A few ways to implement secret positioning or secret movement:
http://boardgames.stackexchange.com/questions/7492/how-can-you-have-secret-units-on-the-board
Tips & Resources for Board Game Designers
A few ways to implement secret positioning or secret movement:
http://boardgames.stackexchange.com/questions/7492/how-can-you-have-secret-units-on-the-board