Blackjack is a banking card game in which each player competes against the dealer, not the other players. The aim is to finish with a total closer to 21 than the dealer’s, without going over. It descends from the older game Twenty-One and is related to Vingt-et-Un and Pontoon.
Card values are fixed: two to ten count at face value, jacks, queens and kings count as ten, and an ace counts as one or eleven, whichever helps the hand. An ace and a ten-value card as the first two cards make a natural, or blackjack. On each turn a player can hit, stand, double down, split a pair or, where allowed, surrender.
Casinos deal from one to eight decks, and rules vary between variants such as European Blackjack, American Blackjack, Blackjack Switch and Spanish 21. Small rule changes, such as whether the dealer hits soft 17, move the house edge, so operators should publish each table’s rules.