In chess, check is a situation in which a player’s king is directly attacked by one or more of the opponent’s pieces. When a player gives check, the opponent must immediately deal with the threat — no other move is permitted.
There are exactly three ways to escape check: move the king to a square that is not under attack, interpose a piece between the king and the attacking piece (only possible against a long-range attacker such as a rook, bishop, or queen), or capture the piece delivering the check. If none of these three options is available, the king is in checkmate and the game is over.
In practice, giving check is not always the right decision. Before doing so, ask yourself whether the check genuinely improves your position or creates a concrete threat. A poorly timed check can force your opponent’s king to a better square or allow them to capture your attacking piece with gain. Reserve checks for situations where they fit into a clear and purposeful plan.