Encrypted bidding

[DinDIP]

Help please! I'm reviewing Peter Winkler's book "Bridge at the Enigma Club" -- great book that you should read if you haven't yet done so -- for The Bridge World. I wanted to clarify whether it is true, as a number of websites state, that encrypted bidding is banned. The ACBL, WBF and ABF (as well as other BF) system regulations explicitly state that encrypted signals are not permitted. But I can't find anything that proscribes encrypted bidding. Have I missed something? Are there jursidictions where encrypted bidding is permitted?

 

Thanks in adavnce

 

David

[bluejak]

It is certainly legal in England/Wales. As I read the regulations it is certainly legal under WBF/EBL guidelines. Knowing the general Australian approach I cannot believe it is illegal there.

 

My guess would be that encrypted bidding is legal in most of the world. But I would be more careful before I started using it in the ACBL. However, I am not sure even in the ACBL: I cannot remember anything that makes it illegal there.

[mjj29]

It is certainly legal in England/Wales. As I read the regulations it is certainly legal under WBF/EBL guidelines. Knowing the general Australian approach I cannot believe it is illegal there.

It is legal in the EBU and I have played a system including encrypted bidding. Unfortunately, what we found was that in order to comply with the rest of the regulations you don't end up generating a shared key very often, so it's not all that useful. Other suggestions welcome though.

[nigel_k]

I'm intrigued by this idea. What sort of things can you use as an encryption key? If it has to be based on the current hand I have no idea how you could do it, but if not, it is quite easy. For example, base it on the total number of tricks your side has taken in the session so far. If that sort of thing is not illegal, it should be.

[campboy]

I'm intrigued by this idea. What sort of things can you use as an encryption key? If it has to be based on the current hand I have no idea how you could do it, but if not, it is quite easy. For example, base it on the total number of tricks your side has taken in the session so far. If that sort of thing is not illegal, it should be.

One standard situation is to play that certain types of raise promise one of the top two trump honours; if partner has the other one you now have a shared key (at least until dummy goes down).

[iviehoff]

For example, base it on the total number of tricks your side has taken in the session so far. If that sort of thing is not illegal, it should be.

That's not encryption, it's non-disclosure.

 

Consider the following. You are a defender and see a 10-count on table after the opening lead. Declarer showed 15-16 in the bidding. You now know, to within a point, how many high-card points your partner has. You also know that your partner knows how many HCP you have, to within a point. Declarer doesn't know this, at least not yet. This is legal private information that doesn't have to be disclosed. Encryption is about deliberately generating such legal private information, and then using it in agreed fashion.

 

These articles from bluejak's site will explain how it can be done. http://www.blakjak.demon.co.uk/brg_lnks.htm#genpwkl1

[bluejak]

Better is to look at General articles by Peter Winkler. Yes, they may look the same, but the Demon URL site never gets updated, and will disappear someday. http://blakjak.org is in a different place and is the real site.

[Trinidad]

I'm intrigued by this idea. What sort of things can you use as an encryption key? If it has to be based on the current hand I have no idea how you could do it, but if not, it is quite easy. For example, base it on the total number of tricks your side has taken in the session so far. If that sort of thing is not illegal, it should be.

A simple situation is in RKCB (or better in kickback):

You ask for the number of keycards and find that they are all there. Now you want to make a grand slam try by asking for specific kings. You can use the trump king as the key. Assuming spades are trump, the replies to 5NT could be:

6♣: ♣K, no ♠K or ♦K+♠K

6♦: ♦K, no ♠K, no ♦K or ♥K+♠K, no ♦K

6♥: ♥K, no♠K, no minor suit K or ♣+♠K, no red K

6♠: No side king

 

Rik

[Finch]

I'm intrigued by this idea. What sort of things can you use as an encryption key? If it has to be based on the current hand I have no idea how you could do it, but if not, it is quite easy. For example, base it on the total number of tricks your side has taken in the session so far. If that sort of thing is not illegal, it should be.

 

I don't think it's illegal as such, but I think you are obliged to tell me how many tricks your side has taken in the session so far.

More interesting is a key such as the parity of the first card played from dummy on the first board played against these particular opponents, which in principle is information they already have.

[nigel_k]

I like the ideas in the articles on Bluejak's site, the main one being that you can make a forcing raise of partner's suit showing one of the top two honours and then follow up by encrypting based on which member of the partnership has the ace and which has the king. This is something that can be established at a low level without too much disruption to system. The simplest way seems to be to just have two ways to raise, e.g. 1♣-P-2♣ is a club raise with one of the top two honours and 1♣-P-2♦ is a club raise with zero or two. This caters for the vast majority of hands.

 

But I don't see anything in the laws that says the key must be derived solely from hands played against the current opponents, and anything else must be disclosed. IMO you are required to disclose your implicit or explicit agreements. Obviously if you use something like your wife's birthday as the key then probably you have explicitly discussed the relevant information, or at least partner can infer it implicitly from your previous bidding and play. But in the case of a key that changes constantly, such as the number of tricks your side has taken in the session, I don't see that the value of the key itself is an undisclosed agreement. I'm not suggesting this ought to be legal or is even a remotely reasonable thing to do, just that it doesn't seem to actually be illegal.

[blackshoe]

The law, if I'm not mistaken, requires prior disclosure "in accordance with regulations" (paraphrased). What regulation requires disclosure of such keys? I don't think any RA has established such regs, have they?

[bluejak]

Suppose there were a regulation. Now, following the principle of Full Disclosure, I believe that anything based on some event in the past eg number of tricks or wife's birthday should be made disclosable. I believe such a regulation would say so.

 

One of the posts earlier got me to thinking. I play, as a few players do around here, that after RKCB the king ask [assuming spades as trumps] has responses 6♣ etc as showing either the king of clubs or the kings of diamonds and hearts. Of course it is assumed you can work out which. Surely this is encrypted?

[iviehoff]

I play, as a few players do around here, that after RKCB the king ask [assuming spades as trumps] has responses 6♣ etc as showing either the king of clubs or the kings of diamonds and hearts. Of course it is assumed you can work out which. Surely this is encrypted?

Sometimes one of the defenders, sometimes even both, will hold one of the kings and know what it means too, so it certainly isn't fully encrypted. In fact I wonder if it is encrypted at all unless you have specifically arranged it that you can surely tell.

[mjj29]

Sometimes one of the defenders, sometimes even both, will hold one of the kings and know what it means too, so it certainly isn't fully encrypted. In fact I wonder if it is encrypted at all unless you have specifically arranged it that you can surely tell.

Well, it would be foolish to ask if you couldn't...

[nigel_k]

Suppose there were a regulation. Now, following the principle of Full Disclosure, I believe that anything based on some event in the past eg number of tricks or wife's birthday should be made disclosable. I believe such a regulation would say so.

 

One of the posts earlier got me to thinking. I play, as a few players do around here, that after RKCB the king ask [assuming spades as trumps] has responses 6♣ etc as showing either the king of clubs or the kings of diamonds and hearts. Of course it is assumed you can work out which. Surely this is encrypted?

There is a distinction in that your choice of bid doesn't depend on a key which has been established earlier. You always bid 6♣ with the ♣K only or with both red kings, and not in any other case.

 

As an alternative, you could play that responder shows kings as above when they lack the trump ace, but when they have the trump ace they bid the suit above what they would normally bid, i.e. with the above holdings you would bid either 6♣ or 6♦ depending on whether you have the trump ace.

 

Both rely on partner working it out from their own holding. The difference is whether you have a pre-established key that changes how you bid with a given holding.

[Phil]

A simple situation is in RKCB (or better in kickback):

You ask for the number of keycards and find that they are all there. Now you want to make a grand slam try by asking for specific kings. You can use the trump king as the key. Assuming spades are trump, the replies to 5NT could be:

6♣: ♣K, no ♠K or ♦K+♠K

6♦: ♦K, no ♠K, no ♦K or ♥K+♠K, no ♦K

6♥: ♥K, no♠K, no minor suit K or ♣+♠K, no red K

6♠: No side king

 

Rik

This is the exact example I have seen of 'encrypted bidding'. As a practical matter, I don't this scheme is very useful, since the scope of when it helps is very limited.

 

OTOH, Winkler's articles have some very intriguing and compelling examples of crypto-bidding.

[BunnyGo]

Since it's in his book, I was wondering if it would be possible for BBO to allow a new method of table scoring: that of IMPs against par. I think this would be something I'd prefer since it would not only tell me what par was, but would provide scores for my table which didn't depend on 16 random BBO tables (which can produce wild scores). Is this possible in the next upgrade?

[f0rdy]

Since it's in his book, I was wondering if it would be possible for BBO to allow a new method of table scoring: that of IMPs against par. I think this would be something I'd prefer since it would not only tell me what par was, but would provide scores for my table which didn't depend on 16 random BBO tables (which can produce wild scores). Is this possible in the next upgrade?

 

But how are you going to decide the par? Double dummy results are no good unless you want a lot of the game hands flattened because the solver can make 6D in the 4-3 fit by knowing where all the queens are; obviously that would be the same for all the players, but would flatten all the comparisons; being in 3S+2 will no longer be a 10 IMP loss against bidding the game.

 

I agree that comparing against a small number of random results isn't great, but it's hard to see how you can do better with an automated system (assuming BBO does cross-imps, rather than Butler... it does at least do that, right...?)

[mgoetze]

I agree that comparing against a small number of random results isn't great, but it's hard to see how you can do better with an automated system

 

Compare against a large number of random results? ;)

[BunnyGo]

But how are you going to decide the par? Double dummy results are no good unless you want a lot of the game hands flattened because the solver can make 6D in the 4-3 fit by knowing where all the queens are; obviously that would be the same for all the players, but would flatten all the comparisons; being in 3S+2 will no longer be a 10 IMP loss against bidding the game.

 

I agree that comparing against a small number of random results isn't great, but it's hard to see how you can do better with an automated system (assuming BBO does cross-imps, rather than Butler... it does at least do that, right...?)

 

Yes, I want to compare against double dummy par results. There are some hands where this will lead to strange results (lose 11 IMPs because you were in the 95% 3nt and not the 2% slam which happens to work). In general, I think that comparing to par is more interesting (or at least something to try). Maybe you'll notice that you lose on average in part score battles...then you'll learn that you can push harder than you have been. It's of course not perfect, but I think if nothing else it is an interesting (and possibly illuminating) way of scoring.

[bluejak]

It sounds boring and of little interest to me. But if you want to suggest it, may I advise the BBO tournaments forum, or somewhere like that?