Poker is a card game where players try to make the best possible hand. It is one of the oldest games, and has been popular in many countries for centuries.

The game begins with a dealer, who deals cards to the players, one at a time. Depending on the type of poker being played, the cards are dealt face up or face down.

Each player in turn has the option to fold, call, or raise. The small blind is the first to act; if no one raises, the big blind is next in line to act.

Once all players have made their initial bet, the dealer reveals one card from the deck, which is called the flop. The small blind is then the first to act in this and every succeeding round of betting, by folding, calling, or raising.

In some versions of poker, the dealer can also change the number of cards in the pot during the course of a hand. This is often done to keep the game fair and to encourage a player to call or raise.

In poker, a hand is ranked by its odds (probability). The highest possible hand is a royal flush, which contains 10 cards of the same suit, one kind (all clubs, diamonds, hearts or spades). Straights consist of 5 consecutive cards of the same suit; a full house includes three of a kind and two pair; and a flush is any five cards of the same suit.