Answers.Body: <blockquote>
    <p>A player who makes an illegal move must retract that move and make a
    legal move. That move must be made with the same piece if possible,
    because the touch-move rule applies. If the illegal move was an
    attempt to castle, the touch-move rule applies to the king but not to
    the rook. The arbiter should adjust the time on the clock according to
    the best evidence. If the mistake is only noticed later on, the game
    should be restarted from the position in which the error occurred
    (Schiller 2003:24–25). Some regional organizations have different
    rules.</p>
    
    <p>If blitz chess is being played (in which both players have a small,
    limited time, e.g. five minutes) the rule varies. A player may correct
    an illegal move if the player has not pressed their clock. If a player
    has pressed their clock, the opponent may claim a win if he or she
    hasn't moved. If the opponent moves, the illegal move is accepted and
    without penalty (Schiller 2003:77).</p>
  </blockquote>
  
  <p><strong>SOURCE:</strong> <a href="http://en.wikipedia.org/wiki/Rules_of_chess#Illegal_move">Rules of Chess, Illegal move</a></p>
  
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2012-05-03T13:30:21.890Z
Answers.LastActivityDate: 2012-05-03T13:30:21.890Z
Answers.UserDisplayName: blunders
Answers.Body: <p>This only really applies to over the board games (since online chess servers prevent illegal moves).</p>
  <p>In a <strong>standard time control game, under USCF rules</strong>, when the illegal move is noticed by one of the players, a few things happen.  First, the illegal move must have been made within the last 10 moves.  If not, then the current position stands, and play continues.  Assuming that the move is recent, the position is restored to the position immediately before the illegal move.</p>
  <p>Then, the player that made the illegal move now must make a legal move with the same piece (if one exists).  If there are no legal moves, then the player is free to make any move.  This is due to the <a href="http://en.wikipedia.org/wiki/Touch-move_rule" rel="noreferrer">touch move rule</a>.  Finally, if the offending player has pressed the clock, a two minute &quot;bonus&quot; is added to the opponent's clock to compensate them for any time lost and to penalize the offending player.</p>
  <p>Here is the relevant passage from the USCF rulebook:</p>
  <blockquote>
  <p><strong>11A. Illegal move during last ten moves.</strong> If, during a game, it is found that one of either player's last ten moves was illegal, the position shall be reinstated to what it was before the illegal move. The game shall then continue by applying Rule 10, The Touched Piece, to the move replacing the illegal move. If the position cannot be reinstated, then the illegal move shall stand. Move counters on clocks that have them may by readjusted.</p>
  <p><strong>11D. Illegal move.</strong> If, a player completes an illegal move by pressing the clock, in addition to the usual obligation to make a legal move with the touched piece if possible, the standard penalty specified in rule 1C2a applies (i.e. two minutes added to the opponent's clock).</p>
  </blockquote>
  <p>In <strong>blitz chess</strong>, the rules are different.  According to the <a href="http://en.wikipedia.org/wiki/Fast_chess" rel="noreferrer">WBCA</a> (World Blitz Chess Association) rules, a player who makes an illegal move loses the game instantly.  This rule is frequently enforced in casual games too.  The most common way that this occurs is that one player doesn't notice that they are in check and makes a move that doesn't get out of check.  Then the checking player simply captures the king and claims a victory.</p>
  <p>Because blitz is a much faster pace game, the illegal move must be noticed within two moves.  If it is not, then the current position stands and play continues.</p>
  <p>At no point is the game cancelled due to an illegal move.  Pretty much once a game starts and both players make a move, a result of win, loss, or draw will be recorded.</p>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2021-11-20T13:35:24.493Z
Answers.Text: In tournaments in the UK a few years ago, if you made an illegal move and your opponent pointed it out, your opponent can claim a win. But maybe these rules have changed now? Or maybe it's just certain tournaments in the UK?
Answers.UserDisplayName: Adam Rubinson
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2022-07-27T16:42:52.350Z
Answers.Text: "At no point is the game cancelled due to an illegal move. Pretty much once a game starts and both players make a move, a result of win, loss or draw will be recorded."
  
  Just to be clear, FIDE Rule 7.1.a (2012), Incorrect Starting Position, results in a new game, regardless of the state of the current game.
Answers.UserDisplayName: jaxter
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2013-07-08T12:39:22.200Z
Answers.Text: Note that these are the *USCF* rules, used in the US. The FIDE rules used everywhere else are slightly different.
Answers.UserDisplayName: RemcoGerlich
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2013-07-08T13:52:36.967Z
Answers.Text: @RemcoGerlich agreed, the differences mainly apply to adjusting the clocks.  The answer by blunders quotes the FIDE rules.
Answers.UserDisplayName: Andrew
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Answers.CreationDate: 2013-07-08T17:15:57.700Z
Answers.Text: Under FIDE rules, there is no 10 move limit after which an illegal move stands. And if the position before the illegal move can't be reconstructed, USCF continues with the current position, but FIDE continues with the last known position before the illegal move -- which may be the starting position. Capturing the king in blitz counts as an illegal move itself under FIDE rules, and the opponent can claim a win if you try to claim a win using that. There's also a distinction between classical and rapid chess, in rapid the players must claim but in classical the arbiter can act on his own.
Answers.UserDisplayName: RemcoGerlich
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Answers.LastEditDate: 2020-06-17T09:59:59.497Z
Answers.UserDisplayName: Andrew
Body: <p>Especially in blitz or bullet games, it is possible that a player makes an illegal move, for example castles through check. </p>
  
  <ul>
  <li><p>If the opponent does notice the illegal move, then as far as I know the first player is obliged to make a legal move with the same piece, if one exists. What if there are no legal moves? </p></li>
  <li><p>What if the opponent, being in time pressure, doesn't notice the illegal move and makes a move. What happens after they realize that? Does the person who made the illegal move forfeit? Or is the whole game cancelled?</p></li>
  </ul>
  
  <p>Are there any standard rules for these kinds of situations?</p>
  
Tags: <rules><illegal-move>
Title: I made an illegal move. What happens?
ThreadText: # I made an illegal move. What happens?
  
  (Asked by: username_0 on 2012-05-03)
  
  Especially in blitz or bullet games, it is possible that a player makes an illegal move, for example castles through check.
  
  * If the opponent does notice the illegal move, then as far as I know the first player is obliged to make a legal move with the same piece, if one exists. What if there are no legal moves?
  * What if the opponent, being in time pressure, doesn't notice the illegal move and makes a move. What happens after they realize that? Does the person who made the illegal move forfeit? Or is the whole game cancelled?
  
  Are there any standard rules for these kinds of situations?
  
  **Tags:** rules, illegal-move
  
  
  ---
  
  ## 2 answers
  
  ### Answer by username_2 on 2012-05-03. Score: 40 | Accepted answer
  
  This only really applies to over the board games (since online chess servers prevent illegal moves).
  
  In a **standard time control game, under USCF rules**, when the illegal move is noticed by one of the players, a few things happen. First, the illegal move must have been made within the last 10 moves. If not, then the current position stands, and play continues. Assuming that the move is recent, the position is restored to the position immediately before the illegal move.
  
  Then, the player that made the illegal move now must make a legal move with the same piece (if one exists). If there are no legal moves, then the player is free to make any move. This is due to the [touch move rule](http://en.wikipedia.org/wiki/Touch-move_rule). Finally, if the offending player has pressed the clock, a two minute "bonus" is added to the opponent's clock to compensate them for any time lost and to penalize the offending player.
  
  Here is the relevant passage from the USCF rulebook:
  
  > **11A. Illegal move during last ten moves.** If, during a game, it is found that one of either player's last ten moves was illegal, the position shall be reinstated to what it was before the illegal move. The game shall then continue by applying Rule 10, The Touched Piece, to the move replacing the illegal move. If the position cannot be reinstated, then the illegal move shall stand. Move counters on clocks that have them may by readjusted.
  >
  > **11D. Illegal move.** If, a player completes an illegal move by pressing the clock, in addition to the usual obligation to make a legal move with the touched piece if possible, the standard penalty specified in rule 1C2a applies (i.e. two minutes added to the opponent's clock).
  
  In **blitz chess**, the rules are different. According to the [WBCA](http://en.wikipedia.org/wiki/Fast_chess) (World Blitz Chess Association) rules, a player who makes an illegal move loses the game instantly. This rule is frequently enforced in casual games too. The most common way that this occurs is that one player doesn't notice that they are in check and makes a move that doesn't get out of check. Then the checking player simply captures the king and claims a victory.
  
  Because blitz is a much faster pace game, the illegal move must be noticed within two moves. If it is not, then the current position stands and play continues.
  
  At no point is the game cancelled due to an illegal move. Pretty much once a game starts and both players make a move, a result of win, loss, or draw will be recorded.
  
  > **Comments:**
  > **username_5**: Note that these are the *USCF* rules, used in the US. The FIDE rules used everywhere else are slightly different.  
  > **username_2**: @username_5 agreed, the differences mainly apply to adjusting the clocks.  The answer by username_1 quotes the FIDE rules.  
  > **username_5**: Under FIDE rules, there is no 10 move limit after which an illegal move stands. And if the position before the illegal move can't be reconstructed, USCF continues with the current position, but FIDE continues with the last known position before the illegal move -- which may be the starting position. Capturing the king in blitz counts as an illegal move itself under FIDE rules, and the opponent can claim a win if you try to claim a win using that. There's also a distinction between classical and rapid chess, in rapid the players must claim but in classical the arbiter can act on his own.  
  > **username_3**: In tournaments in the UK a few years ago, if you made an illegal move and your opponent pointed it out, your opponent can claim a win. But maybe these rules have changed now? Or maybe it's just certain tournaments in the UK?  
  > **username_4**: "At no point is the game cancelled due to an illegal move. Pretty much once a game starts and both players make a move, a result of win, loss or draw will be recorded."  Just to be clear, FIDE Rule 7.1.a (2012), Incorrect Starting Position, results in a new game, regardless of the state of the current game.  
  
  ---
  
  ### Answer by username_1 on 2012-05-03. Score: 13
  
  > A player who makes an illegal move must retract that move and make a
  > legal move. That move must be made with the same piece if possible,
  > because the touch-move rule applies. If the illegal move was an
  > attempt to castle, the touch-move rule applies to the king but not to
  > the rook. The arbiter should adjust the time on the clock according to
  > the best evidence. If the mistake is only noticed later on, the game
  > should be restarted from the position in which the error occurred
  > (Schiller 2003:24–25). Some regional organizations have different
  > rules.
  >
  > If blitz chess is being played (in which both players have a small,
  > limited time, e.g. five minutes) the rule varies. A player may correct
  > an illegal move if the player has not pressed their clock. If a player
  > has pressed their clock, the opponent may claim a win if he or she
  > hasn't moved. If the opponent moves, the illegal move is accepted and
  > without penalty (Schiller 2003:77).
  
  **SOURCE:** [Rules of Chess, Illegal move](http://en.wikipedia.org/wiki/Rules_of_chess#Illegal_move)
  
  
  ---
  
  