Poker is a card game of chance, but also involves skill. While the outcome of any particular hand significantly involves chance, a skillful player will maximize long-run expectations by taking actions chosen on the basis of probability theory, psychology, and game theory.

During each betting interval, or round, a player must either call the amount bet by the player to his or her left, or raise it. A player who raises must put into the pot at least as many chips as the preceding player was required to call. Alternatively, a player may “drop” (fold), leaving no chips in the pot, and forfeiting their chance to win that round.

While most games of poker award the pot to the highest-ranked hand, there are a number of variations that divide the pot between the lowest and highest hands. These games are sometimes called high-low split or stud poker.

The rules of the game of poker vary from one place to another, but there are a few standard rules that apply to all variations. These include:

Every poker player has tells – unconscious habits that reveal information about their hand. These can be as simple as a change in posture or as complex as body language. Some tells are so subtle that the players themselves don’t even notice them. Other tells are more obvious and can be read by other players. Some of these are called physical tells and include eye contact, facial expressions, body language, and gestures.