Poker is a card game that involves betting against other players. It can also involve bluffing, which is an important part of the strategy. Players compete to have the highest poker hand, which consists of five cards of matching rank. The highest poker hand wins the pot. There are several variants of the game, which differ in the number and arrangement of the cards, the suits, and the rank of the ace (which can be high or low).

Poker has numerous strategies, including bluffing, by which a player can misinform his opponent about the strength of his hand. Some bluffs are obvious, while others may be more subtle, such as placing small bets to maintain the pot size or threatening to raise it. A good poker player will understand their own emotional state as well as that of their opponents and will adapt their strategy accordingly.

The game is popular with professionals, as well as amateurs who play for fun or for a living. Many professional players have a deep understanding of mathematical game theory, and use that knowledge to gain an edge over their opponents. This understanding has resulted in a flurry of software tools called solvers that can mathematically analyze an entire hand of poker and predict its chances of winning.

Poker has a long history and has evolved into many different styles and game variations. The earliest poker games were based on a variety of earlier vying games, such as Belle, Flux and Trente-un (French, 17th – 18th centuries), Post and Pairs (English and American, 18th century – present), Brelan (French, 17th – 19th centuries) and Bouillotte (French, late 18th – early 19th century). Other early games were based on dice, such as the game of shinty, which may have influenced poker.