Poker is a card game played by two or more players. It originated in the sixteenth century as a bluffing game. It evolved into a game of chance in which each player bets according to his or her hand strength and the probability of making a winning hand. The game of poker as we know it today includes betting rounds and a showdown.
A standard poker hand consists of two cards of the same rank and three unrelated side cards. It may be broken down into one of four categories, with the highest hand winning the pot. Ties are broken by the kicker, a special card that is used to break ties between identical hands.
In each betting interval (round) a player puts chips into the pot by calling, raising, or dropping. A player that raises puts in the same amount of chips as his or her opponent; a player who calls puts in additional chips to stay in the hand. If a player does not call, he drops and forfeits his or her chips that are in the pot.
The first player to act places his or her bet in the first betting round. Then each player in turn has the option to match or raise that bet. If a player does not raise, he or she must check. If a player raises, other players may call that amount by putting in the same number of chips into the pot as the original raiser.