Fork Beginner Puzzle (Rated 978): Win a Rook Endgame Fork — Decisive Material Gain

This chess endgame shows how a single tactical idea can convert a seemingly balanced rook ending into a decisive material gain. The key motif is a fork created by a pawn advance that attacks multiple targets at once, forcing the king into a vulnerable square and opening a follow-up check. In classical chess, these positions often reward accurate calculation over general endgame principles, because one forcing sequence can decide the game immediately.