Checkmate

Checkmate occurs when a king is in check and no legal move can remove the attack.

Checkmate ends the game immediately. The king is not captured or removed from the board.

Checkmate requires check and no legal reply

A position is checkmate only when the king is attacked and every legal response fails. If the king can move, the attacker can be captured, or the line can be blocked, the position is check rather than checkmate.

Move the black queen from d8 to h4 to deliver checkmate.

After 1.f3 e5 2.g4, Black can end the game with Qh4#.

The game ends before the king is captured

Chess rules do not continue to a king capture. The checking move ends the game as soon as checkmate exists, and the player who delivered mate wins.

Qh7#: The hash marks checkmate in SAN.

Checkmate, stalemate, and resignation differ

Stalemate has no legal move but no check, so it is a draw. Resignation is a player's decision to concede before the board itself reaches checkmate.