Castling
Also called O-O, O-O-O, Castle.
The king moves two squares towards a rook, and the rook jumps over to the other side, in one move.
Allowed only if neither piece has moved, the squares between them are empty, the king is not in check, and it does not pass through or land on an attacked square. Only the king’s squares matter; the rook may cross an attacked square, such as b1 when castling long. Short castling is written O-O, long castling O-O-O.
Castling counts as a king move. Over the board, touch the king first; online, drag the king two squares.
Want more? Puzzles on this from real games, on Lichess, free and with no account. They are not counted in your progress here.
Learn and practise it
- Lesson: Castling