Poker is a card game of skill that involves betting between two or more players. It is believed to be an ancestor of blackjack and rummy. The game is played around the world and has many variants.

The goal is to win the pot by forming a high-ranking hand consisting of five cards. The value of a hand is in inverse proportion to its mathematical frequency, so that more unusual combinations are more valuable. The game also allows players to bluff by betting that they have a strong hand when they do not, causing other players to call (match) the bet or concede the hand.

In most games a player puts the amount of chips they wish to bet into the pot during their turn, and any other players who are still in the hand must either call this bet with their own stake or raise it. Players can only make one raise in a single betting round, but may raise again later in the same betting round. If a player cannot match a raised bet with their remaining stake, they must fold their hand.

Reading tells is an important part of the game; some classic tells include a drooping eyelid, nostril flaring, a flushed face, eyes watering, an increasing pulse seen in the neck or temple, and a hand over the mouth to conceal a smile. Players may carry extra chips in their pockets to allow them to top up without interrupting the flow of play or inconveniencing the dealer.