How many cards should be marked?
 

One of the ruses for cheating one sees on T.V. is to mark the cards with something you can see with your glasses. This made me think of an interesting question. Suppose you are able to mark cards, and all you know is the card is marked or not marked (that is, the marks are all identical, so all you know is the card has been marked; there aren't different marks for different cards).

In a hold 'em game (or any other, but this was the first one I thought of), what would be the optimal number of cards to mark?

Re: How many cards should be marked?
 

read:
Poker Protection - Cheating and the World of Poker by Steve Forte
every person who plays live should read it.

Re: How many cards should be marked?
 

Did he have anything to say about my theoretical question?

Re: How many cards should be marked?
 

so are you basically trying to cheat?
anyways, mark key cards... A,K,Q,J, all with different marks per card(aces = mark in spot xyz)

Re: How many cards should be marked?
 

[ QUOTE ]
so are you basically trying to cheat?

[/ QUOTE ]

No, I'm just a math buff.

Re: How many cards should be marked?
 

[ QUOTE ]
anyways, mark key cards... A,K,Q,J, all with different marks per card(aces = mark in spot xyz)

[/ QUOTE ]

My question is assuming all marks are identical, so you can't mark differently. Obviously, if you marked cards differently, then you'd want to mark as many as possible. However, if all marks are the same, then you reach a point where marking more cards becomes counter-productive. When do you reach that point?

Re: How many cards should be marked?
 

[ QUOTE ]
[ QUOTE ]
anyways, mark key cards... A,K,Q,J, all with different marks per card(aces = mark in spot xyz)

[/ QUOTE ]

My question is assuming all marks are identical, so you can't mark differently. Obviously, if you marked cards differently, then you'd want to mark as many as possible. However, if all marks are the same, then you reach a point where marking more cards becomes counter-productive. When do you reach that point?

[/ QUOTE ]

they were talking about blackjack. that should clear it up.

Re: How many cards should be marked?
 

You can't see any of the cards to come because of the burn card, so my intial reaction would be to just mark the four aces. Aces serve as top pair or the top kicker often enough to make this a pretty useful piece of information that you'll see with some regularity.

The other thing I was thinking was maybe marking the 10s and 5s, since you can't make a straight without them, but I don't think that situation would come up quite enough. For similar reasons you could mark all 13 of a suit.

Even marking ALL of the red cards (or black cards, or any two suit combinations) could potentially give you some advantageous information - you can rule out flush draws in some instances. So, I think marking up to 26 cards would still be useful.

If you're marking more than that, then it's counter productive - if you want to mark three suits, for example, you should mark them by leaving them unmarked (and marking the leftover suit).

[This is trying the question how many would be optimal as the OP put it, assuming identical card markings]

Re: How many cards should be marked?
 

This is an extremely complex question, as it goes to the a tradeoff between your prior information from the markings and the information opponent will give you by her particular betting patterns as they interact with the markings. Say you mark aces, sevens, and deuces. Solid opponent raises UTG = AA (6/66 hands possible with the markings). Solid opponent limps after two limpers = 77, 22, A7s, A2s (20/66). Combine that with known cards and reaction to the flop, and you get pretty good info.

On the other hand, marking cards which tend to be played in similar ways would benefit you when you are to act before opponent. Marking aces, kings, and queens would let you know with 100% certainty that a player behind you has a strong to monster hand. Very good. But if two marked cards are to open in front of you, you will get minimal additional information from the expected open-raise.

There is clearly no straighforward mathematical answer.

Re: How many cards should be marked?
 

[ QUOTE ]
This is an extremely complex question, as it goes to the a tradeoff between your prior information from the markings and the information opponent will give you by her particular betting patterns as they interact with the markings.

[/ QUOTE ]

I also think there is lot more to the question than posted. If you have information regarding opponent's tendencies, frequencies, ranges, etc., then you're in far better shape to determine an optimal number of cards to mark.

Re: How many cards should be marked?
 

But with no other information and ignoring that some information pays more than others (dependent on the players, so ignore it), what's the most information you could gain from marking cards? It's a lovely question.

Re: How many cards should be marked?
 

Thank you. I thought so too.

Re: How many cards should be marked?
 

Nice post.

Marking A's, 2's and 7's is a very interesting idea. I had just thought in terms of marking the high cards.

The point about whether you are acting before or after is a good one as well. You could take that into account and try to decide which information is more valuable. That is, if you would mark one way acting in early position, and another in late, perhaps it would be better to mark the way that's advantageous in early position, since you may gain more that way.

Re: How many cards should be marked?
 

"What's the most information you could gain from marking cards?"

If we consider just marked hole cards, the maximum average information gain by marking is 1.58 Bit (per opponent?). ie: Opponent will have either 0, 1 or 2 marked hole cards.

Average information gain is max'ed if the 3 "marked-states" are equally likely postflop. So, you would definitely have to choose your markings depending on the chance that a given card "sees the flop".

Re: How many cards should be marked?
 

very interesting question. i'm tempted to just mark aces and kings.

Re: How many cards should be marked?
 

Great question!

Thinking aloud here... If you mark aces and kings (as alphatmw suggests) whenever you see somebody with two marked cards, it's 16/28 = 57% that they have AK (14.3% that it's AK suited). If you have an under pocket pair I would think you could safely fold preflop in limit if it's a raise cold to you, but in NL you might be able to win a lot of money the approximately 12% of the time you flop a set.

If your opponent has one marked card the best he can have is AQ or KQ... How valuable is that knowledge? I don't know.

This is a very difficult question, the more I think about it. Marking sevens or deuces does not seem to me to be a good idea since you will not be up against sevens or deuces very often. If you are going to mark just one card rank, you would want to mark aces, I think.

Here's an idea. If you mark all A's, K's and Q's, you will know in many situations that your opponent is on a limb or is likely to have a hand. If you get raised and it's heads up and your opponent has no marked cards you can get a valuable read on his hand and take advantage of it if big cards flop, or if he has one marked card and rags flop...

There is so much to think about. I think I'll just wait and see of some of our resident geniuses will chime in on this. There might be a clear answer, or a fairly clear answer in limit or NL.

Re: How many cards should be marked?
 

mark all deuces through sevens or nines - you can accurately gauge an opponent's kicker, as well as gauge your relative strength preflop and on any given flop, since, for example, on an AJ10 flop, if you opponent has 2 marked cards and bets, you can effectively steal the pot

Re: How many cards should be marked?
 

In fast structure tournament play, I think you'd gain a huge advantage in marking all face cards and aces. I say this because of the implications in blind stealing. You could actually steal very safely (and resteal for that matter) on the short stack for a long time, not to mention the edge you'd still have deep or semi-deep. In other words, the number of cards you'd mark in different games could be totally different. Also, I'm assuming you can see markings on all hole cards at table preflop.

Re: How many cards should be marked?
 

Hm, as to my home-games I'm thinking I would mark Aces, Kings and Queens, 12 cards...

Would give me some reads on whether a guy is holding a premium Hand (only 2 marginal hands included there: AQo, KQo) or a lower PP when being a nit and raising PF... Also allows me to be calculate implied odds with low PPs etc against a nit (who's not raising KQo in position e.g.)!

At least in our homegames, this would be a pretty huge advantage imo...

Re: How many cards should be marked?
 

People who have to mark cards to win are pathetic. You'll be lucky if you don't get beat down like a dog after a real player catches you at it.

Re: How many cards should be marked?
 

As it so happens, there are plenty of cards that are already virtually marked!

For example, lets say you are in a 10 handed Hold'em game and preflop, everybody folds to you in the SB. You can now reason that: since none of those 8 players that folded would fold AA, KK or AK, and since these are the only hands where--both--cards are either an Ace or King, then at least one of the cards folded in each hand is neither an Ace nor a King i.e. 8 of those cards are virtually marked as being neither an Ace nor a King. You don't know which of the 2 cards folded by each player is virtually marked as such, but that doesn't matter. This information is quite useable.

This means, as far as the chances of flopping an Ace (or King) is concerned, you can assume there are 42 unseen cards rather than 50 when you compute the chances of an Ace (or a King) being flopped.

This tips the odds significantly in your favor of flopping an Ace (or King) if that is what you need to hit your hand. Alternatively, it could also tip the odds significantly in your disfavor if an Ace (or a King) is NOT what you want to be flopped.

An example where this idea can be applied are for the infamous Ace Magnets: KK. Now you know it isn't just your paranoia!

A few additional notes:

1) This type of argument can be extended to include Queens in loose or short handed games i.e. nobody would fold AA/KK/QQ/AK/AQ/KQ, etc. In other words, in most of the games most people actually play in.

2)It can also be applied to those situations where players folded after you if you accept that no one acting after you would fold AA, KK or AK e.g. if you were seated in MP or whatever and a couple of players folded after you acted, then you could include them in your argument too and not just the players that folded before you, etc.

3) This preflop observation can also be applied in later streets. Wherever estimating the chances of an Ace or King coming up on the board or being in an opponents hand is concerned.

Re: How many cards should be marked?
 

[ QUOTE ]
People who have to mark cards to win are pathetic. You'll be lucky if you don't get beat down like a dog after a real player catches you at it.

[/ QUOTE ]

You do realize this is the poker theory thread right? OP has a good question here.

Back on topic: What about marking kings and queens only? That would be pretty helpful to Ace-rag hands, and underpairs to a degree.

Re: How many cards should be marked?
 

[ QUOTE ]
As it so happens, there are plenty of cards that are already virtually marked!

For example, lets say you are in a 10 handed Hold'em game and preflop, everybody folds to you in the SB. You can now reason that: since none of those 8 players that folded would fold AA, KK or AK, and since these are the only hands where--both--cards are either an Ace or King, then at least one of the cards folded in each hand is neither an Ace nor a King i.e. 8 of those cards are virtually marked as being neither an Ace nor a King. You don't know which of the 2 cards folded by each player is virtually marked as such, but that doesn't matter. This information is quite useable.

This means, as far as the chances of flopping an Ace (or King) is concerned, you can assume there are 42 unseen cards rather than 50 when you compute the chances of an Ace (or a King) being flopped.

This tips the odds significantly in your favor of flopping an Ace (or King) if that is what you need to hit your hand. Alternatively, it could also tip the odds significantly in your disfavor if an Ace (or a King) is NOT what you want to be flopped.

An example where this idea can be applied are for the infamous Ace Magnets: KK. Now you know it isn't just your paranoia!

A few additional notes:

1) This type of argument can be extended to include Queens in loose or short handed games i.e. nobody would fold AA/KK/QQ/AK/AQ/KQ, etc. In other words, in most of the games most people actually play in.

2)It can also be applied to those situations where players folded after you if you accept that no one acting after you would fold AA, KK or AK e.g. if you were seated in MP or whatever and a couple of players folded after you acted, then you could include them in your argument too and not just the players that folded before you, etc.

3) This preflop observation can also be applied in later streets. Wherever estimating the chances of an Ace or King coming up on the board or being in an opponents hand is concerned.

[/ QUOTE ]yes because all these players never fold hands like K2o and A5o from late and middle position.

Re: How many cards should be marked?
 

Assuming I'm a good player in a tough game, I'd consider marking these cards:

AhKhQhJh
AdKdQd
AsKs
Ac

Marking this way yields a lot of information, some of which is quite subtle.

Re: How many cards should be marked?
 

Mark all aces and kings. Knowing you are against AA, KK or AK can make some hard folds real easy. Knowing you aren't against AA, KK or AK, can help in some situations.

Re: How many cards should be marked?
 

people saying just mark Aces, or kings, or queens, clearly have no idea of the problem. please don't say that in future replies.


It seems to me that the analysis should be done from the reverse - finding what situations would be the most profitable to know your opponent's cards.

I already have an idea of when my opponent has a premium preflop hand - chances are, they are raising with it. Fundamentally, whether they precisely have AA, or KK, or QQ, or JJ, is not important. They are likely to have a strong hand.


It seems to me that a great opportunity to make additional profit is when the big bets are made: at the river. Thus, it seems to me to make sense to mark cards that are drawing hands, and given the limitation of only one mark being used, there are two viable options:

*marking by suits
or
*marking "mid-ranking" cards - (eg, 7-T)

Re: How many cards should be marked?
 

[ QUOTE ]
Assuming I'm a good player in a tough game, I'd consider marking these cards:

AhKhQhJh
AdKdQd
AsKs
Ac

Marking this way yields a lot of information, some of which is quite subtle.

[/ QUOTE ]

Pls explain

[img]/images/graemlins/cool.gif[/img]

Re: How many cards should be marked?
 

This logic can also be extended to Q's, J's, T's, 9's, 8's, 7's, 6's, 5's, 4's, 3's and 2's, since nobody will fold any pair of any of the above hands either. It works fine for all other cards tho.

Re: How many cards should be marked?
 

Do you have a list of what hands your opponents tend to play? If so, it should be quite easy to find the set of marks that makes the sets of hands containing 0, 1, and 2 marked cards most equal in size. Against opponents who play any two cards the same way, marking 26 is best (giving you ~1/4, 1/2, 1/4 chance of seeing 0, 1, or 2 marks.)

Against real-life opponents.... my first thought is to mark face cards but not aces:

No marks, raise: AA/TT/99 (more pockets perhaps)
No marks, limp: Axs or small pocket
One mark, raise: AK/AQ (AJ?)
One mark, limp: AJ? JTs?
Two marks, raise: KK/QQ/JJ (KQs in late position?)
Two marks, limp: KQ/KJ/QJ.