 There are various types of information players can possess or lack about a game. First and foremost, players can be uncertain about the types of opponents they face: their preferences, their reasoning about the game and how they expect the game to unfold. Second, agents’ uncertainty can extend to the game itself. Players, of course’ won’t know their opponents choices in a simultaneous move game. Besides, agents might also have limited information about past moves and events. Such uncertainty can arise from the game structure eschewing certain observations, but also from failing to record past information properly. In yet more extreme cases, agents might even be unsure about the moves available to their opponents.