[lamford]

gnasher, on 2012-August-21, 02:33, said:

If you really think you risk obtaining useful information from the sequence of the cards your pick up, why not just give them a thorough shuffle before you look at them?

Excellent idea. However, I will then be at a disadvantage over those that do not do this, as they are not required to by Law. Perhaps we should change Law 7B1 to read.
1. Each player takes a hand from the pocket corresponding to his compass position. Before inspecting the faces, each hand is thoroughly shuffled both by an opponent and by the player. There is a cut if either opponent requests it.

[gnasher]

lamford, on 2012-August-21, 02:56, said:

Excellent idea. However, I will then be at a disadvantage over those that do not do this, as they are not required to by Law. Perhaps we should change Law 7B1 to read.
1. Each player takes a hand from the pocket corresponding to his compass position. Before inspecting the faces, each hand is thoroughly shuffled both by an opponent and by the player. There is a cut if either opponent requests it.

We don't need to. All we have to do is read 16C1, including the word "as".

[lamford]

gnasher, on 2012-August-21, 03:27, said:

We don't need to. All we have to do is read 16C1, including the word "as".

We can use 16C1 only for information that is unauthorised. If the hand was shuffled at another table, and the information is gleaned from inspecting the faces of the cards, then it is surely authorised, and 16C1 does not help us. Do you not think that the information is "arising from the legal procedures authorized in these laws"?

[gnasher]

lamford, on 2012-August-21, 03:33, said:

We can use 16C1 only for information that is unauthorised. If the hand was shuffled at another table, and the information is gleaned from inspecting the faces of the cards, then it is surely authorised, and 16C1 does not help us. Do you not think that the information is "arising from the legal procedures authorized in these laws"?

No, I think it's something that may happen when you follow a legal procedure, but it doesn't arise from that procedure. The procedure is for you to inspect the faces of the cards, not to note their order.

It's comparable to the UI one would receive if, whilst a board was being placed on the table, a traveller fell out and landed face up. Putting the board on the table is proper procedure; any information accidentally received from seeing the traveller is UI; intentionally reading the traveller is cheating.

[lamford]

gnasher, on 2012-August-21, 04:24, said:

No, I think it's something that may happen when you follow a legal procedure, but it doesn't arise from that procedure. The procedure is for you to inspect the faces of the cards, not to note their order.

It's comparable to the UI one would receive if, whilst a board was being placed on the table, a traveller fell out and landed face up. Putting the board on the table is proper procedure; any information accidentally received from seeing the traveller is UI; intentionally reading the traveller is cheating.

The traveller falling out is not the lawful procedure, however. One would not say "the information arose from the board being put on the table". One would say "the information arose from the traveller falling out." If the procedure was to take out the traveller and look at it (as it was for one board of the Woodberry Xmas Social), then the information would be authorised. The shuffling at the other table is the lawful procedure. The information arises directly from the shuffle at the other table, and from the inspecting of the cards. The order in which the cards appear comes from the combination of the play at the other table and the shuffle.

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.

[barmar]

lamford, on 2012-August-21, 02:20, said:

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]

lamford, on 2012-August-21, 04:50, said:

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]

lamford, on 2012-August-21, 04:50, said:

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]

barmar, on 2012-August-21, 08:49, said:

so there's a happy medium.

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

[Vampyr]

semeai, on 2012-August-17, 20:50, said:

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

Anyone know the word for fear of palindromes?

Spoiler

aibohphobia

This post has been edited by barmar: 2012-August-21, 15:13
Reason for edit: Use the forum's built-in spoiler feature

[lamford]

barmar, on 2012-August-21, 09:44, said:

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]

lamford, on 2012-August-21, 18:16, said:

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]

lamford, on 2012-August-21, 02:56, said:

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]

lamford, on 2012-August-21, 02:20, said:

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]

gordontd, on 2012-August-22, 02:11, said:

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]

barmar, on 2012-August-22, 04:47, said:

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]

gordontd, on 2012-August-22, 02:11, said:

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]

bluejak, on 2012-August-22, 09:45, said:

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.