lyonbeast vs Kirill_Klukin

White played 119.Kf7, moving the king from g6 to f7. The move abandons the defensive shield that the king provided to the rook on a6 and the bishop on d7. By stepping onto f7 the king walks into the line of the black rook on e5, which can now give an immediate check on f5. The position already shows that White's rook on a6 and bishop on d7 are undefended, while Black's rook on e5 is also undefended. By playing Kf7 White allows Black to activate the rook with a forcing check, losing material or allowing a perpetual attack.

The engine’s recommendation 119.Re6 keeps the rook active and attacks the undefended black rook on e5. After 119.Re6, Black’s best reply is 119...Rxe6+ which trades a rook for a rook but removes the dangerous rook from the e‑file and leaves White with a bishop versus a bishop and a pawn, preserving the material balance. In contrast, 119.Kf7 lets Black play 119...Rf5+! winning the rook on a6 or forcing the white king into a vulnerable position. The engine move neutralises the immediate rook threat and trades on equal terms, whereas the king move creates a tactical liability.

Never expose your king to opponent's rook lines in the endgame: When the opponent’s rook can give a check from a nearby file, keep the king shielded and look for active piece moves that neutralise the threat. In this position the correct move was the rook infiltration Re6, not a king step that walks into a rook check.