Answers.Body: <p>From the FIDE Laws of Chess, article 7.6:</p>
  
  <blockquote>
    <p>If, during a game, it is found that any piece has been displaced from its correct square the position 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. The game shall then continue from this reinstated position. </p>
  </blockquote>
  
  <p>Put into practice:</p>
  
  <ul>
  <li>If the moves are logged, then it's trivial to determine the "last identifiable position" and the game can be resumed as if nothing happened.</li>
  <li>If they are not logged (or the two scoresheets differ), the arbiter can attempt to find the "last identifiable position" by asking both players. If they both remember the exact same position, then the game can continue from that position.</li>
  <li>If that fails too (because the players don't remember or disagree), there is at least one "last identifiable position" that can always be determined,  the starting position. So yeah, the game is essentially reset in that case. </li>
  </ul>
  
  <p>Article 7.1 applies basically the same rule to the readjustment of the clock, if there is one (with some more wiggle room for the arbiter):</p>
  
  <blockquote>
    <p>If an irregularity occurs and the pieces have to be restored to a previous position, the arbiter shall use his best judgement to determine the times to be shown on the chessclock. This includes the right not to change the clock times. He shall also, if necessary, adjust the clock’s move-counter. </p>
  </blockquote>
  
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2017-12-18T15:21:49.290Z
Answers.Text: _'If the moves are logged, then it's trivial to determine the "last identifiable position" and the game can be resumed as if nothing happened.'_ It's not that trivial. If at some point you realize that a knight that should be on c3 is now on d3, how do you when that happened? By this rule (because the wrong position might have affected the players' thinking), you should return to the position before the error occurred, but the scoresheet doesn't tell anything about it.
Answers.UserDisplayName: JiK
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Answers.Text: @JiK:. The score sheet tells you how to replay the game from scratch, so you don't have to find the irregularity.  You just throw the current position out entirely.
Answers.UserDisplayName: Kevin
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Answers.CreationDate: 2017-12-18T16:29:12.267Z
Answers.Text: @Kevin: Suppose move 23 was Nh3, move 29 was ...Qf4, and White's 35th move would have been to move the knight from g3 to e2 except that Black realized the knight couldn't have been on g3 and called the arbiter.  Suppose further that all moves from 24 to 34 would have been equally legal with the knight on g3 or h3.  Should White be allowed to take the queen on f4?  If the knight had been on h3 when Black played ...Qf4 that would be fair, but if the knight had been sitting on g3 it would be unfair to suggest that Black should have noticed that it was "really" on h3 and was thus controlling f4.
Answers.UserDisplayName: supercat
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Answers.CreationDate: 2017-12-18T16:36:58.077Z
Answers.Text: @Kevin: If an arbiter had a video of the game, it would make sense to reset the board and clocks to the point where the board position first diverged from the official one, but otherwise it would be necessary for the arbiter to guess.  Most likely, the fact that White hadn't taken Black's queen on move 30 would be taken as a sign that the knight hadn't been on h3 at that time (and must have been displaced prior to that) but either player's moves could have been arbitrarily influenced by the misplaced knight any time after move 23.
Answers.UserDisplayName: supercat
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Answers.Text: @Kevin That's not the rule. The rule explicity says that you should return to the position where the irregularity occurred and forget all moves that have been made after that.
Answers.UserDisplayName: JiK
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Answers.CreationDate: 2017-12-18T20:31:28.577Z
Answers.Text: Guys, this is about the whole board getting wrecked, not an irregular move by a player. The knight is neither on c3, d3, g3 or h3. It lies somewhere on the floor. The game is replayed based on the scoresheets of both players and if they happen to diverge at move 23, then that's the position where the game gets resumed. End of story.
Answers.UserDisplayName: Annatar
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2017-12-18T21:40:05.307Z
Answers.Text: @Annatar The question is about *the board getting distrubed*, the earthquake is only an example but doesn't limit the question of cases where the whole board is wrecked.
Answers.UserDisplayName: JiK
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Answers.CreationDate: 2017-12-19T07:09:57.233Z
Answers.Text: @JiK It is about the board getting disturbed *by an outside force* ("Clearly no-one has interfered"), not by an irregular move (I think I repeat myself..). If, by chance, such a move actually has happened, it only matters insofar the "last identifiable position" is the one before that move, instead of the one before the earthquake or whatever. But there *is* one.
Answers.UserDisplayName: Annatar
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Answers.Text: @Annatar Nobody is talking about an irregular move, just a piece getting displaced by an outside force.
Answers.UserDisplayName: JiK
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Answers.CreationDate: 2017-12-19T16:42:05.240Z
Answers.Text: If you have the scoresheet you can unambiguously determine the position on the board, you can just replay the game from the beginning and it will be correct
Answers.UserDisplayName: reggaeguitar
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Answers.CreationDate: 2017-12-19T21:19:42.690Z
Answers.Text: @reggaeguitar Once again, the rule says that moves that have been made and written into the scoresheet after someone/something displaces a piece have to be discarded.
Answers.UserDisplayName: JiK
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Answers.CreationDate: 2017-12-21T01:57:14.240Z
Answers.Text: I'm saying that if an earthquake happened and knocked all the pieces off the board you could reconstruct the position by replaying the game from the start from the scoresheet(s).
Answers.UserDisplayName: reggaeguitar
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2017-12-22T13:50:07.823Z
Answers.Text: @reggaeguitar That's what everyone is saying, but we are talking about the case when an earthquake moves a piece from one square to another and it's not noticed until a few moves later.
Answers.UserDisplayName: JiK
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Answers.LastEditDate: 2017-12-19T06:58:29.467Z
Answers.UserDisplayName: Annatar
Body: <p>Let's say I'm playing a game that has technically begun (white has moved) and then the board is disturbed: say a minor earthquake shakes the pieces off the table or something.  Clearly no-one has interfered so there is no cheating, but what happens next?</p>
  
  <p>If the moves are logged, can the pieces be returned to their previous positions and the match resumed?  Or must the match be aborted and the board reset?</p>
  
  <p>I'm mostly interested in the international tournament rules but I'm interesting in hearing of 'house rules' as well.</p>
  
Tags: <rules><chessboards>
Title: If a chess board is disturbed, can the game continue?
ThreadText: # If a chess board is disturbed, can the game continue?
  
  (Asked by: username_0 on 2017-12-18)
  
  Let's say I'm playing a game that has technically begun (white has moved) and then the board is disturbed: say a minor earthquake shakes the pieces off the table or something. Clearly no-one has interfered so there is no cheating, but what happens next?
  
  If the moves are logged, can the pieces be returned to their previous positions and the match resumed? Or must the match be aborted and the board reset?
  
  I'm mostly interested in the international tournament rules but I'm interesting in hearing of 'house rules' as well.
  
  **Tags:** rules, chessboards
  
  
  ---
  
  ## 1 answers
  
  ### Answer by username_1 on 2017-12-18. Score: 26 | Accepted answer
  
  From the FIDE Laws of Chess, article 7.6:
  
  > If, during a game, it is found that any piece has been displaced from its correct square the position 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. The game shall then continue from this reinstated position.
  
  Put into practice:
  
  * If the moves are logged, then it's trivial to determine the "last identifiable position" and the game can be resumed as if nothing happened.
  * If they are not logged (or the two scoresheets differ), the arbiter can attempt to find the "last identifiable position" by asking both players. If they both remember the exact same position, then the game can continue from that position.
  * If that fails too (because the players don't remember or disagree), there is at least one "last identifiable position" that can always be determined, the starting position. So yeah, the game is essentially reset in that case.
  
  Article 7.1 applies basically the same rule to the readjustment of the clock, if there is one (with some more wiggle room for the arbiter):
  
  > If an irregularity occurs and the pieces have to be restored to a previous position, the arbiter shall use his best judgement to determine the times to be shown on the chessclock. This includes the right not to change the clock times. He shall also, if necessary, adjust the clock’s move-counter.
  
  > **Comments:**
  > **username_2**: _'If the moves are logged, then it's trivial to determine the "last identifiable position" and the game can be resumed as if nothing happened.'_ It's not that trivial. If at some point you realize that a knight that should be on c3 is now on d3, how do you when that happened? By this rule (because the wrong position might have affected the players' thinking), you should return to the position before the error occurred, but the scoresheet doesn't tell anything about it.  
  > **username_3**: @username_2:. The score sheet tells you how to replay the game from scratch, so you don't have to find the irregularity.  You just throw the current position out entirely.  
  > **username_4**: @username_3: Suppose move 23 was Nh3, move 29 was ...Qf4, and White's 35th move would have been to move the knight from g3 to e2 except that Black realized the knight couldn't have been on g3 and called the arbiter.  Suppose further that all moves from 24 to 34 would have been equally legal with the knight on g3 or h3.  Should White be allowed to take the queen on f4?  If the knight had been on h3 when Black played ...Qf4 that would be fair, but if the knight had been sitting on g3 it would be unfair to suggest that Black should have noticed that it was "really" on h3 and was thus controlling f4.  
  > **username_4**: @username_3: If an arbiter had a video of the game, it would make sense to reset the board and clocks to the point where the board position first diverged from the official one, but otherwise it would be necessary for the arbiter to guess.  Most likely, the fact that White hadn't taken Black's queen on move 30 would be taken as a sign that the knight hadn't been on h3 at that time (and must have been displaced prior to that) but either player's moves could have been arbitrarily influenced by the misplaced knight any time after move 23.  
  > **username_2**: @username_3 That's not the rule. The rule explicity says that you should return to the position where the irregularity occurred and forget all moves that have been made after that.  
  > **username_1**: Guys, this is about the whole board getting wrecked, not an irregular move by a player. The knight is neither on c3, d3, g3 or h3. It lies somewhere on the floor. The game is replayed based on the scoresheets of both players and if they happen to diverge at move 23, then that's the position where the game gets resumed. End of story.  
  > **username_2**: @username_1 The question is about *the board getting distrubed*, the earthquake is only an example but doesn't limit the question of cases where the whole board is wrecked.  
  > **username_1**: @username_2 It is about the board getting disturbed *by an outside force* ("Clearly no-one has interfered"), not by an irregular move (I think I repeat myself..). If, by chance, such a move actually has happened, it only matters insofar the "last identifiable position" is the one before that move, instead of the one before the earthquake or whatever. But there *is* one.  
  > **username_2**: @username_1 Nobody is talking about an irregular move, just a piece getting displaced by an outside force.  
  > **username_5**: If you have the scoresheet you can unambiguously determine the position on the board, you can just replay the game from the beginning and it will be correct  
  > **username_2**: @username_5 Once again, the rule says that moves that have been made and written into the scoresheet after someone/something displaces a piece have to be discarded.  
  > **username_5**: I'm saying that if an earthquake happened and knocked all the pieces off the board you could reconstruct the position by replaying the game from the start from the scoresheet(s).  
  > **username_2**: @username_5 That's what everyone is saying, but we are talking about the case when an earthquake moves a piece from one square to another and it's not noticed until a few moves later.  
  
  ---
  
  