Card marking is a common method of cheating in poker. It involves making subtle marks on the cards that can only be seen by the marker or conspirator, and it allows them to determine a card’s value without having to flip it over. It is a common form of cheating in both home games and in casinos.
How to spot marked cards
One way that players can mark their cards is by rubbing them with something that will leave a trace on the back of the card. This can include anything from scratching with a fingernail to leaving a crease on the card. Other ways to mark cards are more sophisticated, such as using invisible ink that can only be detected by certain devices or with a special light.
These techniques are difficult to do in front of other players, and they usually require a lot of practice. Moreover, they are time-consuming and are susceptible to human error. This is why most cheaters don’t use them in public games.
Another way to detect marked cards is by giving them the riffle test. This is a quick and easy way to see if the cards have been tampered with. However, this method is only effective if the dealer is not aware that there are marks on the cards. It is also possible to ask for a new deck of cards if you suspect that they are marked. But be careful when doing this, as it might tip off other players.