Perpetual check is a chess tactic that involves repeatedly putting the opponent’s king in check, with the goal of forcing a draw by threefold repetition or the 50 move rule. This tactic is often used when one player has a material advantage but is unable to checkmate the opponent, or when the player has a lead in development but is unable to create a decisive advantage.
Perpetual check can be achieved by using a variety of pieces such as the queen, the rook, the knight, or the bishop. One of the most famous examples of Perpetual check is the “Perpetual check of Philidor’s position” which is a drawish endgame that can be achieved with the moves 1.e4 e5 2.Nf3 d6 3.d4 Nd7 4.Nc3 Ngf6 5.Bc4 Be7 6.0-0 0-0 7.Re1 c6 8.Bf4 and then repeating the moves.
Another famous example is the “Perpetual check of the Philidor’s Defense” which is a drawish endgame that can be achieved with the moves 1.e4 d6 2.d4 Nf6 3.Nc3 e5 4.Nf3 Nbd7 5.Bc4 Be7 6.0-0 0-0 7.Re1 c6 8.Bf4 and then repeating the moves.
To prevent Perpetual check, players should try to keep their king safe by castling early, they should also try to keep their pieces active, and try to create counterplay by attacking the opponent’s King. They should also try to keep their pieces coordinated and to have many defender pieces ready to respond to the opponent’s threats. They should also try to create a passed pawn, or create a decisive advantage, which can force the opponent to trade pieces and end the Perpetual check.