In chess, an illegal move is a move that is not allowed according to the rules of the game. There are several types of illegal moves that can occur in chess, including:
Moving a piece to an occupied square: In chess, it is not allowed to move a piece to a square that is already occupied by one of the player’s own pieces.
Moving a piece to an illegal square: Some pieces, such as knights, have special movement patterns that allow them to move to certain squares that other pieces cannot reach. If a player tries to move a piece to a square that it is not allowed to reach, this is considered an illegal move.
Leaving the king in check: In chess, it is not allowed to leave the king in a position where it can be captured on the following move. If a player tries to make a move that would leave the king in check, this is considered an illegal move.
Making a move that puts the king in check: In chess, it is not allowed to make a move that puts the player’s own king in check. If a player tries to make a move that would put their own king in check, this is considered an illegal move.
Making a move with the intention of repeating the same position: In chess, it is not allowed to make a move with the intention of repeating the same position that has occurred three times in the game. If a player tries to make a move that would result in the same position being repeated three times, this is considered an illegal move.
In conclusion, an illegal move in chess is a move that is not allowed according to the rules of the game. There are several types of illegal moves that can occur in chess, including moving a piece to an occupied square, moving a piece to an illegal square, leaving the king in check, putting the king in check, and repeating the same position three times.