Rules and Basics
Check
Definition
Check is the state where the king is attacked by one or more opponent pieces and must be defended on the next move. The player whose king is in check has three response options: move the king to a safe square, block the attack path with another piece, or capture the attacking piece.
Usage and Example
When you check the opponent king, notate with "+" (example: Qh5+). Check with no escape is called checkmate.
Grandmaster Tier Context
T1 Beginner. First concept learned after basic piece moves. A 6-year-old typically grasps check after 2-3 training sessions.