# 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?

• As far as I know, you should touch king first. Touching rook against moron could lead to moves like Rg1 or Rf1. Jun 2 '17 at 4:19
• Why don't you read the laws first? It is pretty unambiguous on this one. Anyway, DM answered your question. Jun 2 '17 at 9:27
• If it wasn't counted as a king move, maybe you could castle twice. Jun 2 '17 at 13:14
• In a tournament a couple of years back my opponent's king moved to f7 and back to e8. He then tried to castle, illegally, and because castling is a move of the king the arbiter required him to move his king. There was only one possible square, and this dropped his other rook. Feb 23 '18 at 14:45
• I once lost a game because I touched my rook first and opponent called the arbiter. Apr 21 '19 at 3:45

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

• Strange definition: This is a move of the king and...rook..., counting as a move of the king. Does this "counting" only apply to the touch-move rule or to anything else? Jun 2 '17 at 8:20
• "Counting as a single move of the king" applies to everything of course. Castle is a king's move that's it. It does involve two pieces but that is the same as capturing a piece or promoting a pawn these moves also involve two pieces but they are single moves of only one of them. Jun 2 '17 at 9:33
• @IAPetrHarasimovic What do you mean by "everything". Or asked differently: If this rule did not exist, how would this change chess? Jun 2 '17 at 10:44
• @user1583209 You must touch and move the king first.
– Paul
Jun 2 '17 at 16:48
• I'm not 100% sure about the proposed edit - especially the part where "This is for sure the reasons why many sites and apps show Castling available only when selecting the king not the rook.". Honestly, the programs are probably written that way because it's unambiguous, not because of FIDE touch-move rules that don't really apply to programs anyway. If you move your king two squares, that's obviously a castle. But if you move your rook to f1 or d1, that's a perfectly legal move - how would the program know whether you wanted to castle or just move the rook?
– D M
Jun 2 '17 at 18:52

Castling is a combination move of both pieces. The king should be moved first or both pieces simultaneously, since a rook move could stand alone and an opponent might make you stop your move at that point as being "legal", not letting you complete castling.

As a purely separate thought on the stupidity of the current rule consider the following hypothetical case: White can castle, but both the f- and h-files are open. White plays Rf1, suddenly realises he has missed a much stronger move and quickly moves his king to g1 . As the rule stands his opponent or, as happened in a recent Soviet event, the arbiter can insist on a rook move. White calmly plays the winning Rh1-h8.

• Rather seems like an incorrect application of the rules to me. In addition to "touch-move", there's the little brother rule that says that if a player let's go of a piece, the move is completed and he can't retract that move (if it was legal), period. If White has let go of the rook on f1, then nothing that happens with the king afterwards changes the fact that he has just played Rf1. He might as well put his king on a1 before pressing the clock (another illegal action)... Rf1 stands. Feb 23 '18 at 12:45
• By the way, "recent Soviet"? 28+ years is not "recent". ;) Feb 23 '18 at 12:45
• Formerly the arbiter only gave a warning when a player had castled incorrectly. Since the FIDE congress of Thessaloniki 1984 a player is punished with an obligatory move with the rook with which he wanted to castle. Feb 23 '18 at 14:50