How many cards should be marked?

[fraac]

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.

[tewall]

Thank you. I thought so too.

[tewall]

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.

[plexiq]

"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".

[alphatmw]

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

[Voltaire]

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.

[paperjam]

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

[RonMexico]

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.

[lemming]

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...

[ratel]

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.