Out of Sorts

[barmar]

I would agree. However I would also say that even a large amount of shuffling is not enough to prevent the next player from getting some information about the play of the hand.

One of the players in our club does 5-10 riffle shuffles before putting them back in the board. I've always found it annoying that he takes so long, it seemed like overkill, but it sounds like it really is necessary. Actually, I suspect that just a couple of riffles would break up most of the sequences that you noticed, so there's a happy medium. I think most people just do an overhand shuffle, which doesn't break up sequences so much.

 

In reality, I think most people are just concerned about the cases where the information gleaned from the order of the cards is blatant. When you receive a hand that's entirely sorted, and has 9-11 HCP, practically anyone can guess that the hand was a pass-out. If it's mostly sorted, then it was an early claim.

[campboy]

It doesn't arise from inspecting the faces of the cards. It arises from inspecting the order of the cards, which is quite different and is not something many people do.

[Cyberyeti]

Now, I am not arguing it should be authorised. I am arguing that it is under the Laws. The main point of this thread is that most people are blissfully unaware just how much information is available from the order of the cards, and a thorough shuffle is needed at the previous table. Far more than everyone gives.

I wish I could think fast enough at the table to deliberately order my cards in such a way that they would mislead the recipient before putting them away. I know it's illegal but if I suspected the person getting a board next was doing this ...

[barmar]

The main point of this thread is that most people are blissfully unaware just how much information is available from the order of the cards, and a thorough shuffle is needed at the previous table. Far more than everyone gives.

It doesn't bother me. I suspect it's much less information than is noticed subconsciously from mannerisms. Even given the results of your little experiment, I feel that predicting significant information about the hand is comparable to using the old adage "Red sky at night, sailor's delight; red sky at morning, sailors take warning" as a weather forecasting system.

 

In important contests, the problem could be avoided totally by giving each table their own set of boards. This is routinely done in the late rounds of team events, I'm not sure how practical it is in pair events.

[lamford]

so there's a happy medium.

She would be if she could work out exactly what happened at the previous table.

[Vampyr]

Wow, that's the best palindrome I've ever seen.

 

Anyone know the word for fear of palindromes?

 

 

aibohphobia

 

Edited August 21, 2012 by barmar
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[lamford]

Even given the results of your little experiment, I feel that predicting significant information about the hand is comparable to using the old adage "Red sky at night, sailor's delight; red sky at morning, sailors take warning" as a weather forecasting system.

I think you are shooting yourself in the foot by using this metaphor. The point is that the correlation between future weather and the sky is quite high. From one source:

 

Red sky at night, sailors delight

When we see a red sky at night, this means that the setting sun is sending its light through a high concentration of dust particles. This usually indicates high pressure and stable air coming in from the west. Basically good weather will follow.

 

Red sky in morning, sailor’s warning

A red sunrise reflects the dust particles of a system that has just passed from the west. This indicates that a storm system may be moving to the east. If the morning sky is a deep fiery red, it means a high water content in the atmosphere. So, rain is on its way.

 

So the sky is quite a good forecaster of weather, and the order in which the cards appear is quite a good forecaster of the success or otherwise of those pesky finesses. UI or not.

[gnasher]

I think you are shooting yourself in the foot by using this metaphor.

If off-topic nitpicking is allowed, can I point out that it was a simile or possibly an analogy, but definitely not a metaphor?

[gordontd]

Excellent idea. However, I will then be at a disadvantage over those that do not do this,

Only over those who not only don't do this (shuffling before inspecting), but also who make the sorts of deductions suggested by you in this thread. In my experience, that would be virtually no-one.

[barmar]

I would agree. However I would also say that even a large amount of shuffling is not enough to prevent the next player from getting some information about the play of the hand. I did some tests at home, and found that I guessed some information about the last hand 50% of the time, shuffling much as people do after a hand is played. The most common information I obtained was that if three cards of the same suit were consecutive after shuffling, they were trumps over half the time. Declarers play three consecutive rounds of trumps far more often than three consecutive rounds of a side suit. The second most common piece of information related to two consecutive honour cards, the smaller of which was lower in the slot. Over 90% of the time this meant that the first honour did not lose the trick to the person over the honour. Of course, sometimes they came together because of the shuffle, but far more often they were not separated by it.

 

Is all this information authorised? If not, then the TD should be called every other hand, and the board is usually unplayable.

I'm a little suspicious of your tests. I've been reading the book "Thinking Fast and Slow", and it has a chapter on the Law of Small Numbers. Basically, what it points out is that most people's intuitions about statistics and probability are wrong, including most research scientists. In particular, it's very easy to get misleading results with small samples. How large was the test you performed? The example given in the book is that the counties with the highest rates of cancer in the US are mostly rural, but so are the counties with the lowest rates of cancer; most of these places are not actually cancer-prone or cancer-averse, it's just that rural areas are sparsely populated, so sampling error has a larger effect.

 

Also, how rigorous was it? Another problem people run into is "confirmation bias" -- we tend to notice examples that match our expectations, and discount the one that refute it as well. So unless you were systematic in performing the test, you may have succumbed to this.

 

Here's another possible flaw in the test. If the hand you were looking at happened to be declarer (or dummy after a transfer auction), trumps was probably its longest suit. So after even a perfect shuffle, the cards in the trump suit are more likely to be clumped together simply because there are more of them.

[bluejak]

Only over those who not only don't do this (shuffling before inspecting), but also who make the sorts of deductions suggested by you in this thread. In my experience, that would be virtually no-one.

I wonder. Don't you think there are a lot of people out there who use all sorts of shady practices to acquire information, and keep quiet about it?

[lamford]

How large was the test you performed?

Quite small; around 10 hands only. It was tedious and unenjoyable. But I have performed similar (much larger) tests on recorded shoes simulating blackjack in casinos, and do know that the information gleaned from a shuffle is significant. I would estimate that the information is worth about 2 IMPs a board in bridge, but that is a pure guess.

[lamford]

In my experience, that would be virtually no-one.

But that is only because they unaware of how to do it. After a few training sessions from me ... Perhaps we can arrange a seminar at YC?

[barmar]

It sounds like card counting at Blackjack -- everyone understands in theory how valuable it can be, and it doesn't even seem that hard, but unless you're really determined it's a PITA to do in practice.

[gnasher]

I wonder. Don't you think there are a lot of people out there who use all sorts of shady practices to acquire information, and keep quiet about it?

I don't. I think that the number of such people is tiny.

[gwnn]

Quite small; around 10 hands only. It was tedious and unenjoyable. But I have performed similar (much larger) tests on recorded shoes simulating blackjack in casinos, and do know that the information gleaned from a shuffle is significant. I would estimate that the information is worth about 2 IMPs a board in bridge, but that is a pure guess.

With 2 IMP's/board you could make almost any team of 6 people able to solve BM2000 level 3 to win the Bermuda Bowl. And all this because on some hands (say, 25%) they know to some degree of confidence (say 50%) what the trump suit was in the previous table (OK and some tiny hints about the play to much smaller degrees of confidence)?

[gwnn]

I think even knowing to 100% degree of confidence the cobtract and result from the other table would be a largely useless piece of information (as long as you do not know the opening lead, for instance).

[barmar]

Knowing the contract at the other table is only helpful if you would not have gotten to the same contract on your own, and if the other table was actually in the best contract.

[lamford]

Knowing the contract at the other table is only helpful if you would not have gotten to the same contract on your own, and if the other table was actually in the best contract.

Would you care to play a match where I know the contract at the other table but you don't? You can choose the stake.

[lamford]

If off-topic nitpicking is allowed, can I point out that it was a simile or possibly an analogy, but definitely not a metaphor?

I think it's just a saying.

[barmar]

Would you care to play a match where I know the contract at the other table but you don't? You can choose the stake.

No, but I still think 2 IMPs/board is a significant overestimate.

[lamford]

No, but I still think 2 IMPs/board is a significant overestimate.

It is all of the information that is worth an estimated 2 IMPs. And only when the board has been previously played. Say I pick up: ♦4 ♣K ♥2 ♣9 ♠A ♠K ♠J ♦3 ♣A ♠8 ♦Q ♦J ♣2. I would think as follows (were I so inclined):

a) That spade order AKJ in sequence is interesting. I think they were probably trumps, and declarer did not finesse the queen. Perhaps partner has it, or we have 9, and the singleton queen fell, which is why three rounds were played. If we agree spades, I will not bother asking for the queen of trumps.

b) The cards were probably shuffled quickly at the other table, as I would have expected the trumps to have been played earlier than that.

c) The club king and ace are separated. They might have been shuffled apart, but more likely they were not played on consecutive tricks. They probably were not trumps. Alternatively clubs were led, and we won with one of those, and the other was played later.

d) the spade 8 probably ruffed something, which is why it is not next to its other colleagues.

e) If partner has the ♦A, then the diamond finesse is probably right, as the ♦ Q was followed by the J.

f) based on the above I would bid a 25% slam and expect to make it.

 

In all those cases, the possibility is that the cards were shuffled to that sequence. But that will occur much less often than two or three cards having been played in that order before.

 

Perhaps, I can spot you 2 IMPs per board, only on those boards which are played first at the other table. We choose our partners. My compass-mate's cards are shuffled just into three parts and interchanged. Yours are put into a machine. £10 an IMP at TGRs?

[lamford]

I don't. I think that the number of such people is tiny.

How can you conclude this? How can you know what information others draw from the order of the cards they pick up? And how do you know how many of them note the significant features of the hand before sorting it, as it take only a few seconds?

[gordontd]

how do you know how many of them note the significant features of the hand before sorting it, as it take only a few seconds?

I think it would be quite noticeable if a player took a few seconds looking at their hand before starting to sort it. I would suggest most players start to sort before getting sight of the whole hand, and that they start on that a fraction of a second after turning their cards towards them. In that context, a few seconds looking at the whole hand would be a conspicuously long time.

[iviehoff]

What we conclude from this is that a requirement to sort the hand into suits at the end of play would be a much better rule. Moreover it would be timesaving, since you will do just the same amount of sorting if you receive your hand sorted and sort it at the end. I believe the only criticism of such a rule is that it is difficult for a minority to comply, but surely they can get someone to help.