I heard that they lose some time or that they lose the game. I'm not sure what happens.

2 Answers 2


By the FIDE Laws of Chess, article 7.4:


  • a. If during a game it is found that an illegal move, including failing to meet the requirements of the promotion of a pawn or capturing the opponent’s king, 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. The clocks shall be adjusted according to Article 6.13. The Articles 4.3 and 4.6 apply to the move replacing the illegal move. The game shall then continue from this re-instated position.
  • b. After the action taken under Article 7.4.a, for the first two illegal moves by a player the arbiter shall give two minutes extra time to his opponent in each instance; for a third illegal move by the same player, the arbiter shall declare the game lost by this player. 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.

That is, on the two first illegal moves of your opponent, you gain time on your clock (two minutes, which likely does nothing), but on the third illegal move of your opponent, they lose the game (unless it was already impossible for them to lose it).

  • 5
    As a corollary: Stop the clock, get the arbiter. Always get the arbiter in the case of a dispute.
    – kahen
    Sep 24, 2014 at 1:38
  • 2
    And of course, those rules are only valid for long time controls (standard), for short time controls other rules apply, see the appendixes. Sep 24, 2014 at 5:47
  • 1
    It is important to note that touch-move rule still stands, as explained in Article 4.3, which is referred to in the quote. (I've won at least one game when my opponent didn't notice he is in check, moved his rook, and was so unlucky that the rook had one legal move to an unprotected square blocking the check.)
    – JiK
    Oct 2, 2014 at 9:02
  • "but on the third move you lose the game (unless it was already impossible for you to win it)." Shouldn't that be "unless it was impossible for you to lose it"? Feb 1, 2021 at 2:25

When it comes to Blitz games (5 minutes or 3 minutes + 2 seconds) first illegal move loses the game on the spot. Other solutions (like adding 2 minutes) would lead to total confusion.

Keep in mind, after your oponent has made an illegal move, you are obliged to:

  • stop the clock
  • call the arbiter
  • explain what happened

(btw, you must have time on your clock, if you are already at 0:00 then you can't do anything)

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