Illegal Moves In Chess: Everything You Need To Know

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Other than playing casually, if you play formal chess games then you may have heard about ‘Illegal moves’.

But do you know what it actually means? What happens when you make it? What are the examples of illegal moves?

All these and some other related questions will be discussed in this article. So if interested, keep reading till the end!

What Is Considered An Illegal Move In Chess?

An illegal move is any move that violates the standard rules of chess. Moving a king into check, touching a piece but moving a different piece, and using two hands to castle, promote or capture a piece, are some of the examples of illegal moves in chess.

The World Chess Federation also known as ‘FIDE’ is the international body that governs all the chess competitions and rules, and regulations.

The standard rules of chess are generally followed as mentioned in the FIDE Laws OF Chess handbook.

Now in that, there is a complete description of how to move chess pieces, how to castle, how to promote a pawn, how to behave while playing, and all other necessary things.

So if any of the players go against these standard rules and make a move then that is said to be an illegal move.

Now you may think what will happen if I make an illegal move, right? Let’s discuss that!

What Happens When You Make An Illegal Move In Chess?

As per the standard rules of chess, when a player makes an illegal move for the first time, the opponent is allotted two minutes extra time (one minute in Blitz). But for the second time, the player loses the game. However, if the opponent has insufficient mating material then the game is drawn.

In the FIDE laws of chess article 7.5.5, there is a clear description of this thing. You may be confused about insufficient mating material.

In simple words, insufficient mating material as the name suggests means the player doesn’t have enough pieces to checkmate the opponent’s king by any series of legal moves.

The game is drawn in such a case. Just imagine that you made an illegal move for the second time.

So as per the rules this time you should lose but the position of the board shows that you have a king while your opponent has one king and one knight. Then in this scenario, the game is drawn.

This is because although you made an illegal move and are supposed to lose, your opponent doesn’t have enough pieces to checkmate your king.

Hence the game is drawn.

If you are interested to know more about this then you can check out my article: Can You Checkmate With A King And One Knight? (Explained).

The other scenarios of insufficient mating material are:

  • king vs king
  • king + one bishop vs king
  • king + two knights vs king

FIDE Chess Rules Illegal Move

In general, any move that is made violating the FIDE laws of chess is an illegal move. But specifically, there is a description of illegal moves in the FIDE laws of chess, article 3.10.2 and article 7: irregularities.

As per article 3.10.2, any move that doesn’t fulfill the necessary requirements of articles 3.1-3.9 will be called an illegal move.

Now you may wonder what do these article 3.1-3.9 describes?

Actually, these articles are about how to move the pieces, how to capture the pieces, castling, pawn promotion, en passant, and all other basic things.

Here I am going to explain between the lines, all these in brief.

You can’t move a piece to a square that is already occupied by one of your own pieces (pieces of the same color).

While capturing an opponent’s piece you need to remove that piece from the chessboard and place your piece on that square. All these must be done in a single move. (Also using only one hand)

Whenever your opponent’s piece has the possibility of capturing your piece by moving as per its property. Then your piece is said to be in attack.

Remember you can’t make any move that exposes your king into check.

A piece can attack a square even if it can’t move from its place because that would expose its own king into check.

This is also the reason why a pinned piece (a piece is pinned when it can’t move because a more valuable piece behind it will get exposed to attack) can give a check. Read my article: Can A Pinned Piece Give Check? (Explained) to know more.

A bishop moves diagonally, a rook horizontally, a knight jumps over other pieces and moves in L- shape while the queen can move both horizontally and vertically. (The queen is the most powerful piece in chess ad here’s why)

A pawn can move two squares forward but only on its first move, rest it moves one square forward provided the squares are empty. A pawn can’t move backward and while capturing, a pawn moves diagonally. (You can check out my detailed article on pawn moves in chess here.)

There are also two special properties of pawn. One is en passant and another is pawn promotion.

As per the standard rule, whenever your pawn is on the 5th rank while your opponent’s pawn on the adjacent file moves two squares on its first move, then you have the right to capture that pawn by en passant.

I have discussed this in detail in my article: En Passant In Chess: All You Need To Know!

For pawn promotion as per the standard rule whenever a pawn reaches the 8th rank then it is to be promoted to any of the four pieces: queen, knight, rook, or bishop.

The player has the right to promote the pawn to any of those pieces as per their wish. There is no restriction regarding choosing only previously captured pieces.

To know more about pawn promotion you can check out my article: What Happens When A Pawn Reaches The Other Side? (Explained)

A king can move one square in any direction and it also has a special move called castling.

For castling, the king must move two squares and the rook one square just beside the king. But casting can’t be done if either the king or rook has been already moved previously.

Moreover, if there is a chess piece between the king and the rook or if the square through which the king will pass during castling is attacked by the opponent’s piece then also castling can’t be done.

You can read this article written by me to know more about castling.

So up to here, I discussed all the rules mentioned in articles 3.1 to 3.9 that a player must follow and how violating them will be considered illegal in chess. Now let’s discuss the rules mentioned in article 7 about illegal moves.

As per article 7.5.1, after the player, presses his/her clock the illegal move is said to be completed. Whenever an illegal move is completed then the position just before that illegal move must be restored.

If for some reason the previous move is unidentifiable then the game shall continue from the last identifiable position, before the illegal move was made.

While replacing the illegal move and making a legal move, it is necessary for the player to follow all the touch-move rules which are mentioned in articles 4.3-4.7.

So for example, if a player castles but in an illegal way then to restore the previous position and make a legal move the player must move the king.

This is because while castling a player touches the king first and as per the touch move rule once you touch a piece with the intention to move then you are supposed to do that. (Discussed ahead in this article)

As per article 7.5.2, If a player presses the clock after the pawn reaches the end of the board, (on the square of promotion) but does not replace the pawn with a new piece then it is considered to be an illegal move.

Related Read: What Happens When Chess Clock Runs Out?

Now, as per article 7.5.3, If the player makes a move without pressing the clock then it is an illegal move.

Also, read my article: Why Do Chess Players Hit The Clock? (Explained)to know more about chess clocks and standard chess clock rules.

As per article 7.5.4, If two hands are used by the player to make a single move like castling, promotion, or capturing then also it is an illegal move.

Article 7.5.5 describes what happens when a player makes an illegal move and I have already discussed this with you earlier.

As per Appendix B. Blitz section rules, in Blitz games (fast format chess games) when the illegal move occurs for the second time the opponent is given one minute instead of two minutes extra.

So far I discussed what is an illegal move in chess, what happens when you make it, and the standard FIDE chess rules. Now let’s summarize the list of illegal moves that can occur in a game.

List Of Illegal Moves In Chess:

  • Moving the king into check.
  • Moving the chess pieces differently from their property.
  • Castling the king in check, through a check, or into check.
  • Touching the piece but moving a different piece.
  • Using two hands for castling, capturing, or pawn promotion.
  • Making a different move instead of taking the king out of check.
  • Moving the piece with one hand and pressing the clock with another.

These are the most common and main illegal moves you are going to see in a game. Now further I am going to explain each of these illegal moves one by one.

Moving The King Into Check

You can’t make any move that puts your king into check or exposes it in check. In the above FIDE chess rules for illegal moves, I have already discussed this with you.

Moreover, a king can never be captured. This is because the game ends just before that. As soon as a king gets checkmated the game ends.

Also, one king can’t check another king because whenever one king will try to check another king it would approach that king but that would put it in check. So it can’t be done.

This phenomenon is also known as opposing in chess. I highly recommend you to check out my article Can A King Kill A King In Chess? (Explained) in which I have explained all these in more detail.

Moving The Chess Pieces Different From Their Property

This kind of illegal move happens especially between the players who have just started learning chess and are not so well familiar with how each chess piece moves.

So they make the move they are not supposed to make. For example, moving the pawn in the backward direction is illegal because a pawn can only move in a forwarding direction.

I remember when I used to play with my little sister in the early stages of learning chess she would either move a pawn diagonally in the first move or move a rook diagonally.

But after I corrected her she would smile 🙂 Later on, after learning the movement of the chess pieces properly, she rarely do such mistakes.

Here’s a short video by Howcast, which explains illegal moves.

Castling Under Check

Remember you can’t castle in check, through a check, or into check. look at the below image.


Here as you can see if white king castles then it would be an illegal move. This is because first of all, the white king is already checked by the black queen on the square it is standing in.

Secondly, if the king wants to castle then it would have to move through the squares which are already attacked by black rook and black bishop.

So it is illegal for the white king to castle in this situation. You can also check out my article: Castling Under Check: All Doubts Solved! in which I have explained all these in more detail.

Touching One Piece And Moving A Different Piece

Once you touch a piece with the intention to move then you are supposed to move that piece only. This is known as the touch move rule.

If you make a different move from the piece you touched, then that move is considered to be an illegal move.

For the sake of adjusting the pieces, you are supposed to express your intention by saying ‘I adjust” or ‘j’adoube’ before adjusting the pieces.

I have already written an article Why Do Chess Players Touch The Pieces? (Explained) in which I have discussed the touch move rule and all other related things in detail. You can check that out for further reference.

Using Two Hands To Make A Move

You can use only one hand to make a move. It is illegal to use two hands to capture, castle, or promote a pawn.

All these are clearly mentioned in the FIDE laws of chess that I discussed with you earlier. In fact, one of these incidents of illegal moves happened in real tournament chess.

GM Hikaru Nakamura used two hands to castle but his opponent didn’t notice, neither the arbiters present at that time so the game continued and Hikaru won the game. But later on, his opponent claimed regarding this incident and said it was clearly a violation of the rule.

I have discussed this topic in more detail in my article: Can You Castle With Two Hands? Is It Illegal? which you can read if interested.

Making A Different Move Instead Of Taking The King Out Of Check

It is completely illegal to make a different move if your king is already in check. The prime goal of chess is to checkmate the opponent’s king but also with protecting your own king.

If your king is attacked then you are supposed to save your king first. Remember losing the king means losing the game.

Moving The Piece With One Hand And Pressing The Clock With Another

You can’t make a move with one hand and press the clock with another hand. This is against the standard rules and considered an illegal move

Now you may ask why this rule exists as it would save time using two hands. Right? Actually, to avoid the complexities that could arise if it was allowed to use two hands.

For example, it would happen that in a hurry you forgot to make the move but pressed the clock, or you and your opponent both pressed the clock simultaneously.

So it would become a complete mess and many peculiar disputes may arise between the players. So to resolve all these it is standardized that a player must move a piece with one hand and use the same hand o press the clock.

Here’s a video from GM CHESS LESSONS which shows the illegal moves made by top chess players like Magnus Carlsen and Hikaru Nakamura.


So that’s it! Hope you found this article helpful and I was able to solve all your doubts. If interested to read more then you can also check out my articles below.

Thanks! And Good Luck! 🙂