Rules of Castling

Castling is a special rule only for King and Rooks. There are 2 ways of castling:

King-side castling - with King-Rook

Queen-side castling - with Queen-Rook

King --> moves 2 squares

Rook --> moves to the other side of the King

Rules

1. The King and castling Rook should not have moved in the game before.

2. There should not be any piece in-between the King and castling Rook.

3. When Check is given, you cannot castle.

4. If the King would come in Check after castling, you cannot castle.

5. If the King would come in Check in-between castling, you cannot castle.

Castling on Wiki