How to Cheat at Poker Using Marked Cards

Apart from card mechanics and collusion, there is another way of cheating at poker: using marked cards. Marked cards cheating does not require any sleight of hand and can be performed by one single person. Marked cards cheating is applicable to home games where the deck is shuffled, but not replaced, and is especially effective if the cheat can replace the entire deck with one he has marked before. The hard way to do it is switching the deck during shuffling. The easy way is involving the host of the game in cheating.

Methods:

• Cards are commonly marked by one point placed at a certain position of an invisible circle at the back side of the card. These marks are read as a clock-face: a point at 1'o clock means a 2, a point at 2'o clock means a 3 and so on until a point at 12'o clock, which means a King. A card without a mark is an Ace.
• If the cheat can prepare a deck of marked cards before the game starts, he can do it in several manners: he can scratch the points, he can cover the location of the point with a small object and than shade the card backs at the sun or use paint or varnish. The cheat will try to make the marks as invisible as possible, but if another person at the table knows to read marked cards, the cheating can be discovered.
• Advanced cheats make marks with invisible varnish, which can only be seen through special glasses or contact lenses the cheat wears during the game. Wearing sun glasses is common in poker, and you certainly can not say anything to a person that wears optical glasses. However, if a player with glasses is suspected of cheating, he may be asked to take the glasses off. The situation with contact lenses is worse. Normally, you can not even tell if a person wears contact lenses. However, it is said that a person who wears special contact lenses to read invisible marks can be recognized by red glow around the pupil visible under a certain angle.
• Actually, playing with a pre-arranged deck of marked cards often is not the case. Cheats can mark the cards during the game. This is done by creasing the angles of the card or by pressing the back of the card with a nail. To prevent this kind of cheating you can demand to replace the deck each time you have reasons to believe that the cards were marked.