In a game of complete information all players' are perfectly informed of all other players payoffs for all possible action profiles. Examples will be the Game of chicken, Prisoner's dilemma, chess,checkers etc. In all the above the players know about each others' utility function/payoffs. If instead a player is uncertain of the payoffs to other players the game is one of incomplete information. In an incomplete information setting players may not possess full information about their opponents. In particular players may possess private information that the others should take into account when forming expectations about how a player would behave. Examples would be situations such as buying auto insurance, playing blind poker etc.