Answers.Body: <p>You noticed immediately, which makes it very easy because in this case the rules are the same (apart from time penalty) for all forms of chess. In the first instance you have to take back the illegal move and make a legal move. If possible you have to move the piece you touched. So, if your king could legally move to another square that's the move you would have to make. If it could legally move to several squares then you could choose between them.</p>
  
  <p>For a first offence your opponent gains time on the clock. At blitz this is 1 minute and for standard and rapid it is 2 minutes. A second offence loses the game. But note that these penalties only apply if you pressed the clock before your opponent noticed and told you. If you did not press the clock then there is no penalty. You just have to make a legal move with the piece you touched.</p>
  
  <p>The rules governing this are the <a href="https://handbook.fide.com/chapter/E012018" rel="nofollow noreferrer">FIDE Laws of Chess</a>. This is what they have to say:</p>
  
  <blockquote>
    <p>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.</p>
    
    <p>7.5.5   After the action taken under Article 7.5.1, 7.5.2, 7.5.3 or 7.5.4 for the first completed illegal move by a player, the arbiter shall give two minutes extra time to his opponent; for the second
    completed 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.</p>
  </blockquote>
  
  <p>Those are the rules for standard time control where the moves are being written. Because the moves are being written down it doesn't matter if the illegal move is noticed after several more moves were played, you still have to go back to the position when the illegal move was made and make a legal move instead.</p>
  
  <p>For rapid and blitz this usually isn't possible and so the rules say that the illegal move has to be flagged before the next move. Appendix A in the Laws deals with rapid and the rule says:</p>
  
  <blockquote>
    <p>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.</p>
  </blockquote>
  
  <p>Appendix B deals with blitz and that says:</p>
  
  <blockquote>
    <p>B.4 Otherwise, play shall be governed by the Rapid chess Laws as in
    Article A.2 and A.4.</p>
  </blockquote>
  
  <p>So, the rules are the same as for rapid, but for the penalties:</p>
  
  <blockquote>
    <p>B.2 The penalties mentioned in Articles 7 and 9 of the Competition
    Rules shall be one minute instead of two minutes.</p>
  </blockquote>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2020-05-27T11:46:09.730Z
Answers.LastActivityDate: 2020-05-27T11:46:09.730Z
Answers.UserDisplayName: Brian Towers
Answers.Body: <p>In this case you would just go back to the last turn. In official tournaments, a rule used is you get a penalty on the first time you make an illegal move, and then if you make 1-2 more illegal moves (for FIDE it's 1 more) you lose the game. But assuming this game was just for fun, as it seems no arbiter was involved to help out, just take the move back and continue the game.</p>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2020-05-27T04:51:56.907Z
Answers.LastActivityDate: 2020-05-27T18:34:29.667Z
Answers.LastEditDate: 2020-05-27T18:34:29.667Z
Answers.UserDisplayName: Inertial Ignorance
Answers.Body: <p>It depends on the tournament policy that you play. For some tournaments, there is a penalty such as losing the game if you have done 3 illegal moves. The procedure is generally like this: Your opponent should stop the clock and call the referee. The rest depends on the decision of the referee.</p>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2020-05-27T13:53:33.857Z
Answers.Text: What you have written is factually incorrect
Answers.UserDisplayName: Brian Towers
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2020-05-27T13:56:00.017Z
Answers.Text: No, it is correct in Turkey.
Answers.UserDisplayName: FuzzyFiso
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2020-05-27T10:29:47.737Z
Answers.LastActivityDate: 2020-05-27T10:29:47.737Z
Answers.UserDisplayName: FuzzyFiso
Body: <p>I moved my king as I wanted it to be in a safer location and after I did my turn my opponent realised that I put my king in check by accident and as the rules state you cannot put your king in check we did not know whether we should go back to my last turn or if my opponent had won the game.</p>
  
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2020-05-26T21:34:26.850Z
Comments.Text: Was it the Blitz or "slow" game? Were the chess clocks used?
Comments.UserDisplayName: Anton Menshov
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2020-05-27T04:20:13.700Z
Comments.Text: There was a time when I thought the term "discovered check" referred to such a situation, when the players suddenly realized that one of the kings had been in check for a while.
Comments.UserDisplayName: bof
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2020-06-03T06:16:42.030Z
Comments.Text: Just pray the other person didn't see that and doesn't call foul play.
Comments.UserDisplayName: Mehroz Mustafa
Tags: <rules><check><kings>
Title: What do you do when you put your king in check and you don’t realise?
ThreadText: # What do you do when you put your king in check and you don’t realise?
  
  (Asked by: username_0 on 2020-05-26)
  
  I moved my king as I wanted it to be in a safer location and after I did my turn my opponent realised that I put my king in check by accident and as the rules state you cannot put your king in check we did not know whether we should go back to my last turn or if my opponent had won the game.
  
  **Tags:** rules, check, kings
  
  > **Comments:**
  > **username_1**: Was it the Blitz or "slow" game? Were the chess clocks used?  
  > **username_2**: There was a time when I thought the term "discovered check" referred to such a situation, when the players suddenly realized that one of the kings had been in check for a while.  
  > **username_3**: Just pray the other person didn't see that and doesn't call foul play.  
  
  ---
  
  ## 3 answers
  
  ### Answer by username_4 on 2020-05-27. Score: 3
  
  You noticed immediately, which makes it very easy because in this case the rules are the same (apart from time penalty) for all forms of chess. In the first instance you have to take back the illegal move and make a legal move. If possible you have to move the piece you touched. So, if your king could legally move to another square that's the move you would have to make. If it could legally move to several squares then you could choose between them.
  
  For a first offence your opponent gains time on the clock. At blitz this is 1 minute and for standard and rapid it is 2 minutes. A second offence loses the game. But note that these penalties only apply if you pressed the clock before your opponent noticed and told you. If you did not press the clock then there is no penalty. You just have to make a legal move with the piece you touched.
  
  The rules governing this are the [FIDE Laws of Chess](https://handbook.fide.com/chapter/E012018). This is what they have to say:
  
  > 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.
  >
  > 7.5.5 After the action taken under Article 7.5.1, 7.5.2, 7.5.3 or 7.5.4 for the first completed illegal move by a player, the arbiter shall give two minutes extra time to his opponent; for the second
  > completed 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.
  
  Those are the rules for standard time control where the moves are being written. Because the moves are being written down it doesn't matter if the illegal move is noticed after several more moves were played, you still have to go back to the position when the illegal move was made and make a legal move instead.
  
  For rapid and blitz this usually isn't possible and so the rules say that the illegal move has to be flagged before the next move. Appendix A in the Laws deals with rapid and the rule says:
  
  > 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.
  
  Appendix B deals with blitz and that says:
  
  > B.4 Otherwise, play shall be governed by the Rapid chess Laws as in
  > Article A.2 and A.4.
  
  So, the rules are the same as for rapid, but for the penalties:
  
  > B.2 The penalties mentioned in Articles 7 and 9 of the Competition
  > Rules shall be one minute instead of two minutes.
  
  
  ---
  
  ### Answer by username_5 on 2020-05-27. Score: 2
  
  In this case you would just go back to the last turn. In official tournaments, a rule used is you get a penalty on the first time you make an illegal move, and then if you make 1-2 more illegal moves (for FIDE it's 1 more) you lose the game. But assuming this game was just for fun, as it seems no arbiter was involved to help out, just take the move back and continue the game.
  
  
  ---
  
  ### Answer by username_6 on 2020-05-27. Score: 0
  
  It depends on the tournament policy that you play. For some tournaments, there is a penalty such as losing the game if you have done 3 illegal moves. The procedure is generally like this: Your opponent should stop the clock and call the referee. The rest depends on the decision of the referee.
  
  > **Comments:**
  > **username_4**: What you have written is factually incorrect  
  > **username_6**: No, it is correct in Turkey.  
  
  ---
  
  