Castling might be one of the weirdest chess rules in existence. Not only is it the only way to play two pieces at the same time (♔ king and ♖ rook), it’s also the only move where the king is allowed to take two steps in a single turn.
Following the rules of chess, the king is allowed castle to both sides (left or right). A long castle move is referred to as castling queenside, a short castle move is referred to as castling kingside. Both the king and rook always move horizontally from their initial board positions.
Each player can only castle once per chess game. Please note that a castle move to either side on the board isn’t always possible. For the special chess move to be considered legal, the following conditions should be met (learn more about them here):
- Both the king and rook may not have moved from their starting positions;
- The king may not be in check;
- None of the squares the king moves through may be under a check threat;
- No pieces may stand between the king and rook.
Castle To Both The Left And Right Side
Setting up the board for a defensive castling move is a clever strategy at the beginning of the game. Because the game of chess includes a set of two rooks, it follows that a choice can be made. Do you want to castle to the left side, or the right side?
Both sides can be equally rewarding. Whether you free up space on the left side or the right side does not matter much. Castling is allowed in either horizontal direction (vertical castling is not allowed). Usually, the board situation will only allow for castling to one of the sides.
Players can choose to intentionally free up space for the king and rook to switch sides — either on the queenside or kingside. The rook on the side of the queen makes a ‘long castle move’, while the rook nearest to the king is the ‘short castle move’.
Short Castle Move: Kingside
The most common castle move is the shorter version, which switches the rook and king on the king’s side of the board. We refer to this as a castling move on the kingside. The short castle move is easier to perform, as only two pieces (the ♗ bishop on f1 and the ♘ knight on g1) need to be removed to execute it.
The main benefit of short castling is the slightly better protection the king would have at board position ♔ g1 for white, or ♚ g8 for black, compared to the slightly weaker position for the queenside or long castle move.
The biggest drawback of short castling is the fact that the rook usually isn’t activated that well (in order to attack or provide cover for other pieces). The rook on the kingside can’t move as easily as the queenside rook could after a long castle move.
That said, the short castle move on the kingside would look similar to the steps shown in the image below:
Long Castle Move: Queenside
Less common is the long castle move, or castling on the queenside. This requires a player to remove a total of three pieces from their starting position. For white, the ♕ queen on d1, ♗ bishop on c1, and ♘ knight on b1 would need to move first. This is a major drawback that makes queenside castling a bit weaker than kingside castling.
At the same time, the king’s protection on c1 is slightly weaker than it would have been after a short castle move. We could argue that the better board development of the other pieces compensates for this.
Displacing three other pieces takes at least one turn longer, making it slightly more difficult to execute the long castle move. However, the benefit is that you now have three strong pieces developed on the board. Actually make that four strong developed pieces, when you include the ♖ rook that moves from a1 to d1.
For white, the queenside or long castle move could look similar to the situation on the image below:
Kingside vs. Queenside Castle
Comparing the kingside with the queenside castle move, there really isn’t a major winner. Both are good in their own way, and both are slightly weak in their own way.
A kingside castle move is fast and defensive for the king. But it doesn’t develop the rook very well. A queenside castle move is slower and more offensive overall, developing a lot of pieces on the board. But it doesn’t protect the king in the best way.
If you’re a defensive player, aim to castle kingside. If you choose the offense in the early game, queenside castling is your main weapon. However, it will also depend on the options you have on the board. The opponent can deny you the opportunity to choose, by putting immediate pressure on either one of the sides.
Also remember that the more offensive play (queenside castle), takes at least one turn longer to pull off. That is precious time in the early game. It could mean that the opponent gains a competitive advantage in the late early game or midgame. You would need to make up for that with your board development sooner rather than later.
What is your personal preference, kingside or queenside? And what made you choose that? Let me know in the discussion below. This will give other readers a better insight into the moves that are best for them. Happy castling!