Perfect information refers to the situation in which an agent has all the relevant information with which to make a decision. It has implications for several fields. In game theory, perfect information describes the situation when a player has available the same information to determine all of the possible games as would be available at the end of the game. In game theory, a game is described as a game of perfect information if perfect information is available for all moves. Chess is an example of a game with perfect information as each player can see all of the pieces on the board at all times. Other examples of perfect games include tic tac toe, irensei, and go. Games with perfect information represent a small subset of games. Card games where each player's cards are hidden from other players are examples of games of imperfect information.