Castling is a special move in chess where the rook and king are moved together. They don’t exactly swap places, but they come close. They switch, with the king moving to the side of the board and the rook moving more to the middle.
Castling can be done on both the king and queen side of the board.
How to Castle in Chess: Swapping the Rook and King
To castle, the king is moved 2 squares toward a rook and the rook is placed on the other side of the king. As there are two rooks, you can castle to either side. Here’s a visual on castling king side:
As you can see in the first picture, the king moves 2 squares toward the rook. The rook is then placed on the other side of the king, right next to it. The king ends up 1 square away from the edge. Here’s a visual for castling on the queen side:
The king does the same thing on the queen side, moving 2 squares toward the rook. The rook is then placed on the other side of the king, right next to it. The king ends up 2 squares from the edge of the board. (more on queen side castling)
Here are the requirements for castling:
- The king has not been moved during the game, so it’s in its original spot (setting up the board).
- The rook on the side of the castling has not been moved during the game either.
- The squares between the king and rook are all empty (bishop and knight on king side/queen, bishop and knight on queen side).
- The king is not in check, won’t have to pass through check, and won’t end up in check when the move is complete.
If you have any more questions about castling, check out the castling FAQ.