Blackjack, also known as Twenty-one or Vingt-et-un (French : "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 French decks of 52 cards.
The player is dealt an initial two card hand with the option of drawing cards to bring the total value to 21 or less without exceeding it, so that the dealer will lose by having a lesser hand than the player or by exceeding 21. Many rule variations of blackjack exist. Since the 1960s, blackjack has been a high profile target of advantage players, particularly card counters, who track the profile of cards yet to be dealt, and adapt their wager and playing strategy accordingly.