The corresponding rook moves two spaces to the other side of the king. The requirements and restrictions on castling are per normal chess. Sliding the king's rank does not negate the possibility of castling. Missing Spaces Pieces cannot occupy or move past missing spaces, such as a2 and h5. Missing spaces do not block diagonal movement.
Knights leap over missing spaces.
A rook could never move from a1 to a3 because there is never a space at a2. A bishop could move from a1 to b2 and a knight could jump from b1 to a3, assuming neither destination square was occupied by a friendly piece. You control a rank if the majority of pieces on the rank are yours. If both players have an equal number of pieces on the rank, the rank is uncontrolled. If you wish to slide an uncontrolled rank, you must first ask your opponent's permission.