Underpromotion Tactic Puzzle (Rated 857): Promote — Back Rank Mate

This chess endgame shows how a passed pawn can decide the game by promoting with tempo. When a pawn reaches the last rank, the new piece can create immediate tactical threats, including checkmate, before the opponent can coordinate a defense. In this position, the advanced pawn race is not just about material; it is about forcing a direct finish. Recognizing when promotion also delivers mate is a key practical skill in classical chess.