Hi Dear Mr Wolff
There are a couple of interesting points. Suppose dummy wins the lead with ten and leads K of diamonds. Now, since east doesn’t know whether south has singleton or doubleton diamonds, ( West did not get chance to indicate count in diamonds) he might just duck. If west wins D A there never is any problem. Now dummy can cash spade A and lead J of hearts . If east holds Q to three carded or Q nine doubleton, south straightaway makes and even if West wins, he might return a black suit. He must precisely lead a diamond and east must lead Q of clubs and south must not guess correctly for the contract to go down. However if if east elects to play A of diamond ( perhaps improbable) and returns Q of clubs , south has not lost anything, he tried and might even make the contract on the principle of restricted choice
Regards
bobbywolffJuly 6th, 2021 at 2:49 pm
Hi AVRR,
While you may be on target psychologically (remains to be seen) you will lose, if West happened to be dealt the singleton ace of diamonds, an unlikely event, but still, in the absence of an adequate counter argument (I think here) the overtake of the spade in hand still looks best.
And regarding the general club distribution and the various combinations possible, (as there would be in any side suit) will allow a “real” chance for even a top declarer to misread.
It will and has come up many times in my long years of experience and often forces declarer to be right in his guesses in order to navigate a success, but only if the defenders are capable of understanding the subterfuge necessary by that clever defense.
Of course, the declarer needs to understand that the defenders he is encountering are capable of executing that guess, which, in turn, is IMHO just as important as the close percentages which go along with that sometimes over spoken restricted choice option, except of course, when top players are occupying at least the two seats involved, declarer and his RHO opponent.
A final word to the wise, declarer’s LHO will usually quickly fall into line by winning his ace, assuming he possesses it, and lead a small one back, anytime that play might win which indeed will often contain both winning and losing opportunities. Playing the king by declarer immediately on the lead of the queen or jack
is clearly (in the absence of clear evidence) mandated, but the low one coming back is not.
No doubt this particular card combination, back and forth, ranks very highly among significant
opportunities for both the declarer and his opponents to show their bridge acumen.
Jeff SJuly 6th, 2021 at 3:21 pm
I’ve spent a long time now trying to twist and turn to find some way to force West to lead the first club but there just doesn’t seem to be a way. Even if you take on the board and lead a diamond followed by a heart, South can eventually throw in West with a heart, but West can lead a diamond, but can also lead a spade and South will still be forced to lead a second diamond to the ace.
In the end, the hand seems very pure. South simply has to get the clubs right when West takes his ace and leads back that nasty low club.
bobbywolffJuly 6th, 2021 at 4:30 pm
Hi Jeff S,
You seem to have a very “keen” habit of (at least apparently) learning as you go or I should say “progressive”.
And, if you continue doing just that, situations to which you formerly considered difficult or even next to impossible, will melt like snow in Spring.
The hand today is a prime example of very high-level combatants at war with one another except the weapons used are only designed to challenge “ego” instead of life itself.
And, in truth, whomever wins an individual battle, feels good, but even the loser (opponent guesses right) is really not the loser, since all they can do is force the declarer to guess, rather than to have it presented on a platter to them.
Both sides are winners, but to the one who guessed correctly, go the spoils.
David WarheitJuly 6th, 2021 at 6:25 pm
The thinking necessary on this hand by declarer is actually fairly simple. When E wins the DA, he must return a C in order to have any chance of defeating the contract. If he leads the A or a small C, contract makes. Therefore his only choice is to lead either the Q or the J, so that’s what he does. Knowing that, what are the chances that he has both the Q and the J? versus only the one he led? Well, we all know the answer to that; case closed.
bobbywolffJuly 6th, 2021 at 6:48 pm
Hi David,
As usual, your analysis and especially your presentation concerning “Restrictive Choice” is certainly up to and perhaps even more instructive than would Terence Reese’s might have been.
Having said that and, of course, playing the devil’s advocate, would or could this specific example be affected by the likely extraneous reason of both the possibility of leading neither
and even the thought of another perhaps psychologically more or less, indigenous factor?
Your move or, at the least, has the case been reopened?
Very instructive hand and commentary. I was reading just yesterday the mathematician and philosopher Barry Mazur’s article on “Shadows of Evidence”. The principle of restricted choice, as a type of evidence, comes up frequently, but recognizing it and harnessing it correctly is counterintuitive.
Thanks for the kind comment and feel free to forward it to anyone who won’t be too frightened by it – or maybe they should read it. In the absence of Face to Face bridge
I’ve been spending more time on this.
Regards,
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Hi Dear Mr Wolff
There are a couple of interesting points. Suppose dummy wins the lead with ten and leads K of diamonds. Now, since east doesn’t know whether south has singleton or doubleton diamonds, ( West did not get chance to indicate count in diamonds) he might just duck. If west wins D A there never is any problem. Now dummy can cash spade A and lead J of hearts . If east holds Q to three carded or Q nine doubleton, south straightaway makes and even if West wins, he might return a black suit. He must precisely lead a diamond and east must lead Q of clubs and south must not guess correctly for the contract to go down. However if if east elects to play A of diamond ( perhaps improbable) and returns Q of clubs , south has not lost anything, he tried and might even make the contract on the principle of restricted choice
Regards
Hi AVRR,
While you may be on target psychologically (remains to be seen) you will lose, if West happened to be dealt the singleton ace of diamonds, an unlikely event, but still, in the absence of an adequate counter argument (I think here) the overtake of the spade in hand still looks best.
And regarding the general club distribution and the various combinations possible, (as there would be in any side suit) will allow a “real” chance for even a top declarer to misread.
It will and has come up many times in my long years of experience and often forces declarer to be right in his guesses in order to navigate a success, but only if the defenders are capable of understanding the subterfuge necessary by that clever defense.
Of course, the declarer needs to understand that the defenders he is encountering are capable of executing that guess, which, in turn, is IMHO just as important as the close percentages which go along with that sometimes over spoken restricted choice option, except of course, when top players are occupying at least the two seats involved, declarer and his RHO opponent.
A final word to the wise, declarer’s LHO will usually quickly fall into line by winning his ace, assuming he possesses it, and lead a small one back, anytime that play might win which indeed will often contain both winning and losing opportunities. Playing the king by declarer immediately on the lead of the queen or jack
is clearly (in the absence of clear evidence) mandated, but the low one coming back is not.
No doubt this particular card combination, back and forth, ranks very highly among significant
opportunities for both the declarer and his opponents to show their bridge acumen.
I’ve spent a long time now trying to twist and turn to find some way to force West to lead the first club but there just doesn’t seem to be a way. Even if you take on the board and lead a diamond followed by a heart, South can eventually throw in West with a heart, but West can lead a diamond, but can also lead a spade and South will still be forced to lead a second diamond to the ace.
In the end, the hand seems very pure. South simply has to get the clubs right when West takes his ace and leads back that nasty low club.
Hi Jeff S,
You seem to have a very “keen” habit of (at least apparently) learning as you go or I should say “progressive”.
And, if you continue doing just that, situations to which you formerly considered difficult or even next to impossible, will melt like snow in Spring.
The hand today is a prime example of very high-level combatants at war with one another except the weapons used are only designed to challenge “ego” instead of life itself.
And, in truth, whomever wins an individual battle, feels good, but even the loser (opponent guesses right) is really not the loser, since all they can do is force the declarer to guess, rather than to have it presented on a platter to them.
Both sides are winners, but to the one who guessed correctly, go the spoils.
The thinking necessary on this hand by declarer is actually fairly simple. When E wins the DA, he must return a C in order to have any chance of defeating the contract. If he leads the A or a small C, contract makes. Therefore his only choice is to lead either the Q or the J, so that’s what he does. Knowing that, what are the chances that he has both the Q and the J? versus only the one he led? Well, we all know the answer to that; case closed.
Hi David,
As usual, your analysis and especially your presentation concerning “Restrictive Choice” is certainly up to and perhaps even more instructive than would Terence Reese’s might have been.
Having said that and, of course, playing the devil’s advocate, would or could this specific example be affected by the likely extraneous reason of both the possibility of leading neither
and even the thought of another perhaps psychologically more or less, indigenous factor?
Your move or, at the least, has the case been reopened?
Very instructive hand and commentary. I was reading just yesterday the mathematician and philosopher Barry Mazur’s article on “Shadows of Evidence”. The principle of restricted choice, as a type of evidence, comes up frequently, but recognizing it and harnessing it correctly is counterintuitive.
It has taken me time to accept it, and yes, my own personal experience is that it is not perfect, but useful. Another recent discussion: https://pubs.aeaweb.org/doi/pdfplus/10.1257/jep.33.3.144
Back to a theme presented here often, the educational value of bridge in our schools—examples of probabilistic reasoning like this are very valuable.
BTW, thanks to Ian for his informative link regarding food and waste
Forgot to add:
https://www.simonsfoundation.org/2013/02/21/shadows-of-evidence/
Hi Joe1,
Thanks for the kind comment and feel free to forward it to anyone who won’t be too frightened by it – or maybe they should read it. In the absence of Face to Face bridge
I’ve been spending more time on this.
Regards,
Iain