Black has to play g6, otherwise it's mate on g7.
Enjoy your free rook.

Remember this position, opposing your queen with the opponent’s king can be really useful. The pawn can’t take back the bishop, and has to protect the mate threat, revealing the rook.



Now let's go back to ITH for the last part : Relative Piece Value.
http://www.itstoohard.com/puzzle/Qz69Ofgj