How do I castle?

Move the King two squares towards the Rook.
Castle                    example
Above, the "short castle" (castle with the King's Rook) is shown. There is another castle move, the "long castle", which involves the Queen's Rook. In the long castle move, the King also moves by two squares (and the Rook travels a little bit more).

If the castle move is legal, the Rook will also move.

Castle                    example
The position after the short castle is shown above.

Please read carefully the rules, they explain when a castle move is possible and when it is not.

If CHESS refuses your castle move, then you can be certain that it is not legal at the moment you play it. The rules will tell you why.


  • You cannot castle when you are in check (when your King is under a direct attack).

    Illegal castle example
    You will be able to castle when you are not in check anymore (and if you don't move your King).

  • You cannot castle if your King moves to a square where it is attacked, or even just walks on a square where it would be attacked.

    Illegal castle example

    Illegal castle example

  • You cannot castle if either the King of the Rook have already moved (even if they are now back on their original squares).

The idea is that castling is only allowed as a quiet development move in a quiet position.