A game of chance, poker is played by two or more players on a table. Each player has two cards that form their individual hand and then five community cards that are revealed later on in the game. Bets are made and players can call, raise or fold their hands depending on the strength of their hand and the betting patterns of other opponents.

The rules of poker vary widely, but most games include forced bets (ante and blind) that are placed into a central pot before players receive their cards. The game also usually involves betting rounds that are triggered by the appearance of certain cards, called the flop, turn and river, respectively. Players can bluff in these rounds, trying to deceive opponents into believing their hand is strong when it actually is weak, or to prevent others from raising their bets too high.

During the final betting phase, players reveal their hands and the person with the highest ranking hand wins the pot. Ties can occur if two players have identical hands (e.g., a pair of fives). In such cases, the higher kicker rank breaks the tie.

Online poker eliminates the ability to read in-person cues that might give away a bluff, but expert players compensate for this loss by building behavioral dossiers on their opponents and even buying records of other players’ “hand histories.” This information is used to exploit opponents while protecting oneself from them. The game offers many mechanisms by which players strategically misinform each other, and mathematical game theory pioneers John von Neumann and Oskar Morgenstern analyzed poker as a key example in their 1944 book Theory of Games and Economic Behavior.