The answer is for black to play R-e1 check. White is forced to play K-g2. Black then plays N-e3 check. If white moves the king, then black plays N-f5 which attacks the white queen and prevents the mate. If white plays pxe3 instead, black follows with Q-c2 check and then there is an easy series of checks that depending on play, either win the f6 pawn, the white queen or the game.
I hope you found the answer. Look for another of these challenging chess puzzles in my next post! If you would like to begin having these puzzles sent to you, just add your email address in the “Subscription Options” box and click “Subscribe.”