Poker is a card game in which players place bets, called “calls,” into a pot and win the hand by demonstrating that they have the best cards. It is a game of chance, but in many variations the game also involves bluffing. A player’s decisions are based on the combination of probability, psychology, and game theory.

The object of the game is to make bets that maximize the long-term expected value. These bets are made in response to the actions of other players, and may include raising and folding. Some bets are forced, but most are voluntarily placed into the pot by players who believe that their action has positive expected value.

It is important to remember that even a bad poker hand can still win the pot. The key is to be careful not to overplay weak hands. For example, pocket kings can be destroyed by an ace on the flop. Similarly, a good flop can ruin a strong pre-flop holding if there are too many flush or straight cards in the board.

It is also important to understand how stack depth affects strategy. In tournaments, especially short-handed ones, it is necessary to be able to read the other players and understand their logic. This isn’t always possible with subtle physical tells, but understanding their betting patterns can help you determine the strength of their hands and avoid calling bets that aren’t profitable. It is also important to pay attention to stack depth at the bubble of a tournament, since this is where players tend to play their strongest hands.