Bluffing is a tactic where a person deceives their opponents on purpose in order to gain an advantage. A game can be designed in order to allow for bluffing to emerge.
As a design pattern bluffing requires that the players be able to conceal information from their co-players. Complex behaviours and strategies can emerge through bluffing.
Of course, a second premise for bluffing is a game of competition.
Bluffing is a case of the information awareness pattern. The difference is that in the general case control of information depends on the system or on the game. In the bluffing pattern, control of the relevant information is at the hands of the player who bluffs.
A failed bluff can have implications in terms of penalty or score.
The game play of the location-based mobile game Invisible city: Rebels vs. spies is designed around the bluff pattern.