then fine, we both win those, they are irrelevant.

 

 

 

Deciding to play LHO to have Falsecarded here is simply not a decision based on technical grounds

It is absolutely the right mathematical play to play for the drop if you think a falsecard is possible. The hook only helps you if LHO started with a stiff J. It only hurts you if he held JT doubleton or JTx and he chose to play the J. The latter is mathematically more probable than the former as long as your opponent plays J from JTx an appreciable (11+% or so) amount of the time he is dealt that combo.

[Fluffy]

falsecard percentage with mathematical proof?, sounds like military inteligence :D

It really is very simple. Say you are playing the 1st board vs. a total stranger when this situation comes up. What is the right thing to do?

 

The math shows that apriori there is a 23% chance that LHO Falsecarded.

I don't know how YOUR math works, I think you are guessing the opponent since its unknown, he will play a random card.

 

Well, by the time you realised that the opponent is cappable of talking the 23% is already wrong.

 

If he is capable of using bidding boxes then it changes again

 

If he had ordered a sandwich just before playing the card you might think he is not concentrated when he plays the card. It changes teh odds again.

 

Enuff to say humans are not predictable.

[Halo]

The answer's been stated clearly many times already in this thread. Just we've had to deal with foo injecting his nonsensical arguments.

 

Again:

- against an opponent who you think knows that he is supposed to play J or T from JTx and will play one of the honors at least 23% * the 10.17% of time he has this holding, play for the drop.

- against someone who can't even think of why one would want to play J or T from JTx, and would always play x, play for the hook.

 

That's clear. What's not clear in my mind, since I have insufficient sample size, is what percentage of people fall into category 1, can falsecard, vs. category 2, can't falsecard, in :

- typical club game

- typical sectional/regional

- typical NABC+ event 1st/2nd/3rd day

Stephen

 

Glad to see you have taken up Bridge, and the behaviour of opponents is now unlcear to you.

 

But then that is the game.

[mikeh]

Hi Stephen,

 

You can also look for other factors such as:

 

Are they young? (I would be inclined to think they could falsecard)

Do they have a kibitzer?

Are they at a seeded table?

Do they play complicated methods (I think this increases the chance that they know about mandatory falsecards, though obviously it's a generalization)?

If it is not the first board of the round, did they play competently on the other round?

Are they watching whats happening or just playing their card and turning it over quickly?

Are they foreign?

 

These things are not foolproof but are clues at least.

 

If it was day 2 of an NABC or higher I would assume they could falsecard.

As an old fogey who probably knew and used this falsecard before you were born, Justin, I'd like to get morally indignant!

 

But I am going to give you the benefit of the doubt (that is the mellow wisdom of advanced years for you) and assume that your question 'Are they young?' is to be answered in an ACBL context, where, despite being firmly on the downhill side of life, I am still many, many years below the median/average age of the membership! So, beware.. with my balding, greying, grizzled looks, I still count as 'young' somewhere!

 

I have, however, found another reason to bar my kibitizer (note the singular)... for which I, and my kibitzer, are indebted to you.

 

I'm not sure what to do about being at a seeded table... I think I'll just ask for an EW assignment... I'll claim it's for health reasons.. at my age I need to move around a lot, and, besides, most everyone else is far older and want to remain seated.

 

As for complicated cards, my experience is that young players with complicated cards are so devoted to weird science that they don't learn how to actually play or defend: I remember one of Fred's posts about such a pair who self-destructed to the tune of more than 100 imps in one match. Now, I suspect that it depends what's on their card: most mad young scientists play silly stuff... I should know, I was once one of them in my infancy.

 

OTOH, maybe foo is right after all... at my age the ability to think critically is waning fast.......

[foo]

Unless I am playing rank novices, I always assume an opponent is =capable= of falsecarding.

 

What I don't assume is that the chance of said falsecard is so high that I should automatically change my plans based on that possibility.

 

Probability, not possibility, should dictate the best plan for playing the hand unless some non mathematical factor weighs in. As Dorothy Truscott once said "all the math in the world is not worth an opponent's hitch telling you what they have."

 

So many players "grow up" these days without playing much money bridge that it seems the value of Table Feel and Partnership Management is not nearly as appreciated as it used to be.

 

IME, Table Feel matters more than math in deciphering what to do vs these potential mandatory Falsecard situations ATT.

 

Unfortunately, I do not seem to be making that point as clearly as I wish to.

[Stephen Tu]

Unless I am playing rank novices, I always assume an opponent is =capable= of falsecarding.

 

What I don't assume is that the chance of said falsecard is so high that I should automatically change my plans based on that possibility.

 

No, of course you shouldn't automatically change. You have to estimate the probability that an opponent is capable of falsecarding, and if he is capable, the frequency of which he will actually do so, and then compare to the alternative line. If you don't always assign probabilities to what card an opponent will choose when he has legitimate choice of plays, your analysis will be garbage.

 

The point of the matter is that stiff J is very rare, only 2.6% a priori. It's only 1.1% more frequent than you would expect the J to be played from JT doubleton (where the drop is superior).

 

On the other hand, JTx at 10.2% is quite common in comparison. Now, only an expert opponent is going to falsecard all the time, and only half the time he'll play the J. But 5.1 >>> 1.1. So against an expert it's clear to play for the drop. Now against a lesser player, maybe he'll remember to do so less than half the time, so maybe only 2% out of the original 10.2% he'll play the J. That *still* makes the drop better than the hook. Only against the people that have no clue that they are supposed to do this, so that the chance it's a falsecard is < 1.1/10.2, would the hook be better.

 

You are saying you shouldn't play for the drop since the possibility of a falsecard is low. But the possibility of stiff J is ALSO very low, and in fact the hook will be worse than the drop if you think your opponent is capable of playing the J even just 1/8 of the time he has that holding.

 

You can't make your points clearly because you are simply wrong. If you were right, you could identify the flaws in everyone else's logic better than we have with yours. Foo you'd be better off not trying to use math in your arguments, if you just argued that most people are idiots and would never falsecard your argument would be stronger. Once you start throwing out bogus numbers like "23% it's a falsecard" it undermines you.

 

Table Feel matters more than math

You seem to be contradicting yourself. First you say you should follow the numbers. Now you want to back table feel, since we've shown that your numbers are ridiculous.

 

Table feel can be quantified and treated mathematically to make a decision. You simply use table feel to adjust the probability you assign to the choice of plays. If your feel tells you your opponent is weak and would never falsecard, that the J is stiff, then you've just assigned 0% to the falsecard chance and you can justify taking the hook. But if you are playing against an expert, this would be a big mistake. Your prior claim was that the hook is better vs. all players and this is simply not true no matter how you analyze it.

[foo]

Let's try this again.

 

"All the math in the world is not worth an opponent's hitch telling you what they have."

 

IME, Table Feel matters more than math in deciphering what to do vs these potential mandatory Falsecard situations ATT.

 

IOW, I disagree with you that the math generates significant enough numbers that you should be assuming the opponents have Falsecarded unless you have additional evidence to support that hypothesis.

[matmat]

Play the odds. Not the opponents. Unless you are very confident of your table feel

xx

+

AKQ9xx

 

OW, I disagree with you that the math generates significant enough numbers that you should be assuming the opponents have Falsecarded unless you have additional evidence to support that hypothesis.

 

do you read what you write?

[foo]

Play the odds. Not the opponents. Unless you are very confident of your table feel

xx

+

AKQ9xx

 

OW, I disagree with you that the math generates significant enough numbers that you should be assuming the opponents have Falsecarded unless you have additional evidence to support that hypothesis.

 

do you read what you write?

Yep. Those advocating the play for drop against the expert but the play for split honors vs a non expert are basically saying that the expert is predictable enough that you should =trust an expert to always Falsecard=.

 

I've been saying all along that one should not trust an opponent to have Falsecarded without additional evidence to back it up.

 

The numbers involved are single digits of percentages that are very easily tipped in either direction.

 

I've been saying all along that Table Feel is a more reliable indicator of whether a Falsecard has taken place than just this math unless this math is backed by more confirmatory evidence.

 

 

As an aside, let's say random expert notices that all his opponents automatically play him to Falsecard 100% of the time when a Falsecard situation exists.

 

So he tweaks things so he plays a completely random card from the "mandatory falsecard" holding every time the the situation comes up.

 

Now when the card that hits the table is one that =could= be a Falsecard, the opponents can not so easily assume that the expert has Falsecarded. After all, sometimes he does and sometimes he doesn't...

 

Since this strategy rates to work more often than either never Falsecarding or always Falsecarding, it would seem clear that an expert's defense will indeed evolve in this direction.

[the hog]

Justin isn't this a restricted choice situation as well? I must admit I have never fully understood the rationale behind restricted choice, but if lho drops the J or T doesn't restricted choice suggest you should hook?

[Gerben42]

Yes in principle, but no because RHO may drop J or T from JTx as well to confuse you.

[Guest Jlall]

Justin isn't this a restricted choice situation as well? I must admit I have never fully understood the rationale behind restricted choice, but if lho drops the J or T doesn't restricted choice suggest you should hook?

The classic restricted choice holding is AKT9x opp xxxx. When you play the ace the queen drops behind you. The reason you should hook is that the possible options are

 

QJ tight

Q stiff

 

QJ tight is slightly more likely (since a specific 2-2 combo is more likely than a specific 3-1 combo), however the Q will be played from only half the QJ tights combos, so stiff Q is much more likely than half of the QJ tights.

 

In this case the possible options when the jack drops are:

 

J

JT

JTx(3)

 

Since there are 3 combos of JTx and one of JT, thats a total of 4 combos that playing for the drop wins against. However, as you noted, restricted choice applies, and the jack will only be played half the time from JTx and JT. Half of the 4 combos still leaves 2 combos. This is still (much) greater than the one combo that hooking wins against.

 

If you can rule JTx out because your opponent is not capable of dropping the jack from that holding you're again reduced to a situation analagous to my first example.

 

J

JT

 

The same restricted choie argument would now argue for a finesse.

[Guest Jlall]

Hi Stephen,

 

You can also look for other factors such as:

 

Are they young? (I would be inclined to think they could falsecard)

Do they have a kibitzer?

Are they at a seeded table?

Do they play complicated methods (I think this increases the chance that they know about mandatory falsecards, though obviously it's a generalization)?

If it is not the first board of the round, did they play competently on the other round?

Are they watching whats happening or just playing their card and turning it over quickly?

Are they foreign?

 

These things are not foolproof but are clues at least.

 

If it was day 2 of an NABC or higher I would assume they could falsecard.

As an old fogey who probably knew and used this falsecard before you were born, Justin, I'd like to get morally indignant!

 

But I am going to give you the benefit of the doubt (that is the mellow wisdom of advanced years for you) and assume that your question 'Are they young?' is to be answered in an ACBL context, where, despite being firmly on the downhill side of life, I am still many, many years below the median/average age of the membership! So, beware.. with my balding, greying, grizzled looks, I still count as 'young' somewhere!

 

I have, however, found another reason to bar my kibitizer (note the singular)... for which I, and my kibitzer, are indebted to you.

 

I'm not sure what to do about being at a seeded table... I think I'll just ask for an EW assignment... I'll claim it's for health reasons.. at my age I need to move around a lot, and, besides, most everyone else is far older and want to remain seated.

 

As for complicated cards, my experience is that young players with complicated cards are so devoted to weird science that they don't learn how to actually play or defend: I remember one of Fred's posts about such a pair who self-destructed to the tune of more than 100 imps in one match. Now, I suspect that it depends what's on their card: most mad young scientists play silly stuff... I should know, I was once one of them in my infancy.

 

OTOH, maybe foo is right after all... at my age the ability to think critically is waning fast.......

Mike, my point about old vs young is in the context of not knowing who the person is.

 

Generally if someone is old and good, they will be fairly known, at least locally. If someone is young and good they may not be known (yet). Also I generally think younger people who learn the game are more into the deceptive side than older people.

 

Your point about people who play complicated stuff often not knowing anything about cardplay is valid, but people who play uncomplicated stuff often just know nothing about anything. It is of course possible that people playing vanilla OR people playing a complicated system could know what they're doing, but I think there will be a higher correlation with the people who play complicated stuff being able to falsecard.

 

As far as sitting EW to avoid being seeded, too bad I will still know you are table 3 when you come sit down against me ;) I will also see your name on your card unless you have left it out for deceptive reasons ;)

[the hog]

Justin isn't this a restricted choice situation as well? I must admit I have never fully understood the rationale behind restricted choice, but if lho drops the J or T doesn't restricted choice suggest you should hook?

The classic restricted choice holding is AKT9x opp xxxx. When you play the ace the queen drops behind you. The reason you should hook is that the possible options are

 

QJ tight

Q stiff

 

QJ tight is slightly more likely (since a specific 2-2 combo is more likely than a specific 3-1 combo), however the Q will be played from only half the QJ tights combos, so stiff Q is much more likely than half of the QJ tights.

 

In this case the possible options when the jack drops are:

 

J

JT

JTx(3)

 

Since there are 3 combos of JTx and one of JT, thats a total of 4 combos that playing for the drop wins against. However, as you noted, restricted choice applies, and the jack will only be played half the time from JTx and JT. Half of the 4 combos still leaves 2 combos. This is still (much) greater than the one combo that hooking wins against.

 

If you can rule JTx out because your opponent is not capable of dropping the jack from that holding you're again reduced to a situation analagous to my first example.

 

J

JT

 

The same restricted choie argument would now argue for a finesse.

Thanks.