Lack of informational asymmetry:

There  are games  in which  there  is lack of informational asymmetry, that is, some players know some information, which the others do not know. Then the players attempt  to infer,  conceal, or sometimes convey this information. Information becomes an important part  of the game  and  the strategies. The general principle is that a player releases information selectively. Players want 

to  reveal good  information (that kind that will draw responses from the other players that work  in her favour) and conceal the  bad (the kind  that may work to someone's bad). But in a strategic game, opponents are rational players and know  that their opponents are also  rational. Therefore, they are not going to believe the unsupported declarations about their opponent's progress or capabilities. They can be convinced only by actions that are credible proof. Such  actions on  the  part  of the more informed player  are  called  signals and the strategies that use them are called signaling.  

Conversely, less informed  players  can  create  some  situations  in  which the more  informed players have to take some action that will  credibly reveal her information; such strategies are called screening and  the methods they  use  is called screening devices.