When a player castles in chess, it’s the only opportunity to move two pieces at the same time. In addition, castling allows the King to move more than one space at a time and also to jump over another piece.
When a player is new to chess, castling seems to be an illegal move. The King moving two spaces and two pieces moving at the same time seems far out of regular gameplay rules.
Can a player castle in chess? Yes, and no. A player cannot castle when the King or Rook have already made a move. However, the player is allowed to castle whenever their Rook piece is under attack or remains in line of attack after the castle is complete.
According to the basic rule of chess, a player can only move a single piece in turn, but not with castling. Castling acts like a strategic tool a player may use to protect their King and at the same time develop their Rook.
With castling, a player can move their King over two squares, either left or right. At the same time, the Rook moves to the opposite side of the King.
When castling happens, the King is transferred from the starting square it occupies two squares over, either to the left or right, towards the square occupied by a Rook piece. Then, the Rook is transferred to the opposite side adjacent to the King.
This article discusses everything you need to know about castling in Chess. Answered below are frequently asked questions about being able to castle in chess, and what circumstance prevent this seemingly illegal move from happening.
What are the four rules for castling in chess?
A player can’t castle at any time they feel like, there are specific limitations and rules for the move. The following are four major rules that a player must adhere to before castling a King.
- King cannot castle when it has already moved. Once the King makes a move, the King cannot castle, even if it returns to the starting square. Most players use strategy to force the opponent King to make a move just to prevent the King from castling.
- Rook should not have made a move prior to castling. If a player moves their Rook, then a player cannot castle with a King on that side. Both the King and Rook should not make a move prior to castling.
- King can’t be in check. In chess, castling can seem to be an escape route, but the player cannot castle when their King has been checked. Once the player’s King is out of check, then a player can castle.
- Furthermore, the King cannot castle into check. If by any chance a King will land into a square which will put it under check after castling, then a player may not castle. In contrast, a Rook can castle into a position where it is under attack.
- It’s important to also note that castling is not allowed until the squares between the King and Rook are empty. Meaning the Bishop, Knight and Queen must move to clear the lane for a castle to be executed.
When can I castle?
The King and Rook cannot move from their starting position, no pieces can be in-between the King and Rook, and the King cannot be in check or move into a position of check.
Here is a bit more detail about the following circumstances:
- When the King has not been moved, once the player King moves, it losses its ability to castle during the game. Even if the player moves the King back to its initial square, as long it moved then it can’t be castled.
- If the Rook has not been moved, the King is allowed to move across to the Rook’s side. However, if the Rook has already moved, the King cannot move on that side, but has the option to castle on the other side if that Rook has not yet moved.
- When the King is not in check. Though castling appears as if it is an escape strategy, it cannot escape a check. When the King is out of check, the King can still castle since it doesn’t lose the ability.
- A player can castle if they do not land the King into a square resulting in a check.
- When there is no other piece between the King and the Rook, a player can castle around the space when all the spaces between a King and the Rook are empty.
What is illegal castling in chess?
The King cannot castle when in check, if the King or Rook have previously moved during the game or if their are piece in-between. The King cannot move into check, but the Rook can move into a position under attack.
The following are circumstances under which castling a King is considered an illegal move in chess.
- Once the player’s King is in check, it cannot castle until it is out of check. Therefore, castling cannot be used to escape a check.
- Once the Rook has been moved, the King cannot castle on that side.
- King can’t castle once it has already moved, even if the King is returned to its original square.
- The player can only castle when the spaces between the King and Rook is empty.
- The King and Rook cannot be un-castled. Castling is only in one direction, there is no reverse for the move.
How to Castle
There are two ways to castle, Kingside and Queenside. In both circumstances, the King moves two squares in the direction of the Rook, and the Rook moves to the square adjacent to the King on the opposite side.
In Kingside castling, the player has to move a King two spaces to their right or the left. If it’s a White King, it has to move to the right and the Black King to the left.
Once the King moves the two spaces, the Rook moves to the opposite side next to the King.
Queen castling is the same as that of the Kingside, only that the White Queen has to move to the left and the Black to the right. The King moves two spaces in the direction of the Queenside, then the Rook flips to the space next to the King.
For both castling, the Rook has to jump over the King, and by doing so, it settles adjacent to King on the opposite side that it started on. Any time a player castles, the player has to move their King two space, and the Rook positions according to the King.
Castling in Chess: Conclusion
Castling brings about a major exception when it comes to the rules of playing chess.
In a single move, a player must move only one piece at a time. However, with castling, a player can move two pieces at the same time.
It’s an essential strategy that a player can use to both protect their King and develop the Rook at the same time.
Castling, in simple terms, involves moving a King two squares either to the left or right. The Rook is then moved on the opposite side of the King for the castle to be complete.
A player should always move the King two spaces to either side before picking the Rook. For that to happen, there should be no other pieces between the Rook and the King.
More so, both the King and the Rook must not have moved before the castle is attempted. If none of the above has been fulfilled, the castle will be considered illegally and should not be allowed to happen.
In chess, when a player castles, it’s the only time a player can move two pieces simultaneously. Castling can be done on the Kingside or Queenside. When done through a King, the white King has to move on the right while the black King has to move to the left.
Queenside castling is similar to that of the King, and the only difference is that the white color King has to move on the left and right for the black color chess pieces.
If no piece are in-between the King and Rook, neither piece has been moved since the start of the game, and the King is not in check and will not be in check after castling, then the move can be done legally without any concern.