What are the examples of illegal chess moves? With helpful videos!

illegal chess move

So, what happens when you make an illegal move? I always wanted to know what are the illegal chess moves according to some official rules.

I have committed illegal moves myself and experienced playing with chess players who made an illegal move, but the problem is sometimes both of you don’t have an idea that it was an illegal move.

What will happen is we’ll not be informed and might commit the same mistake over and over again till someone knowledgeable about the illegal moves in chess will finally correct you.

That is why in this article, I wanted to share with you a sort of guide about illegal moves in chess so you will have a piece of general knowledge and avoid these moves while playing an actual game of chess.

What are the illegal chess moves you should know?

Not all irregularities make-up illegal chess moves

The first thing to say is that not everything that is done wrong in a game of chess is an illegal move. Countless irregular situations can happen; players can make involuntary mistakes due to distraction or ignorance. There can also be situations where a chess player acts with negligence or bad faith, but all this is not synonymous with illegal play.

Illegal moves are a few situations that are defined explicitly in the FIDE Laws of Chess. Also, currently, a couple of conditions specified in the Interpretations of the Referees Commission and the FIDE Regulations Commission must be added.

Currently, any of the following situations are considered illegal play in chess:

A movement that does not meet the relevant requirements of Articles 3.1 to 3.9 (Article 3.10.2)

  • Any play where a piece is moved with an inappropriate movement (for example, moving a Knight as if it were a Bishop).
  • Moving a piece to a square occupied by another piece of the same color.
  • Moving a piece to a square occupied by an opponent’s piece and not removing the board’s captured piece.
  • Moving Bishop, Rook, or Queen is passing over other pieces.
  • Move a pawn to the last row, and do not replace it with another chess piece.
  • Moving a pawn to the last row and replacing it with any object that is not a Queen, Rook, Bishop, or Knight of the same color as the Pawn.
  • Make a move leaving your own King in check.
  • Castling when it is not valid to do so (because the King or the Rook with which he castled has moved, the King is in check, there are pieces between the King and the Rook, or the destination square or one of the squares is attacked through which the King must pass).

Move a pawn to the farthest row and press the clock without having replaced the pawn with a new piece (Article 7.5.2)

If the game continues (first illegal in classical chess), the referee will replace the pawn with a queen of the same color (the offender loses the right to choose the crowning piece).

Use both hands to make a move in case of castling, capture, or promotion (Article 7.7.1)

For the first offense, the arbiter will grant two minutes of extra time to his opponent. If the same player commits a second infraction of Art.7.7.1, the arbiter will declare the game’s loss for the offender. However, the arbiter will call a draw if the position is such that the opponent cannot checkmate the offender’s King by any legal series of moves. (Art. 7.7.2).

Pressing the chess clock without having performed a move (Article 7.8.1)

For the first offense, the arbiter will grant two minutes of extra time to his opponent. If the same player commits a second infraction of Art.7.8.1, the arbiter will decree the game’s loss for the offender. However, he will call a draw if the position is such that the opponent cannot checkmate the offender’s King by any legal series of moves (article 7.8.2).

Capture the opponent’s King (Point 4 of the Interpretations of the Referees Commissions and Regulations)

Any other situation that is not one of those described above does not constitute an illegal move.

If a player makes a play with one hand and presses the clock with the other, it is not considered an illegal play (Point 9 of the Interpretations of the Referees and Regulations Commissions)

What happens when illegal chess moves occur?

Illegal chess moves are completed once the player has pressed the chess clock (Article 7.5.1)

Due to this article, a player who has made a move that will set up an illegal move, but realizes it before pressing the clock, still has time to correct it. For example, a chess player moves a Knight as if it were a Bishop but realizes before pressing the clock; he can retake the Knight and move it correctly.

It often happens (usually in blitz games) that a player makes a move that when he presses the clock will become an illegal move, but the opponent does not wait and signals the illegal move before pressing the clock. There was still no illegal play at that time, and the player who made a mistake is in time to correct the movement as long as he has not pressed the clock.

Having read the two preceding paragraphs, indeed, someone may be questioning what was said because if a player dropped the piece in a square, there is no longer any possibility of moving it to another square. But let’s see what the Laws of Chess say about it: 

“When a piece has been dropped on a square, as a legal move or part of a legal move, it cannot be moved to another square on this move” (Article 4.7).

The key is that in the situation we are describing, the piece has not been released as a legal move or part of a legal move; therefore, as long as the clock has not been pressed, it can still be moved to another square.

Even more, there is supposed that a player moves a piece that does not have any legal movement available (for example, a Knight that is pinned because if it were moved, it would leave the King himself in check). If the player becomes aware after moving the piece but before pressing the clock, he can return to leave the piece moved in the square it occupied before moving it and move any other piece that can be legally moved.

In the previous case, the well-known rule that the touched piece is a moved piece is not being violated, since what the Laws of Chess say in this regard is that if the player in play touches one or more of his pieces on the board, he must mobilize the first piece touched that can be moved (Articles 4.3 and 4.3.1), and that if none of the pieces touched can be moved or captured, the player might make any legal move (Article 4.5).

Wrapping Up

A piece of simple advice regarding not knowing if a move is a legal or illegal move is never to commit that move without asking or researching first.

Your knowledge of illegal chess moves will slowly increase that you don’t have to keep on asking an arbiter or someone you know is knowledgeable than you in chess.

In any other case, you can always refer to this article or even share this article with your friends who might have a question or you think have committed an illegal chess moves.

If you still have any doubt, I will be adding articles, videos that I think is very useful, and an official handbook below where you can read and refer to answers to your illegal chess move questions:






I hope you enjoyed this article! Enjoy learning about illegal moves in chess!

Gary Flores

Hi there! I'm a dad with kids who loves to learn how to play chess by learning online - also, this is my way of refreshing my knowledge about this game of tactics & strategy. I created chessdelights.com to inspire people who are also learning, re-learning or teaching their kids the game of chess.

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