What are weak squares in chess; how can they help to mate another player? I read this concept in a book but I didn't understand much about the concept. Can anybody explain this concept with an example?
This is a very common example.

[FEN "6k1/5p1p/5BpQ/8/8/8/8/6K1 w - - 0 1"]


Do you see the weak dark squares around the king? Checkmate is possible because those squares are weak and can't be defended.