Hole carding

In card games, hole carding is the obtaining of knowledge of cards that are supposed to be hidden from view. The term is usually applied to blackjack but can apply to other games with hidden hole cards, like three card poker and Caribbean stud poker. So long as it does not involve the use of a device like a mirror, actions like touching the dealer's cards, or having another person read and signal the hole card, in most jurisdictions hole carding is a legal form of advantage gambling. In some games, like stud poker, casinos normally have rules against rubbernecking or having a confederate stand behind an opponent to signal hole cards.

Blackjack players must usually make playing decisions based on only seeing one of the dealer's cards (the upcard). But if the dealer's hole card is spotted, a player who plays correctly has a theoretical advantage of up to 13% instead of the normal player disadvantage of around 0.5%. A hole-card player will often choose not to make certain plays, such as hitting (or surrendering) a hard 19 against a dealer 20, so as not to reveal that he can see the dealer's hole card.

This technique is not applicable in most games outside of the United States where the second dealer card is normally not dealt until all players have played.