Rook endgames are a crucial phase in chess where players must utilize their rook effectively to secure a win or draw. Key techniques include the principle of opposition, where the player with the king in front can control the game, and the importance of activating the rook to cut off the opponent's king from key squares. Another vital technique is the concept of creating passed pawns. By advancing pawns without opposition, players can distract the opponent's rook and king, allowing for potential promotion. Mastering these techniques can significantly improve a player's endgame strategy and overall performance.