Chess Rules: When You Can (And Cannot) Castle

Chess isn’t as complicated to learn as many people believe that it is. However, there are a small handful of “special moves” that can be a bit confusing for the new player and one of those moves is castling. Many newer players find it hard to track when they can castle and when they can’t..

For many players one of their earliest tactical objectives is to open up their position enough that they can move the king to safety through castling and it’s important to understand how this critical process in chess really works. You can only castle once during a game, and it’s the only time that the king can move more than 1 square at a time.

Here’s are some handy guidelines about the rules of castling in chess.

Chess rules: When you can and cannot castle - ChessPulse.com
Chess rules: When you can and cannot castle – ChessPulse.com

The Four Key Rules For Castling In Chess

Castling is a move that allows you to move both the king and one of your rooks at the same time in a game. It requires you to move the king towards the rook, 2 spaces rather than the usual single space and then to move the rook around the king to the square adjacent to the king on the opposite side of where the rook started.

Castling is dictated by four key rules in chess and these are:

  • Neither the king nor the rook may have moved from their starting position at any time in the game prior to castling.
  • There must be no pieces in between the rook and the king of any color.
  • The king must not be in check.
  • None of the squares that the king passes through, including the starting and finishing square, may be under attack by any of the opponent’s pieces during the time of castling.

Castling is not a traditional chess move. It appears to have been injected into the game in Europe during either the 14th or 15th century A.D. Asian variants of chess, which evolved prior to this, don’t have a form of castling. It wasn’t until the 17th century that European chess had codified the rules of castling as above and there are forms of castling in old games that were different to this.

The Tournament Rule Of Castling

One thing that you should be aware of is that castling is considered to be a king move. That means if you are playing a game under strict “touch a piece, move a piece” rules, if you want to castle, you must touch the king first and move it first.


Note, however, that most official tournament rules are much more forgiving than this and if you were to touch the rook first, you would still be allowed to complete the move. It’s good practice to touch the king first in any case.

There is also a rule that requires you to complete the entire move only using the same hand to touch each piece. This is only ever enforced in competitive chess (and rarely even there) most players don’t even know that this rule exists if they don’t play in competitions.


How Many Times Can You Castle In Chess?

The first rule of castling is “neither the king nor the rook may have moved from their starting position at any time in the game prior to castling.”

So, how many times can you castle in chess? You can only castle one time in a game. This is because the act of castling moves both the king and the rook and if the king has moved, it may not castle.


Can You Castle Anytime In Chess?

Yes, you can castle any time in chess. Though you must still satisfy all four key rules of castling which means, for example, that you could not castle on the first move of the game because there would be material between the king and the rook on either side of the board.


Can You Castle On Both Sides?

Yes, you can castle on both sides but since you can castle only once in a game, you must choose a side to castle on for that one game. It is worth noting that the king travels no farther when castling to the queen’s side than when castling to his own side. Thus, castling to the queen’s side can leave the king slightly more vulnerable to attack.

The notation for castling is the same in both the algebraic form of notation (which is the grid reference style of notation that you will find in common usage on this website) and in the descriptive notation (which describes moves in relation to the original piece on the first row and which is considered somewhat archaic now).

If you castle to the king’s side, then you would put 0-0 on your score sheet. If you castle to the queen’s side, then you would write 0-0-0. This is because neither notation system can neatly document the movement of two pieces in a single move and given that it only happens once per game – it’s easier to accommodate with a different notation than to change the rest of the system.

Queen’s side castling is sometimes referred to as “castling long” because the rook moves a longer distance and yes, king’s side castling can be called “castling short” too.


Can You Castle Out Of Check?

No. You can not castle out of check. One of our four key rules of castling is, “none of the squares that the king passes through, including the starting and finishing square, may be under attack by any of the opponent’s pieces during the time of castling.”

In this case, the starting square would be under attack by the opponent’s piece and thus, you can’t castle out of check and nor can you castle “through” check or “into” check.


Can You Castle If The Rook Is Under Attack?

Can you castle if the rook is under attack? Yes, you can. There is no rule that states your rock cannot be under threat when you initiate castling. However, it’s worth noting that if the rook is under attack, you might want to be careful about moving your king closer to a threat. In general, most people castle to protect the king rather than to throw it into the opponent’s firing line.


Can You Castle After Being In Check?

Yes, you can castle after being in check. However, it is important to note that this is only true as long as you have not moved the king or the rook to get out of check. There are no rules of castling that specify the king can’t have been in check but there is one forbidding the pieces involved to have moved (and no,  you can’t move them back to the starting square and then pretend that they never moved).


Can You Castle Back In Chess?

You can’t castle back in chess. Castling is a one-time and one-way special move in chess. It’s meant to keep the game interesting and ensure that the first time your king falls under attack that it has somewhere to run. It’s not meant to see your king shuttling back and forth like a yo-yo which would make it very difficult (if not, perhaps, impossible) to reach a checkmate.

This means that a good player will use their chance to castle wisely – ideally, it will help to defend the king, moving it away from the opponent’s main line of attack and, at the same time, it will help to open up the offensive power of the player’s rook which can be a very powerful piece.


Conclusion

Castling is a “special move” that falls outside of the standard moves of a piece and by definition, given that you cannot castle after moving either the king or the rook involved in the move, you cannot castle more than once as doing so involves moving the king.

You can, however, castle at any time in a chess match as long as you have the space to do so and are not castling through check and haven’t moved either piece beforehand. You can cast on both sides and yes, you can castle if the rook is under attack. You may also castle if your king has been in check, but you may not castle out of check or through it. Finally, castling is a one-way deal – you can’t castle back if you don’t like what you find.

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