Blackjack, also known as 21, is a popular card game played in casinos around the world. The objective of the game is to have a hand value of 21 or as close to 21 as possible without going over.

The game is played with one or more decks of standard playing cards, and each card is assigned a point value. Cards 2 through 10 are worth their face value, face cards (jack, queen, king) are worth 10 points, and aces can be worth either 1 or 11 points, depending on which value would be more beneficial to the hand.

At the beginning of each round, players place their bets and are dealt two cards each. The dealer also receives two cards, one of which is face-up and the other is face-down. Players can then choose to “hit” (receive additional cards) in an attempt to improve their hand or “stand” (keep their current hand).

The goal is to have a hand value closer to 21 than the dealer’s hand without going over. If a player’s hand exceeds 21, they “bust” and lose their bet. If the player’s hand value is lower than the dealer’s, they lose their bet. If the player’s hand value is higher than the dealer’s and does not exceed 21, they win and are paid out 1:1 on their bet.

There are also several additional options available to players, including splitting pairs (turning two cards of the same rank into separate hands), doubling down (doubling the initial bet and receiving only one additional card), and taking insurance (betting on the dealer having a natural blackjack).

Blackjack is a game of strategy as well as luck, and there are various strategies and betting systems that can be used to increase the chances of winning. However, it is important to note that the house always has a mathematical advantage in the game, and there is no guaranteed way to win.