Poker strategy is a complex subject. This article only attempts to introduce basic strategy concepts.

The fundamental theorem of poker

main: Morton's theorem The fundamental theorem of poker, introduced by David Sklansky, states that every time you play your hand the way you would if you could see your opponent's cards, you gain and every time your opponent plays his cards differently from the way he would play them if he could see your cards, you gain. This theorem is the foundation for many poker strategy topics. For example, bluffing and slow-playing (explained below) are examples of using deception to induce your opponents to play differently than they would if they could see your cards. There are some exceptions to the fundamental theorem in certain multi-way pot situations, as described in Morton's theorem.

Pot odds, implied odds and poker probabilities

main: poker probability The relationship between pot odds and odds of winning is one of the most important concepts in poker strategy. Pot odds are the ratio of the size of the pot to the size of the bet required to stay in the pot. For example, if a player must call $10 for a chance to win a $40 pot (not including his $10 call), his pot odds are 4-to-1. To have a positive expectation, a player's odds of winning must be better than his pot odds. If the player's odds of winning are also 4-to-1 (20% chance of winning), and if he plays the pot five times, his expected return is to break even (losing four times and winning once).

Implied odds is a more complicated concept, though related to pot odds. The implied odds on a hand are based not on the money currently in the pot, but on the expected size of the pot at the end of the hand. When facing an even money situation (like described in the previous paragraph) and holding a strong drawing hand (say a four-flush) a skilled player will consider calling a bet or even opening based on their implied odds. This is particularly true in multi-way pots, where it is likely that one or more opponents will call all the way to showdown.

Deception

main: Slow play (poker) By employing deception, a poker player hopes to induce his opponent(s) to act differently than they would if they could see his cards. Bluffing is a form of deception to induce opponents to fold superior hands. If opponents observe that a player never bluffs, they won't call his bets unless they have very good hands. Slow-playing is deceptive play in poker that is roughly the opposite of bluffing: betting weakly with a strong holding rather than betting strongly with a weak one. If opponents observe that a player never slow plays, they can pounce at any sign of weakness.

Position

main: Position (poker) Position refers to the order in which players are seated around the table and the strategic consequences of this. Generally, players in earlier position (who have to act first) need stronger hands to bet or raise than players in later position. For example, if there are five opponents yet to act behind a player, there is a greater chance one of the opponents will have a better hand than if there were only one opponent yet to act. Being in late position is an advantage because a player gets to see how his opponents in earlier position act (which provides the player more information about their hands than they have about his). Position is one of the most vital elements to understand in order to be a long-term winning player. As a player's position improves, so too does the range of cards with which he can profitably enter a hand. Conversely this commonly held knowledge can be used to an intelligent poker player's advantage. If playing against observant opponents in tournament style play (when the amount of chips one has is finite, which is to say there are no 'rebuys') then a raise with any two cards can 'steal the blinds,' if executed against passive players at the right time.