Answers.Body: <p>It is possible for a position to change in such a way that an illegal move becomes legal. As one example, if a move would result in your king being in check, then it is illegal, but if you make one (or more) move(s) so that later the same move would not result in check, then it becomes legal. The following diagram presents one such situation:</p>
  
  <pre><code>[FEN "q1k5/8/8/8/8/8/1Q6/1K6 w - - 0 1"]
  [StartFlipped "0"]
  
  1.Qa2 Kb7 2.Ka1
  </code></pre>
  
  <p>In the beginning position of the above construction, the white king cannot move to a1, since that would be check. However, if white first moved their queen onto a2, then they would be able to move their king to a1 later.</p>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2018-08-20T20:21:36.133Z
Answers.LastActivityDate: 2018-08-21T13:33:43.777Z
Answers.LastEditDate: 2018-08-21T13:33:43.777Z
Answers.UserDisplayName: GreenMatt
Answers.Body: <p>In blitz I believe if you make an illegal move and your opponent doesn't notice it, and then completes their move, the position stands as valid.</p>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2018-08-20T18:24:00.807Z
Answers.LastActivityDate: 2018-08-20T22:57:56.220Z
Answers.LastEditDate: 2018-08-20T22:57:56.220Z
Answers.UserDisplayName: Ywapom
Body: <p>Say I somehow make an illegal move, what happens? If I realize, can I then take it back, and make it legal? If so, how?</p>
  
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2018-08-20T14:25:21.900Z
Comments.Text: Can you precise what you mean by "make an illegal move legal" ? An illegal move is by definition, illegal. But if d2-d4 is illegal at some point because you have a bishop in the way on d3, then removing this bishop would possibly make a later d2-d4 legal. Maybe you mean smg else altogether, but you need to explain yourself.
Comments.UserDisplayName: Evargalo
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2018-08-20T14:53:17.187Z
Comments.Text: Yes, you need to explain. Another option to the one mentioned above: Under some rules, if you make an illegal move  (e.g. leaving your own  king under attack) and the opponent (or arbiter) points it out, you are forced to take back that move and make a legal move. Typically in such situations a time bonus is added to the opponent's clock.
Comments.UserDisplayName: user1583209
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2018-08-20T15:35:22.960Z
Comments.Text: If you make an illegal move, and you notice right away, you are usually allowed to change it into a legal move. However, you need to move the piece that you touched if possible. (There is more to be said about this, but I am not sure this is at all what you want.)
Comments.UserDisplayName: quid
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2018-08-21T14:20:29.737Z
Comments.Text: -quid , yeah that's what i wanted
Comments.UserDisplayName: tah
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2018-12-30T16:19:44.473Z
Comments.Text: What do you mean by *"By anyway?"*?
Comments.UserDisplayName: Peter Mortensen
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2019-01-01T10:57:47.047Z
Comments.Text: Honestly i meant every case imaginable .. but quid answered what i needed !
Comments.UserDisplayName: tah
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2020-02-03T15:22:59.147Z
Comments.Text: This has the same question as here, but I am not sure if the answers are still valid since they are 8 years old: https://chess.stackexchange.com/questions/181/i-made-an-illegal-move-what-happens
Comments.UserDisplayName: PhishMaster
Tags: <illegal-move>
Title: What happens if I realize that I made an illegal move?
ThreadText: # What happens if I realize that I made an illegal move?
  
  (Asked by: username_0 on 2018-08-20)
  
  Say I somehow make an illegal move, what happens? If I realize, can I then take it back, and make it legal? If so, how?
  
  **Tags:** illegal-move
  
  > **Comments:**
  > **username_1**: Can you precise what you mean by "make an illegal move legal" ? An illegal move is by definition, illegal. But if d2-d4 is illegal at some point because you have a bishop in the way on d3, then removing this bishop would possibly make a later d2-d4 legal. Maybe you mean smg else altogether, but you need to explain yourself.  
  > **username_2**: Yes, you need to explain. Another option to the one mentioned above: Under some rules, if you make an illegal move  (e.g. leaving your own  king under attack) and the opponent (or arbiter) points it out, you are forced to take back that move and make a legal move. Typically in such situations a time bonus is added to the opponent's clock.  
  > **username_3**: If you make an illegal move, and you notice right away, you are usually allowed to change it into a legal move. However, you need to move the piece that you touched if possible. (There is more to be said about this, but I am not sure this is at all what you want.)  
  > **username_0**: -username_3 , yeah that's what i wanted  
  > **username_4**: What do you mean by *"By anyway?"*?  
  > **username_0**: Honestly i meant every case imaginable .. but username_3 answered what i needed !  
  > **username_5**: This has the same question as here, but I am not sure if the answers are still valid since they are 8 years old: https://chess.stackexchange.com/questions/181/i-made-an-illegal-move-what-happens  
  
  ---
  
  ## 2 answers
  
  ### Answer by username_6 on 2018-08-20. Score: 4 | Accepted answer
  
  It is possible for a position to change in such a way that an illegal move becomes legal. As one example, if a move would result in your king being in check, then it is illegal, but if you make one (or more) move(s) so that later the same move would not result in check, then it becomes legal. The following diagram presents one such situation:
  
  ```
  [FEN "q1k5/8/8/8/8/8/1Q6/1K6 w - - 0 1"]
  [StartFlipped "0"]
  
  1.Qa2 Kb7 2.Ka1
  
  ```
  
  In the beginning position of the above construction, the white king cannot move to a1, since that would be check. However, if white first moved their queen onto a2, then they would be able to move their king to a1 later.
  
  
  ---
  
  ### Answer by username_7 on 2018-08-20. Score: 3
  
  In blitz I believe if you make an illegal move and your opponent doesn't notice it, and then completes their move, the position stands as valid.
  
  
  ---
  
  