How would a live poker tournament or cash game prevent me from marking cards using invisible ink or dust, then using custom-made glasses to see my markings when others get those marked cards in subsequent hands?

  • i would say not so much that they would prevent you, but they aren't blind and if they detect that you are doing it you will be in big trouble.
    – user1934
    Feb 6, 2017 at 17:00
  • 2
    This is predicated on your "invisible" ink really being only visible to you: nytimes.com/2014/08/23/nyregion/…. Feb 7, 2017 at 15:50

3 Answers 3


At a casino, it would be difficult to mark the decks without being seen. In addition, the decks get swapped every few hands, so you would have to mark multiple decks, which increases your likelihood of getting caught.

If you are talking about a private home game, the glasses and your actions would raise suspicions, especially if you won regularly with junk hands, or were the big winner.

  • Why would you have to swap the decks? suppose you had a bit of invisible ink on your finger. each time you are dealt two cards, you are touching the cards with your hands, and dab a bit of the ink in a certain way, depending on the value of each card. now when other players get those same cards, you already have illicitly gained some extra information.
    – user1934
    Feb 6, 2017 at 16:56
  • I am using the app on my phone, and misread the question, I thought it said that he would be providing the marked cards, as opposed to being the one doing the marking.
    – Herb
    Feb 6, 2017 at 19:25
  • I still thought it was a good answer and gave you the +1
    – paparazzo
    Feb 6, 2017 at 22:50

There would be

  • the ink or dust
  • the act of marking the cards
  • the custom glasses
  • inspecting the cards
  • new decks
  • dealers and staff trained at detecting
  • players detecting
  • surveillance cameras
  • your actions

In many states you would be breaking the law. In Vegas it would be a felony.

Pretty sure you have not broken poker.


Call me cynical, you could get away with it.

I am constantly amazed by how comfortable and confident that poker players are by their faith in the security systems they believe the casinos have to protect them. I kind of think that it has something to do with the addictive aspect of the game that puts many players in denial about a lot of things, the security of the game perhaps one of the minor things.

Ink and glasses are a little sloppy. You will be in possession of the evidence if caught. You really do not even need to mark the cards. Most are already marked in some intentional or unintentional way. Ace of spades and King of clubs almost always sit on the top or the bottom of a made up deck, tending to give them a little more warp then the rest of the cards. Many card rooms contrary to Herbs contention that the cards are changed every few minutes, leave the same deck in for days, weeks even months. Many card rooms replace a single card in a deck when one is defective or breaks. Kem cards, the most common used cards, have very bad quality control between batches. The cards will vary in thickness, width and height, ink shades and corner radius, all of which make them essentially readable as marked cards. This is a wide spread problem, most card rooms do not care about this particular part of game security enough to spend the extra money to keep the cards in the game in good shape.

A Little Bonus: How to spot a painted deck. Marked decks are typically marked in a pattern. As an example bicycle decks are marked by modifying each spoke of the bicycle wheel on a card back. To spot the marking you look at the deck like you look at a pad of paper you drew a cartoon on. The markings will animate and even the most discrete markings jump right out at you. (somewhere I have a painted deck, I will see if I can get the effect to show up in a video).

  • I've always wondered about these "bicycle wheel" marks. Haven't seen one personally but wouldn't it be insanely difficult to read a mark from across the poker table? May get a read off left and right, but i still feel you have to scrutinize your villain's hole cards, which is obvious and weird. Board cards have burned cards on them, so that wouldn't work too well also.
    – sakon
    Feb 8, 2017 at 3:10

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