Crocodile or not

[paulg]

[hv=d=n&v=n&n=s8764hjdc&w=skt9xhdcx&e=s??hdxxxc&s=sa??ht6dc]399|300|Scoring: IMP

Hearts are trumps.[/hv]

 

South, declarer in a heart contract, needs four of the five tricks. The distribution is known to all players, so East knows West has four spades but not what they are.

 

South leads a spade from the North hand.

 

East plays a quack and South wins the trick with the ♠A. A low spade is led, what card do you play as West if

 

(i) East had played the ♠J

(ii) East had played the ♠Q

 

Paul

[ArtK78]

It depends on your agreements.

 

Partner has an automatic unblock with Qx or Jx. Unfortunately, he can't tell you whether he has Qx/Jx or QJ.

 

Many players play that with QJ you play Q. Many players play that with QJ you play J. I have gotten into some spirited discussions on this issue which usually wind up in my playing whatever my partner is happy with.

 

As long as you have an agreement, whether it is the right one (the one that I want to play) or the wrong one (the one that my partner wants to play), you will get this right at least 50% of the time.

[Halo]

Instinct says East plays:

 

QJ

Qx

Jx

 

Then West works it out.

[ArtK78]

Instinct says East plays:

 

QJ

Qx

Jx

 

Then West works it out.

If partner plays x from Jx you can never succeed on this layout.

[Halo]

Instinct says East plays:

 

QJ

Qx

Jx

 

Then West works it out.

If partner plays x from Jx you can never succeed on this layout.

Of course. I'll look forward to a better solution.

[jdonn]

The bottom line is you should never get this right if partner has QJ, since if he plays (say) the Q from that he must also play the Q from Qx, and since there are two Qx but only one QJ, QJ is what you have to pay off to. This applies even twice as much if you aren't sure which partner will play from QJ, since then restricted choice applies.

 

Of course with a weak partner the exact opposite applies, since if partner is too weak to play Q or J from Hx, then if he plays one he must have QJ.

 

This is a situation most people would get right at the table based on partner's tempo before playing the Q, sadly.

[ArtK78]

The bottom line is you should never get this right if partner has QJ, since if he plays (say) the Q from that he must also play the Q from Qx, and since there are two Qx but only one QJ, QJ is what you have to pay off to. This applies even twice as much if you aren't sure which partner will play from QJ, since then restricted choice applies.

 

Of course with a weak partner the exact opposite applies, since if partner is too weak to play Q or J from Hx, then if he plays one he must have QJ.

 

This is a situation most people would get right at the table based on partner's tempo before playing the Q, sadly.

Tempo issues aside, if you have an agreement as to which honor you play from QJ, you should get 1/2 of the Qx/Jx situations right all of the time and the other half of them right some of the time. In addition, you should get some of the QJ situations right some of the time.

 

The bidding and the play may give you an indication as to the likelihood of Qx/Jx or QJ in partner's hand.

[han]

Are you known to have the spade king? If not and partner played the jack then you might play the king arguing that declarer would have taken the finesse.

 

For the rest I agree with jdown.

[david_c]

Are you known to have the spade king? If not and partner played the jack then you might play the king arguing that declarer would have taken the finesse.

That was my first thought too, but I don't think it's right. If declarer knows East has only two spades (as we were told) then he won't finesse, because ace and another will work equally well if the finesse is right.

[han]

You are right of course.

[jdonn]

Tempo issues aside, if you have an agreement as to which honor you play from QJ, you should get 1/2 of the Qx/Jx situations right all of the time and the other half of them right some of the time. In addition, you should get some of the QJ situations right some of the time.

 

The bidding and the play may give you an indication as to the likelihood of Qx/Jx or QJ in partner's hand.

That is not right, because you are forgetting restricted choice among declarer's spot cards when partner has QJ. Say you have agreed to play Q from QJ. And say the missing spots are 3 and 2 (if you have KT95)

 

Partner holds:

QJ: He plays Q, declarer wins A and half the time plays 3 (1/6 overall), half the time plays 2 (1/6).

Q3: He plays Q, declarer wins A and plays 2 (1/3 overall).

Q2: He plays Q, declarer wins A and plays 3 (1/3 overall).

 

So when partner plays Q and declarer wins and plays 3, that is the 1/6 partner had QJ and declarer chose to exit with the 3, and the 1/3 the time partner had Q2, so it's 2/3 to play partner for Q2. Similarly when partner plays Q and declarer plays 2 it is 2/3 to play partner for Q3.

 

Of course as you say, when partner plays the J in this scenario you know he has J3 or J2. So as I said the first time (although not quite for the reason I said so), you should never play partner for QJ here.

 

If you have no agreement of which to play from QJ, then it becomes more complicated but still you should never play partner for QJ.

[MickyB]

Seems right to play the J from QJ...it's more likely that partner can count you for a queen than for a jack.

[ArtK78]

The rationale for playing partner for the Jx/Qx as opposed to QJ does not come from the spot cards played. It comes from clues that you have obtained from the bidding and from the play.

 

If you cannot figure out whether partner has Jx/Qx as opposed to QJ from the bidding and play to that point, then you are left with any other analysis that you choose to make. Your restricted choice argument (which, quite frankly, I find to be strained) leads to the conclusion that it is less likely that partner has QJ than that he has Qx/Jx. If that is the entire point of your argument, fine - I accept that.

 

The other issue is whether you know if declarer can work out from the play to that point that your partner holds a doubleton spade. If that is not known, why would he be eschewing the spade finesse with a hypothetical original holding of AQx? Of course, if your partner played the ♠Q on the first round of the suit, then declarer's holding is no better than AJx, so you know why he didn't finesse. But if partner played the ♠J on the first round of the suit, then we go back to the original question - does declarer know enough about the hand to know that it is wrong to simply take the spade finesse if his spade holding is AQx?

 

It is far more likely that you will be able to determine partner's spade holding by trying to figure out if declarer's hand is consistent with the bidding and the play to that point than through any other analysis.

[MFA]

I think the logic is to play

J from QJ

(Q from Qx)

(J from Jx).

 

This solves the 'standard' situation (with obscure spade distribution for declarer), in which the defenders can rely on declarer taking the finess at some point with AQx.

 

In this situation, declarer doesn't have to take a finess, obviously, because he knows that east has a doubleton.

But the defenders should defend the same way regardsless.

 

There is simply no technical advantage whatsoever to shifting defensive strategy when we know that declarer knows the distribution. We are just running the risk that partner has gauged declarer's information differently and plays J from QJ for technical reasons (the AQx-finess argument).

 

So we'll stick to it, and if partner drops the J, we'll have a judgement call to make, nothing to do about that.

[jdonn]

The rationale for playing partner for the Jx/Qx as opposed to QJ does not come from the spot cards played.  It comes from clues that you have obtained from the bidding and from the play.

 

If you cannot figure out whether partner has Jx/Qx as opposed to QJ from the bidding and play to that point, then you are left with any other analysis that you choose to make.  Your restricted choice argument (which, quite frankly, I find to be strained) leads to the conclusion that it is less likely that partner has QJ than that he has Qx/Jx.  If that is the entire point of your argument, fine - I accept that.

 

The other issue is whether you know if declarer can work out from the play to that point that your partner holds a doubleton spade.  If that is not known, why would he be eschewing the spade finesse with a hypothetical original holding of AQx?  Of course, if your partner played the ♠Q on the first round of the suit, then declarer's holding is no better than AJx, so you know why he didn't finesse.  But if partner played the ♠J on the first round of the suit, then we go back to the original question - does declarer know enough about the hand to know that it is wrong to simply take the spade finesse if his spade holding is AQx?

 

It is far more likely that you will be able to determine partner's spade holding by trying to figure out if declarer's hand is consistent with the bidding and the play to that point than through any other analysis.

Obviously if you can figure out through the bidding or a play inference that partner has the spade queen, then when partner plays the jack you will play him for the queen next round etc. etc. etc.. which is, I'm sorry, entirely pointless. The poster asks what you play partner for you and your answer is "I figure it out from the bidding and play"? That does nothing to solve the true problem he is wondering, which is how you should know whether partner has Qx, Jx, or QJ based on partner playing the Q or the J. Obviously if the idea is to figure it out from the bidding and play, we would have been given the bidding and play, not given a problem to solve in a vacuum.

 

I also have no idea what you mean when you say my argument is strained, unless strained is synonomous with "100% true and easily proven", which I did. There is no reason to be in denial just because you didn't think of an aspect of the situation and thus got led to an inaccurate answer.

 

Anyway you do accept that it's always less likely partner has QJ. Meaning you should never play for that, rendering anything else moot (short of, of course, the bidding and play, with which this problem doesn't exist.)

[ArtK78]

With all due respect, jdonn, that has got to be one of the silliest "serious" posts I have ever seen.

 

Why don't you just say "I am right and you are wrong."? You spent a lot of time saying essentially that.

 

The idea that your argument proved that your position is "100% true and easily proven" is preposterous.

[jdonn]

Why don't you just say "I am right and you are wrong."? You spent a lot of time saying essentially that.

You're right, "I refuse to admit you are right because it proves I was wrong" is much less silly of a position.

[CSGibson]

I say go for the Croc if partner plays the jack, but not the queen. Queen looks like an unblock, jack looks like the right play from that combo if partner knows he needs a croc becuase he can give p the additional "Why didn't declarer finesse" thought, especially if the distribution is unknown.

 

Plus it's a way better story to tell if the Croc is right and you guess it.

 

Incidentally, I got my first Croc last friday, but partner was playing from a jack-ten combo, which was easier to visualize, as there was less reason for p to unblock the ten, and no reason for declarer to eschew the finnesse.

[paulg]

I say go for the Croc if partner plays the jack, but not the queen.  Queen looks like an unblock, jack looks like the right play from that combo if partner knows he needs a croc becuase he can give p the additional "Why didn't declarer finesse" thought, especially if the distribution is unknown.

 

Plus it's a way better story to tell if the Croc is right and you guess it. 

 

Incidentally, I got my first Croc last friday, but partner was playing from a jack-ten combo, which was easier to visualize, as there was less reason for p to unblock the ten, and no reason for declarer to eschew the finesse.

This is my view.

 

And croc's are always a good story however easy they might appear to be !

 

Paul

[Finch]

The bottom line is you should never get this right if partner has QJ, since if he plays (say) the Q from that he must also play the Q from Qx, and since there are two Qx but only one QJ, QJ is what you have to pay off to. This applies even twice as much if you aren't sure which partner will play from QJ, since then restricted choice applies.

 

Of course with a weak partner the exact opposite applies, since if partner is too weak to play Q or J from Hx, then if he plays one he must have QJ.

 

This is a situation most people would get right at the table based on partner's tempo before playing the Q, sadly.

This looks entirely correct to me.

[benlessard]

Agree here too.

 

In standard when you play after dummy & before partner and you want to split (insert) you should play the higher of touching honnors. The rationale behind this is that to deny an honnor is more important then to show an honnor.

 

 

 

inserting the J= denies the Q may or may not have the T.

Inserting the Q= Denies the K may or may not have the J.

 

 

If you play the otherway around.

(playing the J from QJ)

 

J= denies the T may or may not have the Q.

Q= denies the J may or may not have the K.

 

most of the time method 1 is superior.

 

So if partner put the J = i always win.

 

If partner play the Q = Qx or QJ. Qx is more likely.

[dburn]

I haven't read the answers to this particularly closely; apologies for any old ground I may be covering. jdonn appeared to me to be writing sense, ArtK78 to be writing nonsense, but rather than look at their arguments in detail I thought I would offer my own explanation.

 

Since East must play an honour if the defence is to have any chance of beating the contract, nothing can be inferred about his holding when he does - in particular, no agreement as to whether one plays the queen or the jack from QJ doubleton can avail. West should simply defend as if his partner had Hx, since he will have this considerably more often than he will have QJ. Restricted choice is not an issue here; nobody has any choice (unless you wish to argue that one can always choose to misdefend).

[MFA]

jdonn:

The bottom line is you should never get this right if partner has QJ, since if he plays (say) the Q from that...

benlessard:

In standard when you play after dummy & before partner and you want to split (insert) you should play the higher of touching honnors.

...

If partner play the Q = Qx or QJ. Qx is more likely.

dburn:

Since East must play an honour if the defence is to have any chance of beating the contract, nothing can be inferred about his holding when he does - in particular, no agreement as to whether one plays the queen or the jack from QJ doubleton can avail.

 

I think you are overlooking that this is not a matter of agreements!

East must play J from QJ for technical reasons in these crocodile situations.

 

The jack from QJ gives partner one more (free!) clue to get it right and rise with the K: with AQx declarer might have finessed.

This clue is weak, when declarer is supposed to know the whole distribution (still he might not), and strong when he is acting "in vacuum".

But it IS a clue!

 

So, when partner plays the Q, he has Qx

When he plays the J, we have a problem.

 

jdonn:

The bottom line is you should never get this right if partner has QJ...

 

Never is a strong word. Odds are 2:1 to play for Jx, but we do still have the bidding and 8 tricks of cardplay to judge differently.

[ArtK78]

As was pointed out to me by a prominent poster on this thread in private e-mail correspondence, I missed an important point in the analysis of this problem. And MFA, while noting that this point exists, seems to base at least part of his analysis without taking the point into consideration.

 

The distribution of all four hands is known to the declarer and to the defenders.

 

Since RHO is known to hold a doubleton, declarer should not consider finessing the Q with an original holding of AQx. By playing A and then low, if the K is onside it will fall on air.

 

Playing A and then low also has the advantage of creating a nearly impossible problem for the defense to solve regarding the blocking of the suit.

 

As the problem states that declarer knows that RHO has a doubleton, he should also be able to make the play of A and another. So the clue that declarer might have finessed the Q if he held AQx is not a clue at all.

 

Hopefully, this will conclude this discussion. I have contributed to the confusion on this issue as much as anyone.

[MFA]

As was pointed out to me by a prominent poster on this thread in private e-mail correspondence, I missed an important point in the analysis of this problem.  And MFA, while noting that this point exists, seems to base at least part of his analysis without taking the point into consideration.

 

The distribution of all four hands is known to the declarer and to the defenders.

I did most certainly take this into consideration.

 

...

This clue is weak, when declarer is supposed to know the whole distribution (still he might not), and strong when he is acting "in vacuum".

But it IS a clue!

 

See?

Just because we know that declarer ought to have full count, doesn't mean that he always has.

 

People are known to miss some points from time to time :rolleyes:.