Poker is a card game in which individuals compete for an amount of money or chips contributed by the players themselves (the pot). The cards are dealt randomly, so players must make decisions based on the strength of their own hand and on their prediction of the chances that other players will call raises. The game can be played socially for pennies or matchsticks, or professionally for thousands of dollars.
The rules of poker vary between games, but all involve betting in rounds. Each player is dealt two cards, known as hole cards, face down, and five community cards are then revealed in stages – three cards on the flop, an additional card called “the turn,” and finally a final card called “the river” – allowing players to make combinations of their own two cards with the community cards to create a poker hand. Players may check, call, or raise during each betting interval.
A player is allowed to raise by no more than a set number of chips, which varies according to the game. This limit is generally higher at earlier betting intervals, and lower during later ones. It is possible to bet and raise without putting in any actual chips, although this is often considered poor form.
In most modern poker games, the best poker hands are ranked based on mathematics. The less likely a hand is to be dealt, the higher it ranks. However, in some games the rankings are based on the relative strength of the hands.