[benlessard]

Ive done 2 falsecards lately while most of the time I completly miss them. The first one is classic but declarer shouldnt fall for it.

AKTx
Q8x


you have J9x as west. Declarer led low from hand and you put up the J so that he might finesse against the 9 if he think your J is stiff (it shouldnt work but its a freeroll).


The 2nd one im far from sure.

A7xxx
-----------Tx
J98 (he had the holding I was hoping for)

should East play the T from Tx. Because of the bidding partner was marked with K or Q (declarer POV) and possibly both (my POV).

[Stephen Tu]

I don't understand your thinking on the first one. If you put up the J, declarer has 4 top winners, why would he ever hook on the way back? It's also not free if declarer has xxxxx although they probably get it right through restricted choice, but maybe they don't have enough entries for that? Do you have this confused with the falsecard of the 9 from J9xx where declarer has Q8xx?

On the second one, the T is the right play if declarer is intra-finessing. But if they have KJ9, and partner is marked with Q, you take away their guess 2nd round of playing partner for Qx or Qxx?

[rduran1216]

Last night trumps on the board were J9x, I held Q10 tight.

So on the lead of the A, I played the Q, then scored the 10 on the next round, it was sexy.

[phil_20686]

 Stephen Tu, on 2012-August-01, 09:59, said:

I don't understand your thinking on the first one. If you put up the J, declarer has 4 top winners, why would he ever hook on the way back? It's also not free if declarer has xxxxx although they probably get it right through restricted choice, but maybe they don't have enough entries for that? Do you have this confused with the falsecard of the 9 from J9xx where declarer has Q8xx?

On the second one, the T is the right play if declarer is intra-finessing. But if they have KJ9, and partner is marked with Q, you take away their guess 2nd round of playing partner for Qx or Qxx?

I presume he means if he inserts the 9, rather than the J, then you have the chance to finesse against the J in either direction for four tricks, assuming you don't just play for the drop.

[Phil]

As Stephen says on the 1st example, the J gives four tricks, so I fail to see why this is a 'freeroll'. It's far from a freeroll if partner has Qx!

The 2nd example is described in Rodwell's book as an 'intrapop'. The idea is you are feigning K-T or Q-T and trying to get declarer to not finesse partner out of his presumed KQx.

 rduran1216, on 2012-August-01, 10:30, said:

Last night trumps on the board were J9x, I held Q10 tight.

So on the lead of the A, I played the Q, then scored the 10 on the next round, it was sexy.

yawn

[benlessard]

Your right the first one cannot work (the 9 might but shouldnt work however) I dont know what I was thinking I nkew declarer didnt have 4 so its was safe but totally useless.

The 2nd one is not clear to me
since im not sure what east should do with KT,QT (I think playing the T is better with both holding).

[Phil]

 benlessard, on 2012-August-01, 11:02, said:

The 2nd one is not clear to me
since im not sure what east should do with KT,QT (I think playing the T is better with both holding).

Right. If you rise honor, can play you for the RC choice of KT/QT vs KQ tight. With the T, declarer has to figure out stiff T (or the intrapop of T-x) or H-T.

With a bad player I will play for KQ because they will never play the T from QT / KT.

I'll let the math kids figure out how often you are supposed to play the T from T-x.

[ArtK78]

 rduran1216, on 2012-August-01, 10:30, said:

Last night trumps on the board were J9x, I held Q10 tight.

So on the lead of the A, I played the Q, then scored the 10 on the next round, it was sexy.

Did this once when trump on the board were Ax and declarer was marked with 6 trump.

It almost has to work against a decent declarer if partner does not have the 9 (and maybe even if he does).

[JLOGIC]

 Phil, on 2012-August-01, 11:19, said:

I'll let the math kids figure out how often you are supposed to play the T from T-x.

lol, 100 % of the time assuming declarer is going to intra finesse (which is likely when he starts with low towards the J98 with this holding, it is possible he needs only 3 tricks from the suit and would safety play though, in which case playing the ten might give up an overtrick).

It is a mandatory falsecard since when it goes low to the 8 and honor, declarers only play for 4 tricks now will be to run the jack. If you play the ten first he will have the option of playing you for HT doubleton. Another way to look at it is you are playing the card you will be about to be known to have.


Likewise, playing the 9 from J9x with Q8x in dummy is a mandatory falsecard when they have AKTx or AKTxx. True, it will not often work, but it meets the definition of a mandatory falsecard because if you don't play it, they have no losing options, if you play it they have the losing option of finessing the next time playing you for stiff 9.

By definition you should make mandatory falsecards 100 % of the time, hence why they are called mandatory.

[JLOGIC]

 JLOGIC, on 2012-August-01, 15:32, said:

lol, 100 % of the time assuming declarer is going to intra finesse.

It is a mandatory falsecard since when it goes low to the 8 and honor, declarers only play for 4 tricks now will be to run the jack.

By definition you should make mandatory falsecards 100 % of the time, hence why they are called mandatory.

Quoted to LOL myself, of course if it goes low to the 9 and honor, declarer could play for KQ doubleton and Txx, so I am stupid in calling this a mandatory falsecard. In practice 100 % is about right since everyone who starts low to the 9 and H will intra finesse, but if you played the T 100 % of the time from Tx and they knew that they should NOT intra finesse, so phil was absolutely correct with his question, lol @ me.

My post was correct in the unlikely event that declarer had a full count on the suit, in that case playing the T from Tx would in fact be a mandatory falsecard.

[gnasher]

It's when you have H10 that a mixed strategy applies. Not a very complex one though: you should play the 10 half the time. That gives declarer a 50-50 guess when you play the 10, and a 50-50 guess when you play an honour.

Edit: I made the same mistake as Justin. The above applies only if he is going to play for the suit to be 3=2.

This post has been edited by gnasher: 2012-August-01, 15:50

[JLOGIC]

 Phil, on 2012-August-01, 11:19, said:

I'll let the math kids figure out how often you are supposed to play the T from T-x.

All of this analysis assumes declarer needs 4 tricks in the suit, and everyone knows it

So, let's say the Tx player is known to have 2. Now he should play the T from Tx 100 % of the time. This meas declarers optimal solution would be to always pick up Tx, and also pick up KQ doubleton with you. That's right, if you play an honor he should play for KQ doubleton IF YOU ARE KNOWN TO HAVE A DOUBLETON. This is very similar to my post on KQT9xx opp xx where if it goes low to the king and ace you should play low to the queen.

This will make your play from HT doubleton irrelevant. This is only true because you are forced to play the ten from Tx in this situation, and obviously Tx is as likely as HT (both 2 combos). This is a highly artificial sitution, but cool theoretically anyways.

Let's say declarer knows the suit is 3-2, but you might have 2 or 3. Now the relevant holdings are

HT (2 combos)
Tx (2 combos)
Txx (1 combo)
KQ (1 combo)

To be perfectly balanced, we might want to start by saying with Tx we have to play low 1/2 the time to protect Txx (also remember to be randomizing your spot with Txx).

Likewise, with HT we want to play the honor half the time to protect our KQ.

Now we can play the ten the other half of the time we hold Tx and HT.

So in this way, if we play an honor, it is 50 % to be from HT, and 50 % to be KQ doubleton. If we play the ten, it is 50 % to be HT, and 50 % to be Tx. If we play low, it is 50 % to be Txx and 50 % to be Tx. Effectively, we are unexploitable.


It gets even trickier if the suit might be 4-1, as now you have to factor in stiff T.

[JLOGIC]

How about this strategy as declarer when the suit might be 4-1:

I will pick up stiff T and Tx, as well as KQ doubleton, no matter what you do. That is 4 combos (1 being a 4-1), and the opponents play becomes irrelevant from both Tx and HT. I think any other plan can be exploited by the opponents if they knew it? Is this correct?

That implies once again that if they pop with an honor, we should play for KQ doubleton. Their play from HT becomes irrelevant (both the H and T winning plays for them), as well as from Tx (both low and the ten lose for them). Can anyone come up with a better strategy?

[rduran1216]

 Phil, on 2012-August-01, 10:40, said:

As Stephen says on the 1st example, the J gives four tricks, so I fail to see why this is a 'freeroll'. It's far from a freeroll if partner has Qx!

The 2nd example is described in Rodwell's book as an 'intrapop'. The idea is you are feigning K-T or Q-T and trying to get declarer to not finesse partner out of his presumed KQx.



yawn

there is no yawn phil, it was delicious!

[Zelandakh]

I think it would be a nice idea to create a thread, perhaps (stickied) in I/A, listing all of the mandatory falsecards. If that is too easy then we could also add semi-mandatory ones and randomising positions. Do you think that might be feasible Justin?

[JLOGIC]

I am not sure I could do it, but I will offer that these are the 3 true mandatory falsecards that I know off the top of my head because they come up a lot, I would think others are less common or would basically not change anything ever (like the 9 from J9x in this example):


1) Any combo like:

AJ8xx in dummy, and you have T9x behind, and they lead low to the jack. You must play the T or the 9 in case they have Qxx, so that they ca try pinning T9 doubleton. If you don't play the ten or 9, the only possible play for 5 tricks is Kx onside.

2) When they have something like AK8x opp QTxx and play the ace, you must play the 9 from J9xx to give them the option of playing for stiff 9 and leading the queen next. If you don't play the 9, their only possible way to pick up 4-1 is J9xx in front of the QT so they will play the king.

3) If they have something like J9x opp AQxxx, or J9x opp AKxxx, and you have either KT or QT on, when they lead low towards the AQ or AK you must play your honor. Now they can choose to play you for stiff H and play low to the 9 next.

Those are the main 3 that come up a lot that are actually mandatory in the sense that they give declarer a losing option and if you don't do it they will not have a losing option. Knowing those off the top of your head are important, the otherss are probably less important.

There are many more that are not strictly mandatory but are basically always good plays. Maybe a falsecarding thread in general or a more broad semi-randomization thread like you suggested would be more useful. There are definitely many more mandatory ones though, just letting everyone contribute would be useful. Many are extensions of the principles in 1/2/3, eg if declarer has AQ9xxxxx opp void, and cashes the ace, you must play the J or T from JTx, same *****.

[JLOGIC]

 rduran1216, on 2012-August-02, 00:44, said:

there is no yawn phil, it was delicious!

Yes, I find it extremely interesting that the optimal strategy for 4 tricks with A7xxx opp J98 is to pay low towards dummy, and if they play an honor to play for KQ doubleton. In real life we would almost always play for HT doubleton, though that is not necessarily wrong in real life.

[FrancesHinden]

 JLOGIC, on 2012-August-02, 03:40, said:

I am not sure I could do it, but I will offer that these are the 3 true mandatory falsecards that I know off the top of my head because they come up a lot, I would think others are less common or would basically not change anything ever (like the 9 from J9x in this example):


1)
2)
3)

4)
dummy has AJx, declarer has K9xx, you are sitting under dummy with Q10x. Declarer plays low to the jack and cashes the ace, you must play the queen.

(does this fail because it's not exactly a 'false' card in that your two remaning cards are equals?)

[MrAce]

 FrancesHinden, on 2012-August-03, 01:59, said:

4)
dummy has AJx, declarer has K9xx, you are sitting under dummy with Q10x. Declarer plays low to the jack and cashes the ace, you must play the queen.

(does this fail because it's not exactly a 'false' card in that your two remaning cards are equals?)

It is of course false carding but it also fits into "playing the card you are known to hold" category.

But yes, regardless of what we choose to call it, it is mendatory of course. (unless pd shows up on 2nd round )