Poker is a card game in which players place bets (representing money) into the center pot. The highest hand wins the pot. Players may also bluff, betting that they have a superior hand when in reality they do not, hoping to win by convincing other players to call their bets. In the long run, successful poker players make decisions on a combination of factors that include probability, psychology and game theory.

In most games, the first player to act must pay an ante (amount varies by game). The dealer then shuffles the cards and deals them one at a time starting with the player to his or her right. The players then have the option to call, raise or fold. If they choose to call, they must place enough chips in the pot that they are at least equal to the amount placed in the pot by the player to their left.

A standard poker deck contains 52 cards. Each card has a rank (aces, kings, queens and jacks) and a suit, though some poker variants will use wild cards instead of the suits. A hand is ranked according to its mathematical frequency, with higher hands beating lower ones. Ties are broken by the highest unmatched card or, in a full house, the highest pair. For example, a royal flush beats any four of a kind or straight. Players can also form a high-low hand by holding any two of the same card.