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"probabilistic" opening bids abstract musings

#1 User is offline   gombo121 

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Posted 2011-August-31, 14:06

While discussing building a system with a friend I arrived to a curious question: suppose I'd like to introduce an two-way opening 2, which promise
1) 11-15, 6+
2) 5-8, 5+, 20%(!)
but with a twist - second variant is used not each time when a suitable hand presents itself, but in only, say, 20% cases chosen completely at random.

Is there any general regulations against such agreements (besides it is being obviously brown sticker)? I feel that probably there are some, but cannot come up with any concrete example.

The second, somewhat related question - is it legal to have two separate bids that describe the same (or, may be, overlapping) type of hands with choice between them being random?
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#2 User is offline   ArtK78 

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Posted 2011-August-31, 14:25

I am sure it is not permitted, but I am not able to quote chapter and verse.

How would you insure that the 2 bid was made on 20% of the appropriate spade hands randomly? Would you roll a 5-sided die? Pull one of five perfectly equal balls (except that one was red, the others blue) out of a hat? In order to assure all involved that there was no UI being passed, would you use the selection method every time you open 2 whether or not the bid was being made based on hearts or spades? Even more - would you have to go through the selection process on every hand where you intend to pass so as to not convey UI? Clearly, the players cannot see the result of your method of making your random choice.

The concept is interesting in the abstract. If you think about how you would accomplish it in real life, it becomes comical.
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#3 User is offline   wyman 

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Posted 2011-August-31, 14:30

View PostArtK78, on 2011-August-31, 14:25, said:

The concept is interesting in the abstract. If you think about how you would accomplish it in real life, it becomes comical.


An idea that is often floated around the poker community is to use the position of the seconds hand of your watch as an RNG.
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#4 User is offline   G_R__E_G 

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Posted 2011-August-31, 14:31

It's part of the GCC that opening bids above 2 must show at least one known suit. Therefore doing something of this nature wouldn't be legal for that reason alone (along with at least a few other reasons I'm sure).

Edit - it has been a while since I've read the GCC but I was sure this was there. I just went and looked at it and now I don't see it??? Has it changed when I wasn't looking?
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#5 User is offline   gwnn 

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Posted 2011-August-31, 14:32

ArtK78: you could add together all the ranks of your cards and divide by 5. It would not be 20-20-20-20-20, but I'm sure it's not far either. furthermore, your disclosure would be immaculate. I'm not saying that it's workable or legal, just that it is theoretically possible. I'm sure hrothgar could come up with a much better approximation of 20% .
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#6 User is offline   ArtK78 

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Posted 2011-August-31, 14:40

View Postgwnn, on 2011-August-31, 14:32, said:

ArtK78: you could add together all the ranks of your cards and divide by 5. It would not be 20-20-20-20-20, but I'm sure it's not far either. furthermore, your disclosure would be immaculate. I'm not saying that it's workable or legal, just that it is theoretically possible. I'm sure hrothgar could come up with a much better approximation of 20% .

But the ranks of your cards is not independent from the requirements for the 2 opening.
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#7 User is online   hrothgar 

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Posted 2011-August-31, 14:51

I have long (and unsuccessfully) argued that psyches should be redefined in just such a manner...

FWIW, here's some content that I wrote a few years back

Mixed Strategies as applied to Bridge

The academic discipline of game theory differentiates between
“pure” strategies and “mixed” strategies. Pure strategies are
deterministic. Players choosing a pure strategy follow a predictable
course of action. In contrast, mixed strategies deliberately
incorporate random action. The simplest example of a mixed strategy
equilibrium is the Penny Matching game. Two players simultaneous
display a penny. If the two coins “match” (both coins are heads or
both coins are tails) then Player 1 keeps the two pennies. If the two
coins don't match then Player 2 keeps both pennies. The only
equilibrium strategy to this game is mixed. Each player should
randomly determine whether to display Heads or Tails using a 50/50
weighting scheme.

The concept of a mixed strategy can be applied to a number of
areas within bridge. The simplest and best know examples come from
declarer play and defense. Many well understood problems like
restricted choice make use of mixed strategies. For example, declarer
leads a low Diamond into D QJ9 and plays the Queen after LHO plays
low. RHO holds both the Ace and the King and needs to determine which
card to cover with. Restricted choice analysis presumes that the
defender is applying a mixed strategy will randomly chose to cover
with the Ace or the King, once again applying a 50/50 weighing scheme.
Mixed strategies can also be applied to the design of bidding
systems. Players applying a “pure” bidding strategy will always chose
the same bid bid with a given hand. In contrast, players employing a
mixed bidding strategy allow deliberate randomization. Consider the
following example taken from Bridge My Way by Zia Mahmood. You hold

S AQJ3
H K5
D 873
C A653

The auction starts

1H – 1S
3S - ???

and you need to chose a rebid. Zia advocates a bidding style in which
players should randomize between 4C and 4D cuebids. Zia never goes so
far as to discuss probabilities, but hypothetically he might chose a
4C cuebid 80% of the time and a 4D cuebid 20% of the time.
Alternatively, consider the following example: White versus Red
partner opens 1H in first seat promising 5+ Hearts and 10-15 HCP. RHO
passes. You hold:

S 742
H AK762
D 9732
C 4

I advocate a hypothetical “mixed” strategy in which players bidders

4H: 60% of the time
3NT: 20% of the time
2NT: 10% of the time
2D: 5% of the time
1S: 5% of the time

Players who adopt mixed bidding strategies allow for the use of
multiple bids to describe a single hand. As a consequence, many
responses could show radically different hand types. For example,
players adopting Zia's Sting Cue bid style need to describe their 4C
cue bids as either “First round control of Clubs or [rarely] no
control of clubs”. In an equivalent fashion, my partners would need
to describe my 3NT raise of a Precision 1H openings as either a strong
balanced hand willing to declare 3NT OR [rarely] a preemptive raise of
Hearts.

In turn, this brings us to the last major area in which mixed
strategies and bridge overlap: Regulatory structures. Few if any
Zonal authorities incorporate mixed bidding strategies into their
regulatory structures. Instead, regulators attempt to sidestep the
issue using the concept of a psychic call. Regulators and players
pretend that psychic calls are “deliberate and gross misstatements of
honor strength or suit length”. In actuality, so-called psychic calls
are a subset of a more complex meta-agreement involving mixed bidding
strategies. I argue that neither players nor regulators are served by
this pretense. Complete disclosure can never be achieved unless the
regulatory structure matches the actual strategies employed by
players.
Alderaan delenda est
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#8 User is offline   blackshoe 

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Posted 2011-August-31, 15:29

View PostG_R__E_G, on 2011-August-31, 14:31, said:

It's part of the GCC that opening bids above 2 must show at least one known suit. Therefore doing something of this nature wouldn't be legal for that reason alone (along with at least a few other reasons I'm sure).

Edit - it has been a while since I've read the GCC but I was sure this was there. I just went and looked at it and now I don't see it??? Has it changed when I wasn't looking?

Possibly. I don't know. What I know is seven of the nine regulations about opening bids deal with the two level and above:

Quote

3. TWO CLUBS ARTIFICIAL OPENING BID indicating one of: a) a strong hand. b) a three-suiter with a minimum of 10 HCP.
4. STRENGTH SHOWING OPENING AT THE TWO LEVEL OR HIGHER that asks for aces, kings, queens, singletons, voids or trump quality and responses thereto.
5. TWO DIAMOND ARTIFICIAL OPENING BID indicating one of: a) a strong hand. b) a three-suiter with a minimum of 10 HCP.
6. OPENING BID AT THE TWO LEVEL OR HIGHER indicating two known suits, a minimum of 10 HCP and at least 5–4 distribution in the suits.
7. OPENING NOTRUMP BID AT THE TWO LEVEL OR HIGHER indicating at least 5-4 distribution in the minors.
8. OPENING THREE NOTRUMP BID indicating one of a) a solid suit or b) a minor one-suiter.
9. OPENING FOUR-LEVEL BID transferring to a known suit.

As you found, none of these require "at least one known suit".

All that said, the OP didn't indicate where he is. It's possible the GCC is irrelevant to him.
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#9 User is offline   semeai 

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Posted 2011-August-31, 15:29

Let's start with an easier example. Maybe the bid is 2 showing 5-8 with 5+ spades but when you have that holding you only bid it 50% of the time and pass 50% of the time, choosing randomly. Other people may play 2 showing 5-8 with 5+ spades, only bidding it when they have that holding 50% of the time and passing 50% of the time, but deciding based on suit quality and other factors.

Surely when you have two bids that both describe your hand (here, pass and 2), you're free to decide on your own which to make as long as your disclosure of any partnership understandings is fine. This comes up all the time. Usually the answer isn't that you choose randomly, but if it is and you disclose properly, I don't see why that would be a problem. (Be warned, though, that I have no laws expertise.)

Often bids are just on a whim. If, say, my partner likes to upgrade unremarkable 14's to his 15-17 notrump "when he's feeling frisky" (and let's say that's 50% of the time), this is strikingly similar to him choosing randomly what to do with a 14. In fact, the former, even though much more common, is perhaps harder to properly disclose and not have UI from. I may be able to pick up on when my partner is feeling "frisky," whatever that means.

We are not simple automatons, and I'd argue that for even the most experienced, steady players (though for them would be less often), often enough the same hand in the same situation would be bid differently based on mood or lunch or the previous hand or whether a butterfly flapped through the neighboring room.

That all said, disclosure may be a problem. If you have a special method to choose pseudo-randomly, I suspect you should disclose it, and also make sure it's not one that your partner could crack. If you have no special method but it's "random, as decided by my gut sense of what's random", there's likely a problem with UI. Maybe you've recently had 5-8 with 5+ spades and you bid 2. Now it may be in your nature to make things "average out" and pass. This is a problem, as your partner has the past history, but your opponents do not. In other words, you'd better make sure your random variables for different instances of this bid are independent.

View Postgwnn, on 2011-August-31, 14:32, said:

ArtK78: you could add together all the ranks of your cards and divide by 5. It would not be 20-20-20-20-20, but I'm sure it's not far either. furthermore, your disclosure would be immaculate. I'm not saying that it's workable or legal, just that it is theoretically possible. I'm sure hrothgar could come up with a much better approximation of 20% .


Awesome. This would make the play of the hand hilarious if there was any guessing to be done with few cards remaining.

Would this be considered "encrypted," though, and thus disallowed? Your partner doesn't have the key, of course.

View PostArtK78, on 2011-August-31, 14:40, said:

But the ranks of your cards is not independent from the requirements for the 2 opening.


Gwnn didn't claim it was exact. In fact, he said "It would not be 20-20-20-20-20, but I'm sure it's not far either."
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#10 User is offline   bluejak 

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Posted 2011-August-31, 17:28

View Postgombo121, on 2011-August-31, 14:06, said:

While discussing building a system with a friend I arrived to a curious question: suppose I'd like to introduce an two-way opening 2, which promise
1) 11-15, 6+
2) 5-8, 5+, 20%(!)
but with a twist - second variant is used not each time when a suitable hand presents itself, but in only, say, 20% cases chosen completely at random.

Is there any general regulations against such agreements (besides it is being obviously brown sticker)? I feel that probably there are some, but cannot come up with any concrete example.

The second, somewhat related question - is it legal to have two separate bids that describe the same (or, may be, overlapping) type of hands with choice between them being random?

Are there general regulations? Presumably you mean Laws: no, there are not.

As for whether it is legal in a particular jurisdiction, there are lots of jurisdictions. Did you have anywhere in mind? Monaco? Thailand? Canada?

We ask that opening posts always say the jurisdiction [or "Online"] and quite a few discussions need to know that because of different regulations and different interpretations. This is one such question.
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#11 User is offline   aguahombre 

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Posted 2011-August-31, 18:42

View PostG_R__E_G, on 2011-August-31, 14:31, said:

It's part of the GCC that opening bids above 2 must show at least one known suit. Therefore doing something of this nature wouldn't be legal for that reason alone (along with at least a few other reasons I'm sure).

Edit - it has been a while since I've read the GCC but I was sure this was there. I just went and looked at it and now I don't see it??? Has it changed when I wasn't looking?

Can't imagine it was ever true. gambling 3NT? Opening Blackwood? Roman?

The GCC conventions allowed over opponents' 1NT opening do require 2D and higher to have a known suit. Maybe that is what you were thinking about.

This post has been edited by aguahombre: 2011-August-31, 19:36

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#12 User is offline   wank 

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Posted 2011-August-31, 22:09

as people seem to be ignoring the actual point of your post and quoting the regulations for baby level US tournaments, it would be perfectly legal to play as you suggest in a brown sticker event. of course opps might not believe you when you say you do it 20% of them time if they play against you a few times and you go on an unlikely run whereby each time you have the spade option, so it could lead to a little aggro.

and yes to play in the second way is legal. again people may start to believe it's not random and you'll get people whispering behind your back. i know a pair who say they played a random minor opening in a 5cM style and they're always slyly accused of being bent.
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#13 User is offline   Echognome 

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Posted 2011-August-31, 22:51

I guess the esoteric, but related question, is whether it should be a public randomization device, which is disclosed (which would be relevant in Gwnn's example) or a private randomization device? I think a randomization device can be crafted if one thought hard enough, as a few examples were mentioned above.
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#14 User is offline   aguahombre 

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Posted 2011-August-31, 22:56

View PostEchognome, on 2011-August-31, 22:51, said:

I guess the esoteric, but related question, is whether it should be a public randomization device, which is disclosed (which would be relevant in Gwnn's example) or a private randomization device? I think a randomization device can be crafted if one thought hard enough, as a few examples were mentioned above.

back to whether 40c3a should be placed more prominently since it mentions technique as well as memory.
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#15 User is offline   gombo121 

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Posted 2011-August-31, 23:38

I'm sorry I did not clarified the jurisdiction point. I understand that in a generally restrictive environment like GCC it does not stand a chance. But I'm not really going to try this concept in practice (at least, yet) and my actual jurisdiction (Russia) tends to be very permissive, so I'm interested in regulations (or, may be unwritten consensus) at international level concerning events that generally allow brown sticker conventions.

Concerning practical realization of the RNG, there is a very simple method - shuffle your hand before you look at it and then interpret red cards as zeros and black cards as ones - you get 13 bits of randomness, which should be enough for any practical purpose!
(OK, it won't work in online bridge, but then you probably can use RNG of your PC directly).
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#16 User is offline   helene_t 

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Posted 2011-September-01, 02:10

The question is not if a BSC is a allowed under a particular regulation. OP acknowledged that it is a BSC and therefore disallowed under most regulations.

The question is if mixed strategies are allowed.

I haven't been able to find anything on google so I would expect they are. Also, when watching certain expert players on vugraph, they will open "psychic" 1NT in 3rd seat so often that it isn't a psyche and can only be explained as a mixed strategy. Other baby psyches, such as 1-(x)-1), are so frequent in some partnerships that they are not psyches.
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#17 User is offline   semeai 

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Posted 2011-September-01, 06:56

View Postgombo121, on 2011-August-31, 23:38, said:

Concerning practical realization of the RNG, there is a very simple method - shuffle your hand before you look at it and then interpret red cards as zeros and black cards as ones - you get 13 bits of randomness, which should be enough for any practical purpose!


This is great, as it sends no other signal about your hand and uses no (possibly illegal) outside aid.

In fact, it gives you one of 13 factorial possibilities, using any absolute ordering of the cards. That's more than 32 bits.

To get 50%, note two cards from your hand, shuffle your hand, and see which is first. To get 20%, note three cards from your hand, shuffle your hand, and if they appear in the order 123 shuffle again, and if they appear in the order 321, take your 20% action.

Added: Maybe you don't want to be seen shuffling your cards more than the one initial time. In that case, do it once, and look at the first two cards for 50% or the first three for 20%. If the first three are in the order 123, look at the next three for your "second shuffle", and so on (this doesn't give exacty 20% as you have only four chances not to get 123).

Added: To get exactly 20%, look at the first five cards and check whether the highest of them in your absolute order is first.
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#18 User is offline   gwnn 

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Posted 2011-September-01, 07:00

That is a nice method, but I'm afraid it is not legal to base your system on such ideas. Your partner can not disclose this method in any satisfactory manner.
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#19 User is offline   semeai 

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Posted 2011-September-01, 07:17

View Postgwnn, on 2011-September-01, 07:00, said:

That is a nice method, but I'm afraid it is not legal to base your system on such ideas. Your partner can not disclose this method in any satisfactory manner.


Why? He just tells them exactly what you do. The result isn't knowable to your partner or opponents, but so what? Whether you're feeling frisky today is also perhaps not knowable, but it's allowed to base your actions on "whether I feel like taking a light action today."
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#20 User is offline   mgoetze 

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Posted 2011-September-01, 09:44

Let's say someone were playing a method with several potentially overlapping opening bids, say

1NT: 15-17 balanced
1: 11-21, 5+ spades
1: 11-21, 5+ hearts
1: 11-21, 3+ diamonds
1: 11-21, 3+ clubs

Now he might open 2344 13-counts 1 60% of the time and 1 40% of the time. He might claim that there is some system behind this, or that he does it absolutely randomly. Well, does it matter? Can you tell the difference? (Cf. Rosenberg, M.: "Bridge, Zia ... and me", p. 43)

Or he might open a 3532 15-count sometimes 1NT and sometimes 1. Does it really matter if it is random, semirandom or completely deterministic which of these hands he chooses which opening bid with?
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