Is castling a king move or a rook move? Most computer chess games consider castling to be a king move. You click on the king and it shows an option to castle.



What do the FIDE's rules say about this though? Is castling a king move, a rook move, both, or neither?
The FIDE rules say this about castling:


  This is a move of the king and either rook of the same colour along 
  the player’s first rank, counting as a single  move of the king