Poker is a card game played between two or more players and involving betting. Its variants are played in homes, clubs, and casinos, and it is popular among the public in the United States, where it has become a cultural phenomenon with an enormous amount of media coverage and a lexicon of associated terms. It is also widely regarded as the national card game of the United States, and its play and jargon permeate American culture.
While the outcome of any particular hand largely involves chance, long-run expectations are determined by player actions chosen on the basis of probability, psychology, and game theory. In addition, bluffing is a significant element of the game.
Players begin by placing a minimum bet of one low-denomination chip into the pot for every turn of play. Each player may then increase the size of his or her bet in increments determined by the game rules. When all players have placed chips into the pot, the cards are revealed and the best poker hand wins the pot.
Unlike most card games, poker has no fixed number of hands that must be made to win a game; any pair or higher-ranked combination of pairs wins. The highest pair beats any straight and the highest three-of-a-kind beats any full house. Ties are broken by the highest unmatched pair (four of a kind) or secondary pairs (threes of a kind and a pair).
Professional poker players use various strategies to gain information about opponents, such as studying tells. Tells are unconscious physical cues, such as a change in posture or facial expression, that reveal information about the player’s hand. In online poker, where in-person knowledge of opponent behavior is difficult to acquire, experts use software to build behavioral dossiers and even to buy records of other players’ “hand histories.”