Falsecards and Restricted Choice
st...@flash.net
Larry Cohen has an article in the Feb 98 ACBL Bulletin (p. 102)
on the Politiken World Pairs in Copenhagen during Nov. 97.
He gives this hand as the most interesting of this strong 16 pair
event (IMP scoring - money prizes for the top 7 pairs).
None vul.
K3
J32
Q987
QT97
9 AJ85
K65 AQ874
AKJT2 4
AK43 J52
QT7642
T9
653
86
Of the eight tables, 3 EW played in 6H, the other 5 in 7H.
To quote Cohen: "All five declarers in the grand slam went down,
however. They reasonably chose to play for 4-3 diamonds and no
worse than 6-2 spades (sic). They won a trump opening lead with
dummy's king and played the SA, spade ruff, DA, diamond ruff,
spade ruff and - oops! - they were overruffed. Maybe the
fall of the SK should have gotten them to change their minds,
but it easily could have been from SKQ3 or a falsecard from
SKQ63 or the like."
Cohen previously pointed out that taking the ruffing finesse in
diamonds would produce 13 tricks.
What bothers me is why no one played that line after seeing the
SK on the second spade. The rule of restricted choice makes
it twice as likely to be from K3 rather than KQ3 if it is a true
card. Granted the majority of these world class defenders would be
up to the false card; but doesn't the rule of restricted choice
also apply here. If you are falsecarding from KQ63, aren't you
going to play the K half the time and the Q the other half??
After all the falsecard objective is to make it look like you
have a doubleton?
So if declarer expects a falsecard when adjacent honors are missing
it is 2:1 that the card is a true card and not a false card.
Does it come down to: play for the card to be true?
Even at world-class play, can you afford to pay off to the
falsecard? Or does one's ego come into action here:
declarer would never allow himself to be duped by a fellow expert?
-Stu Goodgold
-----== Posted via Deja News, The Leader in Internet Discussion ==-----
http://www.dejanews.com/ Now offering spam-free web-based newsreading
David Ackerley
Possibly true - but not really relevant here. This is far from being a
restricted choice situation - there is absolutely nothing to stop North
from ditching their KS from Kxx or even Kxxx - in fact, it would be a
perfectly standard falsecard, hardly requiring a world class player to
make it. In principle, this is similar to the situation with AQ9xxx
opposite Kx - if you cash the king and the ten or jack fall on your right
restricted choice would suggest that you hook the 9, but given that there
is nothing to prevent your RHO dropping an honour from JTx you would be a
bit of a mug to do so unless you had reason to suspect that they were
short in the suit. There are SOME falsecards that you should never pay
off to.
Sue Picus/Barry Rigal
falsecards in highclass fields is a timely theme.
consider yourself to be a world class player in the Cap Gemini.
you have a trump suit of Q876 (dummy)
AK105 in hand
You lead to the king; it goes 2K9.you are playing a slam and must play
the suit for no losers.
What do you do next?
what would you do if you were playing against the two women pairs in the
field? (contributors are being given a chance to display their
chauvinism!).
Barry Rigal
Richard Haydon
What's this? A Grosvenor in the Cap Gemini?
Sue Picus/Barry Rigal <sue-...@worldnet.att.net> wrote in article
<6djj27$n...@bgtnsc03.worldnet.att.net>...
> you have a trump suit of Q876 (dummy)
>
> AK105 in hand
>
> You lead to the king; it goes 2K9.you are playing a slam and must play
> the suit for no losers.
>
> What do you do next?
Like everyone else, I play the 5 to the Q and congratulate LHO on her sense
of humour if she's played the 9 from J9xx
Richard
B. K. Oxley (binkley)
Sue Picus/Barry Rigal wrote in message
<6djj27$n...@bgtnsc03.worldnet.att.net>...
>falsecards in highclass fields is a timely theme.
>
>consider yourself to be a world class player in the Cap Gemini.
>
>
> AK105 in hand
>
>You lead to the king; it goes 2K9.you are playing a slam and must play
>the suit for no losers.
>
>What do you do next?
Ignoring the silly question about the women players, I'll lead low from
hand, and if nothing interesting happens, finesse the 8.
Given that the 2, 3 and 4 are out, and that these opponents are most
unlikely to give any sort of accurate count in trump (especially since you
present this as a single-suit problem), the 9 is more likely from J9 or J943
than from 943, 94 or 93. But I'll pay off if it is.
RHO having played the 2, he is unlikely to have the 3 by Restricted Choice.
What I have to worry about most is a clever LHO playing the 9 without the J
in an attempt to get me to finesse her.
This position is vastly easier against trustworthy, weak opponents!
--binkley
Bill Daly
Sue Picus/Barry Rigal wrote in message
<6djj27$n...@bgtnsc03.worldnet.att.net>...
>falsecards in highclass fields is a timely theme.
>
>consider yourself to be a world class player in the Cap Gemini.
>
>you have a trump suit of Q876 (dummy)
>
> AK105 in hand
>
>You lead to the king; it goes 2K9.you are playing a slam and must play
>the suit for no losers.
>
>What do you do next?
>
>what would you do if you were playing against the two women pairs in the
>field? (contributors are being given a chance to display their
>chauvinism!).
>
>Barry Rigal
Did you mean this to be a Grosvenor coup situation? Surely LHO would not
play the 9 from J9xx here.
A more interesting question is when it goes 6-9-K-2. Now RHO might well have
J9xx, and it is a standard "obligatory" falsecard to play the 9 from this
holding, as otherwise declarer can't go wrong. On the other hand, if you
play the 9, an expert declarer will reason that there are 3 holdings from
which you would play the 9 with J9xx and only 1 holding with a singleton 9,
so he shouldn't go wrong anyway. RHO needs to play the 9 from J9xx about 25%
of the time to protect those hands when he is dealt the singleton 9. On the
other hand, there are occasions when it can be disastrous to play the 9 from
J9xx, e.g. when partner has the singleton T, and even when declarer has AKT,
if he thinks that when you play the 9, there is a 75% chance that you have
J9xx, he may well pick up a suit that he would otherwise never guess.
In an expert field, it is surely right to play small to the Q next, since
almost all experts will always play the 9 from J9xx, even if they shouldn't.
Regards,
Bill
Richard Pavlicek
Sue Picus/Barry Rigal wrote:
> you have a trump suit of Q876 (dummy)
> AK105 in hand
>
> You lead to the king; it goes 2K9.you are playing a slam and must play
> the suit for no losers.
>
> What do you do next?
In your play sequence a falsecard is inane, so low to the
queen is automatic. Perhaps, you meant "9K2" in which case
I'd believe the 9 and cash the ace. RHO would be unlikely to
falsecard with J9xx for fear of a stiff 10.
--
Richard
Web site: http://www.gate.net/~pavlicek
Giuseppe Bianchi
Sue Picus/Barry Rigal <sue-...@worldnet.att.net> wrote:
>you have a trump suit of Q876 (dummy)
> AK105 in hand
>
>You lead to the king; it goes 2K9.you are playing a slam and must play
>the suit for no losers.
You mean 9 on your right (6 - 9 - K - 2).
>what would you do if you were playing against the two women pairs in the
>field? (contributors are being given a chance to display their
>chauvinism!).
Did the women that played the 9 have a Kibitzer?? (reference to
Zia's book :-))
Giuseppe.
PS: I play in both cases for Jxxx on my left, as this falsecard is
definitely NON mandatory in this situation (i.e. the 9 dropper seeing
only Q876 in dummy). The reason is explained with this brief story (free
inspiration from a beatiful and much longer article that appeared in an
old italian bulletin: whenever I go back to Italy, I try to find it
and translate it on rgb).
A strong player was out of town. He went to a local club in the visited
city, and, presenting himself as a good player, he picked up a decent
partner. At the first hand, they ended up defending 6S after declared
had opened the bidding with 1NT.
dummy: Q876 (dummy)
strong visitor: J954
Declarer played the 6 from dummy. The 9 came on the table, declarer
played the A and partner dumped the TEN! Declarer then, a little bit
dazed, but not much (he didn't know the visitor), played small to the
Q, LHO showing out, and finessed the J of spades for an incredible 6S
making top board. An old kibitzers, and local "authority", disgusted,
said in low voice to the partner of the visitor: "It will be a very
looong night for you! This visitor is an utter beginner! 6S cannot make,
never. He had *just* to follow suit.... Yes, we never have to trust people
that present themselves as "good" players!
--
Giuseppe Bianchi
bia...@comet.columbia.edu
bia...@elet.polimi.it
Larry Risch
First I think 2K9 means
6
2 9
K
and it seems very clear to me that way, rather than the order the
cards are played, but no matter.
I would not worry about the stiff 10 since south is at least two times more
likely
to hold that card. AKxx vs x or AKxxx vs void, IF that the false card will
paid off
more often than hoping partner has the stiff 10.
Now if all experts would false card in this situation, than no expert
declarer would
fall for it! But then soon no expert defender would false card in this
situation if it did not pay off, but then declares would then adjust their
play as well etc.,This can get quite circular.
SO, lets say we false card 1/3 the time with this holding. Now the 9 would
appear
equally as often as a false card and as a singleton, so we would have a
pure guess.
Of course from defender's viewpoint, the 1/3 of the time I do this false,
half should
pay off the 2/3 of the time partner does not have the stiff 10, and lose
when partner
has the stiff 10 1/3 of the time. But I also gain on those times
when I DO have the stiff nine and declarer's miss guesses on those hands.
So false carding some of the time seems better.
Sue Picus/Barry Rigal <sue-...@worldnet.att.net> wrote in article
<6djj27$n...@bgtnsc03.worldnet.att.net>...
> falsecards in highclass fields is a timely theme.
>
> consider yourself to be a world class player in the Cap Gemini.
>
> you have a trump suit of Q876 (dummy)
>
> AK105 in hand
>
> You lead to the king; it goes 2K9.you are playing a slam and must play
> the suit for no losers.
>
> What do you do next?
>
> what would you do if you were playing against the two women pairs in the
> field? (contributors are being given a chance to display their
> chauvinism!).
>
> Barry Rigal
>
dgo...@bright.net
Of course, if the 9 is from J943, playing the 9 on the first round risks
sacrificing a natural trump trick.
(There's a name for that coup, but I don't recall it)
If you finesse the 8, picking up J943, you will win this time, but LHO
will own you for life.
Small to the Queen.
Don
B. K. Oxley (binkley) wrote:
> >consider yourself to be a world class player in the Cap Gemini.
> >
> >you have a trump suit of Q876 (dummy)
> >
> > AK105 in hand
> >
> >You lead to the king; it goes 2K9.you are playing a slam and must play
> >the suit for no losers.
> >
> >What do you do next?
>
st...@flash.net
In article <Pine.OSF.3.91.980304...@sanger.otago.ac.nz>,
David Ackerley <da...@sanger.otago.ac.nz> wrote:
>
> Possibly true - but not really relevant here. This is far from being a
> restricted choice situation - there is absolutely nothing to stop North
> from ditching their KS from Kxx or even Kxxx - in fact, it would be a
> perfectly standard falsecard, hardly requiring a world class player to
> make it. In principle, this is similar to the situation with AQ9xxx
> opposite Kx - if you cash the king and the ten or jack fall on your right
> restricted choice would suggest that you hook the 9, but given that there
> is nothing to prevent your RHO dropping an honour from JTx you would be a
> bit of a mug to do so unless you had reason to suspect that they were
> short in the suit. There are SOME falsecards that you should never pay
> off to.
>
there is a 33% chance that he holds the other honor (restricted
choice), even given that he will falsecard 100% of the time
with JTx.
So hooking the 9 will win 67% of the time.
However, the 3-2 split will occur apriori 71% (given no 5-0 split),
so playing for the drop is still indicated here.
If your RHO is a novice, OTOH, he must have stiff honor or JT tight.
It's 2:1 in favor of the stiff, so the finesse is better.
(67% of the time, LHO will hold Hxxx).
Steve Grant
Sue Picus/Barry Rigal wrote:
>
> falsecards in highclass fields is a timely theme.
>
>
> you have a trump suit of Q876 (dummy)
>
> AK105 in hand
>
> You lead to the king; it goes 2K9.you are playing a slam and must play
> the suit for no losers.
>
> What do you do next?
>
> field? (contributors are being given a chance to display their
> chauvinism!).
>
> Barry Rigal
Do you believe LHO is capable of falsecarding the 9 from J9xx as often
as one time in 3? Hard to believe she could have been invited to the
Cap Gemini otherwise. So continue with the other high trump from hand.
Or you could just say, "If trumps are 3-2, I'm solid." When nobody
makes a move, you can write editorials in the Bridge World on the
subject for years and years to come :)
Maybe the best play was to come to hand in a side suit and *cash* a high
honor from hand. Especially if you didn't have the ten....
Steve
Thomas Andrews
In article <6dks0e$bl8$1...@nnrp1.dejanews.com>, <st...@flash.net> wrote:
>In article <Pine.OSF.3.91.980304...@sanger.otago.ac.nz>,
> David Ackerley <da...@sanger.otago.ac.nz> wrote:
>>
>> Possibly true - but not really relevant here. This is far from being a
>> restricted choice situation - there is absolutely nothing to stop North
>> from ditching their KS from Kxx or even Kxxx - in fact, it would be a
>> perfectly standard falsecard, hardly requiring a world class player to
>> make it. In principle, this is similar to the situation with AQ9xxx
>> opposite Kx - if you cash the king and the ten or jack fall on your right
>> restricted choice would suggest that you hook the 9, but given that there
>> is nothing to prevent your RHO dropping an honour from JTx you would be a
>> bit of a mug to do so unless you had reason to suspect that they were
>> short in the suit. There are SOME falsecards that you should never pay
>> off to.
>>
> When RHO plays J or T on the first trick in your situation,
>there is a 33% chance that he holds the other honor (restricted
>choice), even given that he will falsecard 100% of the time
>with JTx.
I think you are confused here.
Restricted choice is very specific, and can get thrown for a loop
if too casually applied.
The mathematics of this are not hard to fathom.
Let's say you are declarer, Kx in hand and AQ9xxx in dummy.
When you play the king, RHO plays the J.
Under what circumstances will RHO play the J?
A) Every time he holds the stiff jack he plays the jack.
B) Half the time when he holds JT he plays the jack.
C) Some of the time when he holds JTx he plays the jack.
D) Some of the time when he holds Jx or Tx.
In case (A), finessing wins and the drop loses.
In case (D), finessing *and* playing for the drop win.
In case (B) and (C) the drop wins, finessing loses.
So the question is, which is more more likely (A), or (B or C).
That partly depends on RHO. A good RHO will realize that playing
one of the J or the T from JTx is a *mandatory* false-card.
There is no way for you to go wrong in this situation if
RHO plays small.
In other words, we have, with a good RHO, the altered (C):
(C') Half of the time when he hold JTx he plays the jack.
In this circumstance, (B)or(C') is just slightly more likely
than (A).
But against RHO player of uneven ability, the odds of (C) are
fairly low, the odds RHO will play the J from JTx are less;
with a beginner it is nearly nothing. In those instances,
you can apply restricted choice.
--
Thomas Andrews tho...@best.com http://www.best.com/~thomaso/
"Show me somebody who is always smiling, always cheerful, always
optimistic, and I will show you somebody who hasn't the faintest
idea what the heck is really going on." - Mike Royko
David desJardins
Thomas Andrews <tho...@shell3.ba.best.com> writes:
> Let's say you are declarer, Kx in hand and AQ9xxx in dummy.
> When you play the king, RHO plays the J.
>
> B) Half the time when he holds JT he plays the jack.
> C) Some of the time when he holds JTx he plays the jack.
> D) Some of the time when he holds Jx or Tx.
>
>
> In this circumstance, (B)or(C') is just slightly more likely
> than (A).
No, RHO is much more likely to hold (JT or JTx) than stiff J.
Stiff J is about 2.83%.
Doubleton JT is about 3.39%.
JTx is about 10.17%.
So half of (JT or JTx) is about 6.78%.
This comes out to be exactly 2.4 times as likely as stiff J.
David desJardins
David Ackerley
On Wed, 4 Mar 1998 st...@flash.net wrote:
<snip>
> > make it. In principle, this is similar to the situation with AQ9xxx
> > opposite Kx - if you cash the king and the ten or jack fall on your right
> > restricted choice would suggest that you hook the 9, but given that there
> > is nothing to prevent your RHO dropping an honour from JTx you would be a
> > bit of a mug to do so unless you had reason to suspect that they were
> > short in the suit. There are SOME falsecards that you should never pay
> > off to.
> >
> When RHO plays J or T on the first trick in your situation,
> there is a 33% chance that he holds the other honor (restricted
> choice), even given that he will falsecard 100% of the time
> with JTx.
> So hooking the 9 will win 67% of the time.
> However, the 3-2 split will occur apriori 71% (given no 5-0 split),
> so playing for the drop is still indicated here.
>
> If your RHO is a novice, OTOH, he must have stiff honor or JT tight.
> It's 2:1 in favor of the stiff, so the finesse is better.
> (67% of the time, LHO will hold Hxxx).
>
> -Stu Goodgold
>
These figures are simply not correct. Going back to the apriori, there
are 20 possibilities for the 3/2 break, assigning each card a label from
A to E:
3/2 breaks
AB CDE AC BDE
AD BCE AE BCD
BC ADE BD ACE
BE ACD CD ABE
CE ABD DE ABC
2/3 breaks
As above, only reversed
Say that A and B correspond to the jack and ten, respectively. Of the 20
possible scenarios, there are 4 where RHO will be dealt the jack and ten
together (3 of JTx, and one JT doubleton). Given that a 3/2 break is 71%
having excluded the 5/0, this adds up to roughly a 14% chance of RHO
holding JT or JTx. This compares with only a (29x0.5x2/5) roughly 6%
chance of them holding stiff J or T.
Even if your oppos are only good enough to remember to falsecard with JTx
one time in three, that is still enough to favour playing for the drop.
Of course, you are correct if they would NEVER false card that the hook
is the play to make, favoured by 6%:3.5%, or roughly 2:1.
But that's usually when you discover the hard way that they're playing
reverse count...
dgo...@bright.net
I responded earlier to a post which was going to finesse the 8 on the
second round. However, this problem is simply not possible because LHO
risks a certain trump trick by playing 9 from J9xx.
After some thought, it seems the 9 must have come from 2nd seat..RHO.
At first this seemed to be a guess, again, after some thought, RHO
cannot afford to falsecard with the 9 from J9xx because if partner has
the singleton 10, she has just given away a sure trick.
If the 9 comes from RHO, play the K next in case the 9 was a singleton.
Sue Picus/Barry Rigal
Richard Pavlicek wrote:
>
> Sue Picus/Barry Rigal wrote:
>
> > you have a trump suit of Q876 (dummy)
>
> > AK105 in hand
> >
> > You lead to the king; it goes 2K9.you are playing a slam and must play
> > the suit for no losers.
> >
> > What do you do next?
>
> queen is automatic. Perhaps, you meant "9K2" in which case
> I'd believe the 9 and cash the ace. RHO would be unlikely to
> falsecard with J9xx for fear of a stiff 10.
>
>
sorry!
What if AK105 is in dummy - so that the falsecard is risk free?
Barry
Eric Leong
Sue Picus/Barry Rigal (sue-...@worldnet.att.net) wrote:
: sorry!
: Barry
AK105 (dummy)
Q876
Your LHO plays the 9 when you cash the K. Who do you play for length?
Answer:
It depends on how strong a player your LHO is. A play of the 9 from J9xx
is virtually obligatory from a strong player. Since J9xx is three times
more likely than from a stiff 9, I would play LHO for the length.
On the other hand, I would doubt that a very weak player would not be
aware enough to play the 9 from J9xx more then a third of the time. So I
would play the very weak player for shortness.
Now the problem comes when you don't know how strong your LHO is (i.e. Is
LHO capable of playing the 9 from J9xx more than a third of the time?). But
there are certain techniques that comes with experience that you can use by
studying your LHO.
Examples:
1. Is his convention well filled out and show some
experience playing the game?
2. Did his comments about a previous hand seem rational?
3. Does he have a kibitzer?
Yes to any one of these questions would influence me to play LHO for J9xx.
Also, while you are thinking about this, you often will get lucky and an
opponent will give you a "tell" about the situation. Many long time
pro's would know what I am talking about but they naturally keep this to
themselves.
Eric Leong
st...@flash.net
In article <eleongEp...@netcom.com>,
When Barry posted his original query, he mentioned this was the
Cap Gemini. This, unfortunately, was not mentioned in the re-post.
You probably wouldn't find a national-level expert there, let alone
a 'very weak player' :-).
-Stu G.
Steve Grant
Steve Grant wrote:
>
> Sue Picus/Barry Rigal wrote:
> >
> >
> > consider yourself to be a world class player in the Cap Gemini.
> >
> >
> > AK105 in hand
> >
> > You lead to the king; it goes 2K9.you are playing a slam and must play
> > the suit for no losers.
> >
> > What do you do next?
> >
> > field? (contributors are being given a chance to display their
> > chauvinism!).
> >
> > Barry Rigal
>
> as one time in 3? Hard to believe she could have been invited to the
> Cap Gemini otherwise. So continue with the other high trump from hand.
>
> Or you could just say, "If trumps are 3-2, I'm solid." When nobody
> makes a move, you can write editorials in the Bridge World on the
> subject for years and years to come :)
>
> Maybe the best play was to come to hand in a side suit and *cash* a high
> honor from hand. Especially if you didn't have the ten....
>
> Steve
Good grief, is this garbled. I should have posted it in HTML, thus
sparing the majority of rgber's.
I was answering a completely different question from what Barry was
posing. Apologies to all.
Steve
Steve Grant
Sue Picus/Barry Rigal wrote:
>
> Richard Pavlicek wrote:
> >
> > Sue Picus/Barry Rigal wrote:
> >
> > > you have a trump suit of Q876 (dummy)
> >
> > > AK105 in hand
> > >
> > > You lead to the king; it goes 2K9.you are playing a slam and must play
> > > the suit for no losers.
> > >
> > > What do you do next?
> >
> > queen is automatic. Perhaps, you meant "9K2" in which case
> > I'd believe the 9 and cash the ace. RHO would be unlikely to
> > falsecard with J9xx for fear of a stiff 10.
> >
> >
> Exactly right.
>
> sorry!
>
> What if AK105 is in dummy - so that the falsecard is risk free?
>
> Barry
THIS is the question I was trying to answer in my original post(the
first round has gone: 6, 9, K, 2).
Cashing the ace next seems like an insult to LHO. If she's good enough
to get invited to the Generali, she's good enough to play 9 from J9xx at
least as often as one time in three. Which makes J9xx on your left at
least as likely as stiff 9.
Steve
David desJardins
Richard Pavlicek <pavl...@gate.net> writes:
>> you have a trump suit of Q876 (dummy), AK105 in hand
>
> In your play sequence a falsecard is inane, so low to the
> queen is automatic. Perhaps, you meant "9K2" in which case
> I'd believe the 9 and cash the ace. RHO would be unlikely to
> falsecard with J9xx for fear of a stiff 10.
That's not so very unlikely. If RHO has J9xx, then it's twice as likely
that declarer has AKTx (when falsecarding might gain a trick) as AKxx
(when falsecarding costs a trick).
The optimal strategy (if RHO knows that declarer has four trumps headed
by the AK) appears to be as follows. RHO should falsecard from J9xx
with probability 1/3. Declarer, holding AKTx, should play the ace or
queen equally often on the second round, when RHO does follow with the
nine.
If it's also possible that partner could hold stiff ace or stiff king,
then the falsecard from J9xx becomes less attractive (by an amount which
depends on how likely it is that partner holds a top honor).
David desJardins
Steve Grant
Congratulations on correcting a common misconception.
I don't quite agree with your percentages, though. Falsecarding w/ the
9 from J9xx as East is a "last straw" sort of play. It's *not* the
percentage play, though it may win more often than the percentage play
if East is willing to bet on the direction of South's gullibility. As
a practical matter, I think you *are* right -- most declarers would,
as Pavlicek did, assume the 9 was a singleton.
It's not the right assumption, though. South should safety against
East's J9xx *regardless* of whether East plays the 9 or an x.
Just for fun you may also want to consider whether it's really automatic
to play East to have blundered from J9xx if West follows with the ten.
Those Grosvenor Gambits can be tricky....
Steve
Sue Picus/Barry Rigal
Back to
AK105
facing Q876
When you lead to the K, LHO plays the 9.
Result of survey from the Cap Gemini.
Seven out of eight tables reached the excellent slam. The lucky Hacketts
were the exception.
5 out of 7 tables believed West was falsecarding, and went down. Two
tables believed the card to be a singleton... and made the slam.
The Berkowitzes were happy campers. Lisa played the Chinese lady
defender not to have falsecarded - not a surprise I think...
David's partner Larry Cohen played Lanzarotti/Buratti not to have
falsecarded - that IS a surprise I think.
Afterwards David said he would not have been able to stand the
embarassment if he had fallen for the sucker punch.
Result (as I said in my article) Themistocles Papadopoulos - tyhe only
man capable of falsecarding with a singleton - lives!
Barry Rigal
Edward Sheldon
B. K. Oxley (binkley) wrote:
> Sue Picus/Barry Rigal wrote:
[I have to do some snipping to allow me to post - sorry]
> >you have a trump suit of Q876 (dummy)
> >
> > AK105 in hand
> >
> >You lead to the king; it goes 2K9.you are playing a slam and must play
> >the suit for no losers.
[snip]
> Ignoring the silly question about the women players, I'll lead low from
> hand, and if nothing interesting happens, finesse the 8.
>
> Given that the 2, 3 and 4 are out, and that these opponents are most
> unlikely to give any sort of accurate count in trump (especially since you
> present this as a single-suit problem), the 9 is more likely from J9 or J943
> than from 943, 94 or 93. But I'll pay off if it is.
>
> RHO having played the 2, he is unlikely to have the 3 by Restricted Choice.
> What I have to worry about most is a clever LHO playing the 9 without the J
> in an attempt to get me to finesse her.
>
> This position is vastly easier against trustworthy, weak opponents!
I am mystified by this. If LHO has J9xx, he can guarantee a trick
by playing small. Binkley's line caters for LHO's Grosvenor with J9xx,
but pays off to 9x and 9xx, which together are more than three times
as likely as J9xx.
I can see no reason to do anything other than cash the Queen, even
against
a pair who finished last or second from last.
Cheers,
Ed
Giuseppe Bianchi
David desJardins <de...@math.berkeley.edu> wrote:
>The optimal strategy (if RHO knows that declarer has four trumps headed
>by the AK) appears to be as follows. RHO should falsecard from J9xx
>with probability 1/3. Declarer, holding AKTx, should play the ace or
>queen equally often on the second round, when RHO does follow with the
>nine.
Maybe I'm missing something, but I really cannot understand why one
should play the 9 1/3 of the time, to "protect" the case of stiff 9.
If you do not falsecard, declarer has no losing option, and this fact
must be accounted for.
Assume that declarer is aware that the falsecard is three times more likely
than the stiff 9, and thus always plays for the falsecard.
Now, if I *always* falsecard, the expected gain (+1 = contract goes down,
-1 = contract makes) is given as follows:
e[G] = (3/4 * -1) in 3/4 of the cases I have J9xx, I always falsecard,
and declarer always guesses right
+
1/4 * 1 in 1/4 of the cases I have the stiff 9, and thus
declarer misguesses
=
-1/2
Now, if I falsecard only 1/3 of the cases, then the gain is:
e[G] = 1/2 * -1 in 2/3 of the 3/4 cases of J9xx (=1/2 total cases)
i do not falsecard. But then declarer has no
losing option and the contract makes.
+
1/4 * -1 In the remaining case I falsecard and declarer
guesses right
+
1/4 * 1 the case of stiff 9
= -1/2
Therefore, my strategy does not affect at all the expected gain. You
may easily see that any strategy I choose does not change my expected
gain!
The only way to increase the expected gain is to change declarer's play
strategy. But this is exactly what in practice happens when declarer is
not good, or declarer "thinks" you are not good!
Hence, in any case, falsecarding (in this case, as in all "mandatory"
falsecarding cases), opposite *any* declarer, is the only way to increase
your chances.
At least if I'm not missing something... :-)
Giuseppe.
David desJardins
Then you should do the math yourself. I'd be happy to see your figures,
but you can't come up with the correct figures just by waving your hands
and arguing subjectively. You have to do a computation, as I have.
Giuseppe Bianchi <bia...@meteor.comet.columbia.edu> writes:
> Maybe I'm missing something, but I really cannot understand why one
> should play the 9 1/3 of the time, to "protect" the case of stiff 9.
> If you do not falsecard, declarer has no losing option, and this fact
> must be accounted for.
There are three relevant cases:
A. Declarer holds AKxx, you hold J9xx, partner holds T. (6 cases)
B. Declarer holds AKTx, you hold J9xx, partner holds x. (12 cases)
C. Declarer holds AKTx, you hold 9, partner holds Jxxx. (4 cases)
If you always falsecard from J9xx, and declarer can deduce that fact,
then declarer cashes the queen next when you play the nine. Declarer
picks up case A and case B, for a total of 18 out of 22 cases.
If you never falsecard from J9xx, and declarer can deduce that fact,
then declarer cashes the ace next when you play the nine. Declarer
picks up case B and case C, for a total of 16 out of 22 cases.
However, if you falsecard from J9xx with probability 1/3, then the best
declarer can do, regardless of how much he knows about you, is to pick
up one-third of case A and all of case B, for a total of 14 out of 22
cases. Thus this is better for you than either of the pure strategies.
> Assume that declarer is aware that the falsecard is three times more
> likely than the stiff 9, and thus always plays for the falsecard.
> ....
> Therefore, my strategy does not affect at all the expected gain. You
> may easily see that any strategy I choose does not change my expected
> gain!
It appears that you have completely ignored case A, which is the main
point of the analysis. Certainly, if you assume that declarer will play
you to have falsecarded when you play the nine, then you should never
falsecard, because it costs you when partner has the stiff ten, and it
never gains (under that assumption).
David desJardins
Steve Grant
David desJardins wrote:
>
> Steve Grant <ACE...@concentric.net> writes:
> > I don't quite agree with your percentages, though.
>
> Then you should do the math yourself. I'd be happy to see your figures,
> but you can't come up with the correct figures just by waving your hands
> and arguing subjectively. You have to do a computation, as I have.
This is slightly more condescending than I expect from you, David.
> If you always falsecard from J9xx, and declarer can deduce that fact,
> then declarer cashes the queen next when you play the nine. Declarer
> picks up case A and case B, for a total of 18 out of 22 cases.
>
> If you never falsecard from J9xx, and declarer can deduce that fact,
> then declarer cashes the ace next when you play the nine. Declarer
> picks up case B and case C, for a total of 16 out of 22 cases.
And exactly how is declarer supposed to "deduce that fact" in either
case? This is why your strategy is a "straw strategy." Sure, it
may do better than the percentage play _if you can predict the
direction of your opponent's ignorance_. If you're willing to make
that sort of bet at the table, fine. Just be sure to realize that
if you're wrong about your opponent's proclivities, you will do
worse than the percentage play.
Steve
Giuseppe Bianchi
David desJardins <de...@math.berkeley.edu> wrote:
>A. Declarer holds AKxx, you hold J9xx, partner holds T. (6 cases)
>B. Declarer holds AKTx, you hold J9xx, partner holds x. (12 cases)
>C. Declarer holds AKTx, you hold 9, partner holds Jxxx. (4 cases)
>
Yes. Let's clarify the misunderstanding. I assumed (and I guess Steve,
too) the thread was dealing with the problem of *mandatory* falsecarding
as explicitely restated by Barry [AKTx in dummy or, better - to avoid the
annoying case of stiff Q, which requires to place some additional spot
card - declarer that starts cashing the A, and partner follows small].
To make it clear for the other readers, in this case (considered in my
post), the 9 MUST be played 100% of the times in order to provide a
losing situation for a non optimal declarer (from this the name
"mandatory" falsecard).
Only now I realize that you are addressing the initial problem, i.e.
whether to play the 9 seeing in dummy Q876. Now, this is a completely
different matter, as this is no more a "mandatory" falsecard, but an
"optional" one, as the falsecard let a cold-down-1 contract make once
every three times (As David clearly explained, when you do not see the
T, chances are 6/18 that this is in partner's hand).
However, despite I now fully agree with your numbers, I never falsecard in
this position. I cannot neglect the psychological fact that, when parter
T drops, if partner and teammates haven't a solid math background,
the explanation process can be long and quite painful :-)
Donald A. Varvel
In <6djj27$n...@bgtnsc03.worldnet.att.net> Sue Picus/Barry Rigal
<sue-...@worldnet.att.net> writes:
>
>falsecards in highclass fields is a timely theme.
>
>consider yourself to be a world class player in the Cap Gemini.
>
>
> AK105 in hand
>
>You lead to the king; it goes 2K9.you are playing a slam and must play
>the suit for no losers.
>
>
the
>field? (contributors are being given a chance to display their
>chauvinism!).
It should be noted that said women pairs finished 2nd and 3rd in
the Macallen.
-- Don Varvel
Henk Uijterwaal (RIPE-NCC)
On 8 Mar 1998, Donald A. Varvel wrote:
> In <6djj27$n...@bgtnsc03.worldnet.att.net> Sue Picus/Barry Rigal
> <sue-...@worldnet.att.net> writes:
> >
> >falsecards in highclass fields is a timely theme.
> >
> >consider yourself to be a world class player in the Cap Gemini.
> >
> >you have a trump suit of Q876 (dummy)
> >
> > AK105 in hand
> >
> >You lead to the king; it goes 2K9.you are playing a slam and must play
> >the suit for no losers.
> >
> >What do you do next?
Before you decide, there is one more thing to consider. At the table
where I was watching, dummy had shown a singleton spade, 4H, 4+D, 1st or
2nd round club control and 3 keycards. Still, the opening lead was the
CA, which seems to make much more sense if you hold a potential trump
trick than when you don't. At least, this is what Marcello Branco claimed
after considering the situation for a Marlboro or two and getting it
wrong.
> It should be noted that said women pairs finished 2nd and 3rd in
> the Macallen.
But I'd consider the women pairs in the MacAllan (Smith-Davies and
Auken-von Arnim) to be significantly stronger that the pairs in the Cap
Gemini (Sun-Wang and Berkowitz-Letizia). Also, I think that the field in
the MacAllan was somewhat weaker than the field in the Hague.
Henk
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------------------------------------------------------------------------------
%DCL-E-NOCFFE, unable to locate coffee - keyboard input suspended.
John (MadDog) Probst
In article <3500CE89...@concentric.net>, Steve Grant
<ACE...@concentric.net> writes
This is just a classic case of mixed strategy with a saddle point. It is
closely related to bluffing frequency at poker, and should be driven by
a fact you know but the oppo don't which gives you a frequncy of 1 in 3.
I can think of several trivial games where this strategy applies.
--
John (MadDog) Probst| /|_??? NO! _}\ |phone before fax to:
451 Mile End Road | / @\__. __/# \ |181 980 4947
London E3 4PA | /\ __) {-- \ |jo...@probst.demon.co.uk
+44-(0)181 983 5818 | /\:\ .--' ~~\ /\ |Dealing is my best game
Kent Feiler
st...@flash.net wrote:
>Larry Cohen has an article in the Feb 98 ACBL Bulletin (p. 102)
>on the Politiken World Pairs in Copenhagen during Nov. 97.
>None vul.
> K3
> J32
> Q987
> QT97
> 9 AJ85
> K65 AQ874
> AKJT2 4
> AK43 J52
> QT7642
> T9
> 653
> 86
>
>Of the eight tables, 3 EW played in 6H, the other 5 in 7H.
>To quote Cohen: "All five declarers in the grand slam went down,
>however. They reasonably chose to play for 4-3 diamonds and no
>worse than 6-2 spades (sic). They won a trump opening lead with
>dummy's king and played the SA, spade ruff, DA, diamond ruff,
>spade ruff and - oops! - they were overruffed. Maybe the
>fall of the SK should have gotten them to change their minds,
>but it easily could have been from SKQ3 or a falsecard from
>SKQ63 or the like."
>What bothers me is why no one played that line after seeing the
>SK on the second spade. The rule of restricted choice makes
>it twice as likely to be from K3 rather than KQ3 if it is a true
>card. Granted the majority of these world class defenders would be
>up to the false card; but doesn't the rule of restricted choice
>also apply here. If you are falsecarding from KQ63, aren't you
>going to play the K half the time and the Q the other half??
>After all the falsecard objective is to make it look like you
>have a doubleton?
------------------------------------------------------------------------------
There are all sorts of entertaining variations on this theme. The
first thing I do in cases like this is look at LHO's carding, I'm more
inclined to believe that than RHO's honor. This actually adds to the
restricted choice question, what are the odds that RHO falsecarded
with KQx AND LHO miscounted the suit on his side. This is obviously
less reliable in slam contracts than games or partscores, and less
reliable at higher levels, but a lot of people get into the habit of
counting suits and do it even at inappropriate times. Some get into
the habit of miscounting, which is just as good.
But...I don't think that the 2 to 1 odds that apply to the situation
where you have nine trump and drop the J or Q necessarily apply to
this situation. With 5 cards between your two hands and 8 cards in
the opponents hands, the odds favor the more even breaks, i.e. 5-3 is
more likely than 6-2.
Regards,
Kent Feiler
Communications Programming, Inc
http://www.cpiusa.com/
kfe...@cpiusa.com
David desJardins
Stu Goodgold <st...@flash.net> writes:
> K3
> J32
> Q987
> 9 QT97 AJ85
> K65 AQ874
> AKJT2 4
> AK43 QT7642 J52
> T9
> 653
> 86
> What bothers me is why no one played that line after seeing the
> SK on the second spade. The rule of restricted choice makes
> it twice as likely to be from K3 rather than KQ3 if it is a true
> card.
A priori, it's 9.8 times more likely that North holds (KQx or KQxx or
KQxxx) than that North holds Kx. So even if North falsecards only half
the time from those holdings, and thus plays the king with probability
1/4, that still means that there's a 71% chance in this situation that
North has a third spade. That seems obviously better odds than the
ruffing finesse.
David desJardins
Eric Taylor
Sue Picus/Barry Rigal wrote:
> falsecards in highclass fields is a timely theme.
>
> consider yourself to be a world class player in the Cap Gemini.
>
> you have a trump suit of Q876 (dummy)
>
> AK105 in hand
>
> You lead to the king; it goes 2K9.you are playing a slam and must play
>
> the suit for no losers.
>
> What do you do next?
>
> what would you do if you were playing against the two women pairs in
> the
> field? (contributors are being given a chance to display their
> chauvinism!).
IF LHO has J9xx, then he/she had a natural trump trick the whole time
no?
So I play low to the queen.
Eric Taylor
Sue Picus/Barry Rigal wrote:
> falsecards in highclass fields is a timely theme.
>
> consider yourself to be a world class player in the Cap Gemini.
>
> you have a trump suit of Q876 (dummy)
>
> AK105 in hand
>
> You lead to the king; it goes 2K9.you are playing a slam and must play
>
> the suit for no losers.
>
The 9 appears on your right.
A very nice play if from J9xx.
I will go for the "how I would feel factor".....
If I failed to pick up the suit when RHO falsecarded with 9x, I do not
think I could look partner in the face again.
If I failed to pick up the suit when RHO falsecarded with J9xx,
I could congratulate RHO on his/her play and I think partner would
forgive me. :)
So.....
I play the trump ace as well.