Poker is a card game of skill and chance, played by two or more players. The game is a social activity in which participants make bets based on the strength of their hands, and attempt to win the pot by winning all or most of the remaining chips in a showdown. It is one of the few games where the result depends on both luck and player skill. It is also a psychological game, as players can strategically misinform other players by bluffing with a strong hand or betting large amounts when they have a weak one.
Unlike other card games like chess, where the information is completely known to all players, poker hands mimic real life in that resources are committed before all of the facts are in, and no player can ever have total command over the information until the end of the hand. Consequently, poker offers many mechanisms for players to misinform each other about the strength of their hand by raising and folding for various strategic reasons.
One of the key skills of a good poker player is to be able to read other players, and this includes learning about tells. These are not only physical tells like fiddling with their chips, but more subtle ways that a player might signal their hand strength, such as making an aggressive raise when they have a strong value hand and calling when they have a mediocre or drawing one.