What "perpetual check" means in chess

A perpetual check is a situation where one player can give repeated checks to their opponent's king, without being able to deliver a checkmate or make any progress towards winning the game.

A perpetual check can occur in various ways, but one common scenario is when a player has a more mobile and active position, and is able to continually harass the opponent's king with checks, forcing them to constantly move their king and repeat the same position.

Perpetual check can be a useful tactic for a player who is behind in material or has a worse position, as it allows them to salvage a draw from a potentially losing position. On the other hand, if a player is ahead in material and has good winning chances, allowing a perpetual check can be a serious mistake, as it may lead to a drawn game instead of a win.