And of course, this move works the same for black. Then you may not castle to the king-side, because you would be moving your king over a square where he would be in check. White may not castle king-side here because your king may not move over a square that would be check. There is one more condition: You may not do this move if your king moves over a square where he would be in check. However, if you didn’t move the king when you were in check, for example if you blocked the check with a piece, then you would still be allowed to do the castling move later on. The third condition is that you may not do the move if your king is in check. Even if he went here and later moved back, he may still not do the move since he has already moved. If your king has already moved, then you can’t do the move anymore. If this rook already moved earlier on in the game, then you are not allowed to make the castling move with it, but you could still do the move with this rook, provided it hasn’t moved as yet. Secondly, you may only castle if your king, and the rook you want to castle with, have not moved since the start of the game. The first condition is that you may only castle if all the squares between the king and rook are open. So now you know how the castling move works, but you also need to know all the conditions that allow you to castle. And for this very reason, castling is also sometimes referred to as “building a castle”. The second reason is that it helps your king to be in a safer position and move away from the middle of the board. The first reason is that it helps your rook get out of the corner and get closer to the middle of the board where there is usually more action happening. There are two reasons why castling is a good move. If you castle on the queen-side, then it’s known as queen-side or long-side castling.
If you do the castling move on the king-side, then it’s called king-side or short-side castling. If there is an open space between the king and this rook, then you can move your king two square and the rook hops over.