4.6. Information¶

How much of the game state is visible to each player? Changing the amount of information available to players has a drastic effect on the game, even if all other formal elements are the same. Some examples of information structures in games:

• Perfect Information Some games offer total information, where all players see the complete game state at all times. Chess and Go are classic board game examples.

• Imperfect Information In this style of game some information is hidden from some of the players. Think of Hearthstone where you only know what cards your opponent has played, not what is currently in their hand or yet to be drawn from their deck.

  Variations on imperfect information:

  • One player can have their own privileged information, while other players do not. This is common in one-against-many player structures, like Scotland Yard.
  • The game itself can contain information that is hidden from all players. Games like Clue and Sleuth actually have the victory condition that a player discover this hidden information.
  • These can be combined. Many “real-time strategy” computer games use what is called “fog of war” where certain sections of the map are concealed to any player that does not have a unit in sight range. Some information is therefore hidden from all players. Beyond that, players cannot see each other’s screens, so each player is unaware of what information is and isn’t available to their opponents.