Blackjack Cheating

Marking cards while you play is another popular method. "The Daub" technique is done by clandestinely applying a substance that leaves an almost invisible smudge on the card. High value cards like tens are usually the targets. (One scam involved the use of a special paint that was only visible to specially made contact lenses.) The "hold out" method requires the palming of a card and substituting a better one. This is usually done when there is big money bet on the hand. One of the risks to these methods is when the deck is changed since the pit boss always scrutinizes the decks after they are taken out of play.

Other methods entail playing two hands and switching cards from one hand to the other, counterfeiting cards and/or casino chips, and adding chips after a winning hand. Some dealers may be careless when looking at their hole card for a BlackJack. A person behind the dealer on the other side of the pit may be able to discern the card. The value is then signalled to a player at the table. Wireless signalling devices have been used for various purposes but some casinos have new electronic detection systems that monitor certain frequencies for activity.