A game in which players place chips into a pot based on decisions made on the basis of probability, psychology and game theory. The game has a wide range of variants and was well established by the nineteenth century. It is an international card game that has many variations, including the well-known Texas hold’em. It has a reputation for being a game of chance, but in fact much of the long-run behavior of players depends on their choices, influenced by probability and psychology, rather than on luck.

There are several forms of poker, but in most games one player has the “dealer” position (marked by a dealer chip in the photo) and acts last at each betting phase. All players start with two cards, and aim to make a five-card hand using these plus the five community cards that are dealt. The winner of each hand wins the pot, which consists of all the bets placed during that deal.

If a player doesn’t like his or her two cards, they can discard them and draw new ones from an undealt portion of the pack. This may help to improve a weak hand, or provide opportunities to bluff.

A player may also choose to call a raise (called a bet) with the amount he has staked, but only if he can match the size of the last raiser’s. If he cannot do so, he must fold his hand and drop out of the competition.