A deck is a set of 52 cards consisting of 4 suits with 13 cards in each suit and every card is unique in color and value. This implies that the probability of a card being the one that you want it to be is 1/52. Well, this is in an unforged and unbiased deck of cards. All the cards in the deck have exactly the same design on them. Thus a card can only be identified when the card is seen from the front. From the back because of the same design, no card can be identified and will always hold a 1/52 probability.
While this is true for all the unbiased decks, some decks have marked cards making them biased and unethical. Marked cards are the regular cards which have been altered so as to make them identifiable without looking at the front side of the card.
The cards could either carry a code that is mapped to the actual value of a card or the cards could be see through cards which have been made that way. Marked cards can be made by:
- Making alterations to the existing standard deck on spot so that the number on the card and the suit it belongs to can be identified. This is usually done to identify one or two cards.
- The whole deck can be marked and the cards can be printed in such a way that all the cards can be read from the reverse.
Marked cards are not used for fun, there are several reasons why a marked card is used.
It is not a coincidence that a person can read the cards from the rear view, it is a purposeful act. Cards might be played for fun, but are not marked for fun. The marked cards are usually used by a magician to trick the audience. The magician creates an illusion that he could read through cards but he is actually able to read the cards easily as they are marked. A set of marked cards can also be used in casino games or other competitive card games to get an undue advantage over other players.
Using marked cards is an offence:
These cards are used by the magician to may the audience believe in this magic skills and are used for the purpose of entertainment not really harming anyone. If you look at the other side, the marked cards can be used in poker or any other card game for cheating. In this case, the person using marked cards gets an undue advantage and assures winning. In this case, it is unfair on the other players and thus is an offence. The dealers involved in dealing marked cards or the players who use marked cards are believed to have committed a crime by cheating and are offenders.
Many casinos treat this as a severe offense and have strict policies to deal with such offenders. The repeat offenders are usually blacklisted and the ones involved in the scam of marking the cards are also prosecuted by the relevant court. Many casinos are strictly vigilant when it comes to accessing the decks used in dealing. There are certain software systems installed to ensure that the fraud deck of cards can be identified. Casinos also train their dealers to identify the scammed cards and to point of the marked cards.
Usage of marked cards is illegal in many countries and there are repercussions that the offenders have to face. The cases where the offender is found can be escalated to courts as a step next to blacklisting!