the White Queen will also control f8. So the Black King moving to f8 would be against the rules of chess. 1.Qh8 is Checkmate! If it’s Black turn to play in the Diagram position, he can deliver 1 ...

White (to move) has three queens against a lone black king, and it’s checkmate in seven moves, but there’s a catch. The queen trio are only allowed to move on the extreme left-hand file from ...