Poker is a card game that involves betting by players around the table in the form of chips. The objective is to win the pot, which is the total of all bets made in a deal. Players make bets voluntarily on the basis of expected value, psychological factors, and bluffing. In this way, while the outcome of any particular hand significantly involves chance, the long-run expectations of poker players are determined by their actions chosen on the basis of probability, psychology, and game theory.

Poker has a wide variety of variants, differing in betting types (limit versus no-limit), formats, events (cash games versus tournaments), and stakes. Despite these differences, it is possible to generalize about the strategy of the game. In 1944, mathematician John von Neumann and economist Oskar Morgenstern published a foundational book on mathematical game theory in which they used poker as an example.

The most important aspect of poker is understanding how to weight your chances to maximise profit. Annie writes that it’s easy to fall into the trap of what poker players call resulting, which is starting at an outcome and working backwards to either validate or lambast the decision-makers. Instead, she advises, you should always be willing to admit if your decision wasn’t the best but still weigh your options to ensure you maximise profit.

This is particularly true when it comes to assessing the state of the board after the flop, turn, or river. It is common for a player who initially had the best statistical hand to lose to an opponent on one of these subsequent rounds.