Poker is a card game with many variants that require skill and strategy to play well. Although there is some chance involved in any particular hand, the long-term expectations of players are determined by actions they choose on the basis of probability, psychology, and game theory. For example, players can bluff and raise bets even when they do not have a strong hand, in the hope that other players will call their bets out of fear that they have a stronger hand.
Each player is dealt five cards and places them in a betting pool, called the pot, along with any other cards they wish to add to their hands. The highest pair wins ties, except when the pair is equal (as in the case of a straight or a flush). If no one has any pair, then the highest unmatched card breaks ties.
The first player to act has the privilege or obligation of placing the first bet in each betting interval, depending on the rules of the poker variant being played. Each player in turn must place into the pot enough chips (representing money, for which poker is almost invariably played) to make his or her total contribution at least equal to that of the player before him.
After everyone has placed their bets, the remaining players participate in a showdown in which they reveal their cards and the player with the best hand wins. If no one has a winning hand, the remaining players may decide to continue playing by calling higher bets in order to entice others into adding more money to the pot.