[bab9]

Given that there is bidding theory, is there also discarding theory?

I am aware that there are a number of discarding systems: odds/even, high/low, McKenny, are these based on some sort of discarding theory? If so, can you direct me to a book on the subject?

[Cascade]

Defensive Signals, Marshall Miles 1995

[jukmoi]

Partnership defence by Woolsey.

[dicklont]

Eddie Kantar teaches modern bridge defense.
Eddie Kantar teaches advanced bridge defense.

Very good books.

[P_Marlowe]

Hi,

Yes there also exists theory for discarding / signaling.

In the end signaling theory is all about encoding the information of your
hand using color and rank.
So signaling / discardng theory is just a subset of information / encoding
theoy, both are large topics.

If I recall it correctly, there was a post on BBF, which gave a link to a
translation of a paper, which explained Slavinsky signals.
Also you may have a look at Prism signals, e.g.

http://prismsignals.com/PDFonline.pdf

An example
If you look at certain signals, e.g. attidude / count, you will discover,
that certain forms of signals work better together than others,
if you signal low for pos. attitude, that the low - high count signla works
better with this, if you signal high for pos., than high - low works better
with this.

With kind regards
Marlowe

[bab9]

Thankyou. Hopefully these books explain why you are required to discard in a particular way: advantages and disadvantages.

Not yet found the link on Slavinsky signals.

I recall reading a post on BBF that Prism signals were illegal as they were classed as encoded signals. Is this the case, or can you use them in events?

[jukmoi]

Well the Woolsey books is not much about discarding systems. Its more about how to use and read signals. When to use count, attitude or suit preference. Still it is the best book about signalling that I have read.

[Stephen Tu]

Pretty sure Prism signals are parity signals based on dummy suit lengths, information available to declarer, therefore not encrypted and legal.

But I've never really seen any top pairs that used them. I think the main argument is that they require quite a bit of mental effort that is probably better spent on other things, and rather rarely have the big success of removing the guess vs. more traditional methods.

It's just more important to improve your overall defense period. At a basic/intermediate level, Root's Defense book and Kantar's books mentioned above are excellent. Miles/Woolsey books mentioned above are good followups on signalling (Woolsey first, Miles is targeted to an advanced audience). And "Killing Defence at Bridge" by Kelsey is a must-read. All the books talk about discarding to some extent.

[bill1157]

Paul Marston had an interesting article on signaling and discarding in Australian Bridge last year. The gist of it was that you should discard cards you could afford to let go, and that you (on the other side of the table) could draw inferences from that. I.e. Partner isn't discarding from qxx in certain situations.

Bill

[barryallen]

Stephen Tu, on Aug 18 2010, 02:31 AM, said:

Pretty sure Prism signals are parity signals based on dummy suit lengths, information available to declarer, therefore not encrypted and legal.

But I've never really seen any top pairs that used them. I think the main argument is that they require quite a bit of mental effort that is probably better spent on other things, and rather rarely have the big success of removing the guess vs. more traditional methods.

It's just more important to improve your overall defense period. At a basic/intermediate level, Root's Defense book and Kantar's books mentioned above are excellent. Miles/Woolsey books mentioned above are good followups on signalling (Woolsey first, Miles is targeted to an advanced audience). And "Killing Defence at Bridge" by Kelsey is a must-read. All the books talk about discarding to some extent.

I can't imagine prism signals being illegal, their weak point being that they give declarer the same information as the defence. I would guess that information is more useful most of the time to declarer than the defence? Never found them complex, once you unwrap the terminology they are usually presented with. Would be very interested to hear from anyone who has used them for an extended period.

[hrothgar]

bab9, on Aug 17 2010, 05:48 AM, said:

Given that there is bidding theory, is there also discarding theory?

If you're really concerned about theory, the following is probably a good starting point

http://cm.bell-labs.com/cm/ms/what/shannon...shannon1948.pdf

[zenko]

barryallen, on Aug 18 2010, 06:42 AM, said:

Stephen Tu, on Aug 18 2010, 02:31 AM, said:

Pretty sure Prism signals are parity signals based on dummy suit lengths, information available to declarer, therefore not encrypted and legal.

But I've never really seen any top pairs that used them.  I think the main argument is that they require quite a bit of mental effort that is probably better spent on other things, and rather rarely have the big success of removing the guess vs. more traditional methods.

It's just more important to improve your overall defense period.  At a basic/intermediate level, Root's Defense book and Kantar's books mentioned above are excellent.  Miles/Woolsey books mentioned above are good followups on signalling (Woolsey first, Miles is targeted to an advanced audience).  And "Killing Defence at Bridge" by Kelsey is a must-read.  All the books talk about discarding to some extent.

I can't imagine prism signals being illegal, their weak point being that they give declarer the same information as the defence. I would guess that information is more useful most of the time to declarer than the defence? Never found them complex, once you unwrap the terminology they are usually presented with. Would be very interested to hear from anyone who has used them for an extended period.

I have been using them for quite a while, I do no recall ever that it helped declarer. Grated they rarely make a difference for defence too, (usually you have to have 3 small trumps to use it, and even then often it does not matter), but when it does help it helps tremendously, often in high level contracts. It takes a bit if an effort thou, so if it feels like distraction and you primarily play matchpoints it is probably not worth the trouble. For starter I would suggest trying straight up Vinje parity trump echo and if you like it go ahead and try to upgrade to Prism.

[zenko]

bab9, on Aug 18 2010, 01:27 AM, said:

Thankyou. Hopefully these books explain why you are required to discard in a particular way: advantages and disadvantages.

Not yet found the link on Slavinsky signals.

I recall reading a post on BBF that Prism signals were illegal as they were classed as encoded signals. Is this the case, or can you use them in events?

http://www.ugcs.caltech.edu/~forster/bridg...nski/index.html

[barryallen]

zenko, on Aug 18 2010, 09:51 AM, said:

barryallen, on Aug 18 2010, 06:42 AM, said:

Stephen Tu, on Aug 18 2010, 02:31 AM, said:

Pretty sure Prism signals are parity signals based on dummy suit lengths, information available to declarer, therefore not encrypted and legal.

But I've never really seen any top pairs that used them.  I think the main argument is that they require quite a bit of mental effort that is probably better spent on other things, and rather rarely have the big success of removing the guess vs. more traditional methods.

It's just more important to improve your overall defense period.  At a basic/intermediate level, Root's Defense book and Kantar's books mentioned above are excellent.  Miles/Woolsey books mentioned above are good followups on signalling (Woolsey first, Miles is targeted to an advanced audience).  And "Killing Defence at Bridge" by Kelsey is a must-read.  All the books talk about discarding to some extent.

I can't imagine prism signals being illegal, their weak point being that they give declarer the same information as the defence. I would guess that information is more useful most of the time to declarer than the defence? Never found them complex, once you unwrap the terminology they are usually presented with. Would be very interested to hear from anyone who has used them for an extended period.

I have been using them for quite a while, I do no recall ever that it helped declarer. Grated they rarely make a difference for defence too, (usually you have to have 3 small trumps to use it, and even then often it does not matter), but when it does help it helps tremendously, often in high level contracts. It takes a bit if an effort thou, so if it feels like distraction and you primarily play matchpoints it is probably not worth the trouble. For starter I would suggest trying straight up Vinje parity trump echo and if you like it go ahead and try to upgrade to Prism.

Ty for the reply. My basis here may be off, but it was mainly because of slams that put me off prism signals. Because it can give the declarer very similar information if he bothers to work it out. My belief was that I expected him to have more options open to make use of these signals? The biggest gain I imagined would be the oppositions unfamiliarity with the signals?

[matmat]

hrothgar, on Aug 18 2010, 07:32 AM, said:

bab9, on Aug 17 2010, 05:48 AM, said:

Given that there is bidding theory, is there also discarding theory?

If you're really concerned about theory, the following is probably a good starting point

http://cm.bell-labs.com/cm/ms/what/shannon...shannon1948.pdf

I might have to read this.

[TimG]

matmat, on Aug 18 2010, 01:31 PM, said:

hrothgar, on Aug 18 2010, 07:32 AM, said:

bab9, on Aug 17 2010, 05:48 AM, said:

Given that there is bidding theory, is there also discarding theory?

If you're really concerned about theory, the following is probably a good starting point

http://cm.bell-labs.com/cm/ms/what/shannon...shannon1948.pdf

I might have to read this.

All 55 pages?

[zenko]

barryallen, on Aug 18 2010, 01:07 PM, said:

zenko, on Aug 18 2010, 09:51 AM, said:

barryallen, on Aug 18 2010, 06:42 AM, said:

Stephen Tu, on Aug 18 2010, 02:31 AM, said:

Pretty sure Prism signals are parity signals based on dummy suit lengths, information available to declarer, therefore not encrypted and legal.

But I've never really seen any top pairs that used them.  I think the main argument is that they require quite a bit of mental effort that is probably better spent on other things, and rather rarely have the big success of removing the guess vs. more traditional methods.

It's just more important to improve your overall defense period.  At a basic/intermediate level, Root's Defense book and Kantar's books mentioned above are excellent.  Miles/Woolsey books mentioned above are good followups on signalling (Woolsey first, Miles is targeted to an advanced audience).  And "Killing Defence at Bridge" by Kelsey is a must-read.  All the books talk about discarding to some extent.

I can't imagine prism signals being illegal, their weak point being that they give declarer the same information as the defence. I would guess that information is more useful most of the time to declarer than the defence? Never found them complex, once you unwrap the terminology they are usually presented with. Would be very interested to hear from anyone who has used them for an extended period.

I have been using them for quite a while, I do no recall ever that it helped declarer. Grated they rarely make a difference for defence too, (usually you have to have 3 small trumps to use it, and even then often it does not matter), but when it does help it helps tremendously, often in high level contracts. It takes a bit if an effort thou, so if it feels like distraction and you primarily play matchpoints it is probably not worth the trouble. For starter I would suggest trying straight up Vinje parity trump echo and if you like it go ahead and try to upgrade to Prism.

Ty for the reply. My basis here may be off, but it was mainly because of slams that put me off prism signals. Because it can give the declarer very similar information if he bothers to work it out. My belief was that I expected him to have more options open to make use of these signals? The biggest gain I imagined would be the oppositions unfamiliarity with the signals?

Well that helps for sure, in a sense that declarer has to process info that he is unfamiliar with, but there is far more to it. The key is that the information available from bidding is usually not symmetrical, meaning declarer usually knows from bidding much less about defenders hands than vice versa, and without those clues it is usually much harder for him to figure out the defender's exact distribution (say is it 2335, or 4333, trump being a 3 card suit).

Of course, in general do signals help declarer too much is a good question and that applies to these signals too, but nobody says you have to signal honesty if you feel it might help the declarer more. Good thing about it is that if you decide to false card Prism signal it is often quite easy for the other defender to notice that you can not have the distribution that you are showing, and not so easy for declarer, again because of that asymmetrical info from the bidding, as well because of other clues from carding. Say for example when leading 3/5 pard leads the 3 and you have (and hide) the 2, and then he Prism signals showing even number of cards in that suit then you know he is false carding, but declarer can not know that.