Poker is a card game that can be played by two or more players. It can be played with different rules and variations, but the basic game is always the same: the players make forced bets before the cards are dealt, and then after each betting interval, or “round,” the players show their hands, and the player with the best hand wins. There may be several rounds of betting, and at some point the cards are gathered into the center of the table, known as the pot. In some cases, a player may choose to forfeit his or her cards and place all of his or her chips into the pot, which is called going all-in.

To play poker, a deck of 52 cards is used. Each player must make a bet before the cards are dealt, which is usually the amount of the blind bet plus an ante. Each player then receives five cards, and after the final round of betting, shows them. The winner is the player with the highest hand, which must consist of at least three cards and cannot be made up of straights or flushes, but can contain four of a kind or three of a kind.

The rules of poker are based on probability theory, but the skill of the player also plays a role. A good poker player understands how many cards are left in the deck, what the odds are of getting a particular card, and what cards other players are holding. A player can use this information to calculate the probability of a particular type of hand, such as a flush, a straight, or a pair.

A poker game can be played with or without money, but it is almost always played with poker chips. Each chip has a specific value; for example, one white chip is worth the minimum ante or bet, while a blue chip is worth five whites. The game is often agreed upon ahead of time that any winnings will be split evenly between the players, and there are also rules about how to determine who won if the outcome of the game is unclear.

The history of poker stretches back to ancient times, and it has evolved over the centuries. There are many different games, and a number of variants on the game have been developed, some of which are more closely related to the modern game of poker than others. Early vying games with three cards include Belle (French, 17th – 18th centuries), Flux and Trente-un (French, 17th century), Post and Pair (English and American, 16th – 19th centuries), Brelan (French, late 18th century) and Bouillotte (French, 18th century). There are also a variety of four-card games, but most of them have little relevance to poker.