For the physical board game, how do you restrict the vision of PCs in situations such as fog?

For situations such as Obscureing Mist, darkness and other visual disabilities, how have you succeeded in the physical board game?

Success measurements:

  • Players can manipulate their character in a battle grid to explore the restricted viewing area
  • The DJ can interrupt players when their sensory information changes without significantly interrupting the game in each round.
    • Ideally, you should also avoid constantly moving them backwards.
  • Do you have any method to provide information to players about what their character perceives
    • Ideally, only the player who "should" have the exact knowledge would have it, and others only what they can convey

The good response (s) will follow the concept of Good subjective and cover key points:

  • What has been your experience using the system?
    • that is, comments from the players, how did you feel it worked
  • How could you restrict your view and also reveal information
    • Did you just tell the player? Did everyone know when Bob was next to the bad guy?

Related question to play online with the Roll20 virtual table: in Roll20, how do you restrict PCs? vision in situations like fog?