A game of strategy where players try to finish their hand with a total higher than the dealer’s without going over 21. It is played by two or more people using one to eight 52-card decks. Number cards (2-10) have their face value, the Ace can be treated as either 1 or 11, and the jack, queen, and king are each valued at 10. The rules are regulated by gaming commissions, but casinos may allow rule variations. The player’s goal is to beat the dealer’s hand without going over 21, and a blackjack pays 2-1.

The game of blackjack has long been the card game of intellectuals and those who like a chance of beating the house. In 1956 a group of U.S. Army mathematicians—known as the Baldwin group—published an article in the Journal of the American Statistical Association that described for the first time a mathematically correct set of rules for the game, known as basic strategy. These rules dictate which action a player should take in any given situation.

In a traditional blackjack game, each player is dealt two cards face down and the dealer receives one card face up from a shoe (a boxlike device that houses the cards). If the dealer has an ace, it must be hit until they have a total of 16 or higher; otherwise, they must stand. If the player has a hand totaling 21 or closer than the dealer, they win; if the player and dealer have the same total, it is a push and the player gets their original bet back.

A player’s skill in blackjack is largely determined by their understanding of the rules, and their ability to use those rules to make the best decisions in every situation. Novices lack this understanding, and often make poor choices that result in losses. In contrast, expert players understand the game inside and out because they have spent many hours studying it.

The biggest mistake novices make is playing too conservatively, especially when their hands are strong. They will often stand when they should hit, and they will fail to double down and split pairs as frequently as they should. This allows the house to take advantage of their misguided caution.

Experts, on the other hand, will exploit every opportunity to maximize their wins. They will play more often when the odds favor doing so, and they will split and double down more than novices do, allowing them to reap larger rewards. These big wins will not always be in the form of a blackjack, but they will be there more often than the small rewards that novices receive for their conservative play. It is this difference in understanding that separates the high achievers from the losers in blackjack. The house edge in blackjack is lower than that of most other casino games, but the gap will widen if a player deviates from basic strategy. For this reason, it is important to know the basic rules of blackjack before you sit down at a table.