Poker is a card game in which players bet on the strength of their hand of cards. The player with the highest ranked hand wins the pot, which consists of all bets placed during that round. The game can be played with a single or multiple decks of cards, and it can be played in cash games or tournaments.

Players place an initial amount into the betting pool before the cards are dealt, called forced bets (also known as ante or blind bets). Once the cards are dealt, the first of several betting streets begins. The players may continue to raise their bets, or fold, depending on the strength of their hands and the strength of their opponents’ hands.

A poker hand consists of five cards. The value of the hand is in inverse proportion to its mathematical frequency, with rarer combinations having higher values than more common ones. The highest hand is the royal flush, which consists of four aces, four kings, or any other combination of four of a kind.

Besides knowing the rules of poker, it is important to understand the psychology behind the game. This includes understanding how players think and act during the game, as well as reading their tells. A tell is a subconscious habit or movement of a player that gives away information about his or her hand. These tells can be as simple as a shift in body posture or as complex as an expression.