Poker is a card game that can be played by two or more people. The game is based on probability and the expectation of other players’ behavior. The best poker players use their knowledge of probabilities to make decisions about whether to call, raise, or fold. They also consider their opponents’ “tells,” or unconscious habits that reveal information about their hands. These tells can be as subtle as a change in posture or gesture.

The game starts with a round of betting after each player receives their hole cards. This round is initiated by mandatory bets called blinds that are placed into the pot by the players to the left of the dealer. These bets are not optional, so they create an incentive for players to play.

After the initial betting rounds, the flop, turn and river are dealt. Each of these cards can change the value of a hand. For example, a pair can become three of a kind or a flush can become straight. The higher the hand is, the more money it will be worth.

The flop, turn and river are a key part of the game because they can change the probability of winning a hand. For example, if you have two hearts and the flop is all diamonds, then it is unlikely that you will win. This is because the odds of hitting your three required cards on the flop, turn and river are much lower than if you had just one heart.