Blackjack, also known as twenty-one, is the most widely played casino banking game in the world. Blackjack is a comparing card game between a player and dealer and played with one or more decks of 52 cards.
The player or players are dealt an initial two card hand and add the total of their cards. Face cards (Kings, Queens, and Jacks) are counted as ten points. The player and dealer can count their own Ace as 1-point or 11 points. All other cards are counted as the numeric value shown on the card. After receiving their initial two cards, players have the option of getting a "hit" (taking additional cards) to bring their total value of cards to 21 points, or as close as possible without exceeding 21 (called "busting"). If a player holds an ace valued as 11, the hand is called "soft", meaning that the player cannot go bust by taking an additional card; otherwise, the hand is "hard".
The dealer has to take hits until his cards total 17 or more points. (In some casinos, the dealer also hits on a "soft" 17, e.g. initial ace and six.) Players who do not bust and have a total higher than the dealer, win. The dealer will lose if he or she busts, or has a lesser hand than the player who has not busted. If the player and dealer have the same point total, this is called a "push" and the player typically doesn't win or lose money on that hand.
Many rule variations of blackjack exist. Since the 1960's, blackjack has been a high profile target of advantage players, particularly card counters, who track the profile of cards that have been dealt and adapt their wager and playing strategies accordingly.
Other casino games inspired by blackjack include Spanish 21 and pontoon. The recreational British card game of black jack is a shedding-type game and unrelated to the subject of this article.