1. threatened squares: Displays the status of each piece on the board. A red square means that the piece is under attack and not sufficiently defended, or that it is being attacked by a piece of lesser value. This is usually a pretty serious danger signal and means you must take active measures to avoid losing a piece. Yellow means that the piece is under attack, but it is just sufficiently defended. You must be careful about removing any defending piece. Green means the piece has enemy contact but is well defended. Usually it is okay to remove a defending piece.
Excellent APP !! Easy to install and works without flaw; Chess Engines and the GUI Chess for All work fantastic on Android phones and take seconds to install. These are great tools for analyzing chess games.
Best in play store Very intelligent
Very best !!!
Sandeep chess man
Added: request permission for EXTERNAL-STORAGE.