Poker is a card game in which players place bets based on probability and psychology. The outcome of a hand is determined by chance, but long-run expectations are decided upon by actions taken on the basis of probability theory, game theory, and psychology. The game is played with chips (representing money) in betting intervals, which are called rounds. After a round has been completed, the cards are revealed and the winning player takes the pot. During the course of a hand, each player has to make resource commitments before all of the information is available; this reflects real life where resources must be committed before the full picture can be seen.
A poker hand consists of five cards. Each card has a value in inverse proportion to its mathematical frequency; thus, the more unusual the combination of cards, the higher the hand rank. The game may also involve bluffing; a player may bet that they have a superior hand when they do not, hoping to fool other players into calling their bet.
Poker is a popular recreational game, and in many places is legal to play with a minimal amount of money. However, the game has a reputation as a gambling activity and some jurisdictions have banned it. Poker has also been the subject of debate over whether it involves substantial skill or is purely luck. The emergence of online poker has increased the interest in the game in recent years, and there are now several professional tournaments with large prize pools.