What rules (if any) cover a situation like this?
3.10.2 of the FIDE Laws of Chess defines when a move is illegal -
3.10.2 A move is illegal when it fails to meet the relevant requirements of Articles 3.1 – 3.9
Articles 3.1 - 3.9 basically describe the moves of the pieces. Inarkiev's move was illegal because it breached 3.9.2 -
3.9.2 No piece can be moved that will either expose the king of the same colour to check or leave that king in check.
3.10.3 defines when a position is illegal -
3.10.3 A position is illegal when it cannot have been reached by any series of legal moves.
After Inarkiev made his illegal move the position was illegal because his king was in check and it was not his turn. After Carlsen made his (perfectly legal) move the position was legal again because Inarkiev was in check and it was Inarkiev's turn. Inarkiev was wrong to stop the clocks and claim an illegal move. The first arbiter made a mistake. Presumably Inarkiev said that Carlsen had made an illegal move and the arbiter took his word for it without checking - very unprofessional.
Article 7.5.1 defines when an illegal move has been completed (different from "made") and what should happen next in standard play games -
7.5.1 An illegal move is completed once the player has pressed his clock. If during a game it is found that an illegal move has been
completed, the position immediately before the irregularity shall be
reinstated. If the position immediately before the irregularity cannot
be determined, the game shall continue from the last identifiable
position prior to the irregularity. Articles 4.3 and 4.7 apply to the
move replacing the illegal move. The game shall then continue from
this reinstated position.
The same definition for the completion of an illegal move applies to rapid and blitz however the way the illegal move is handled is different unless certain strict conditions apply.
In blitz illegal moves are handled like this (i.e. "Competition Rules apply") only if -
B.3.1 The Competition Rules shall apply if:
B.3.1.1 one arbiter supervises one game and
B.3.1.2 each game is recorded by the arbiter or his assistant and, if possible, by electronic means.
With 69 games they would need 69 or more arbiters. I don't believe they had that so according to B.4 Rapid rules apply -
B.4 Otherwise, play shall be governed by the Rapid chess Laws as in
Article A.2 and A.4.
The relevant article is A.4.2 -
A.4.2 If the arbiter observes an illegal move has been completed, he
shall declare the game lost by the player, provided the opponent has
not made his next move. If the arbiter does not intervene, the
opponent is entitled to claim a win, provided the opponent has not
made his next move. However, the game is drawn if the position is such
that the opponent cannot checkmate the player’s king by any possible
series of legal moves. If the opponent does not claim and the arbiter
does not intervene, the illegal move shall stand and the game shall
continue. Once the opponent has made his next move, an illegal move
cannot be corrected unless this is agreed by the players without
intervention of the arbiter.
So, the sequence of events was -
- Inarkiev makes an illegal move
- Neither the arbiter nor Carlsen spots it and Carlsen makes a legal move.
- Inarkiev incorrectly tries to claim the game.
- The arbiter who deals with it incorrectly believes Inarkiev without checking and awards the game to Inarkiev.
- The Chief Arbiter correctly overturns the decision and rules that Inarkiev must make a move in the position in which he made his incorrect claim.
I don't know if the Chief Arbiter did this but in his position I would also award Carlsen an extra minute on the clock in accordance with article B.2.
B.2 The penalties mentioned in Articles 7 and 9 of the Competition
Rules shall be one minute instead of two minutes.
EDIT: Checking on the FIDE web site I see that they have published the regulations for the World Rapid and Blitz Championships which confirm that Rapid rules apply in the case of illegal moves -
6.14 Tournaments will be played according to the rules of the inadequate supervision of the Rapid play Laws of Chess (FIDE Handbook,
E.I.01B Appendices, art. 1 to 4). In addition, if a player displaces
the pieces during the game: for the first time he receives a warning
but for the second time he will be forfeited.
EDIT2: Perhaps I should just also point out for anyone reading this after 1st Jan 2018 that FIDE are unhappy with the "one illegal move loses in rapid and blitz" rule and this is changing from 1st Jan 2018. The new rules have a new article A.4.2 -
If the arbiter observes an action taken under Article 7.5.1, 7.5.2,
7.5.3 or 7.5.4, he shall act according to Article 7.5.5, provided the opponent has not made his next move. If the arbiter does not
intervene, the opponent is entitled to claim, provided the opponent
has not made his next move. If the opponent does not claim and the
arbiter does not intervene, the illegal move shall stand and the game
shall continue. Once the opponent has made his next move, an illegal
move cannot be corrected unless this is agreed by the players without
intervention of the arbiter.
This basically says that in the case of an illegal move in "unsupervised" rapid and blitz the rules regarding when an illegal move is spotted and handled remain the same (if neither the players nor the arbiter spot it and stop the game then the game continues) but the penalties are as in standard play with a time penalty and restored position in case of a first offence and losing the game in case of a second offense.