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  1. #1
    CC Grandmaster ER's Avatar
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    Selfmate by illegal move / checkmate in illegal position

    For argument's sake.
    In the position below, White promotes into a wrong colour (black) Queen and presses his (her) clock!

    Attachment 3127

    Has he(she) self mated?
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    Quote Originally Posted by Elliott Renzies View Post
    For argument's sake.
    In the position below, White promotes into a wrong colour (black) Queen and presses his (her) clock!

    Attachment 3127

    Has he(she) self mated?
    No. He/she has made an illegal move.
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  3. #3
    CC Grandmaster ER's Avatar
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    Quote Originally Posted by Andrew Hardegen View Post
    No. He/she has made an illegal move.
    Thanks Andrew Hardegen!
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    Quote Originally Posted by Elliott Renzies View Post
    Thanks Andrew Hardegen!
    You're welcome. It would be interesting to know what should happen if, after the `checkmate' by illegal move, both players write 0-1 on the scoresheets, then sign and submit them.

    I think that the following two articles would come into play:

    Quote Originally Posted by FIDE Laws of Chess
    5.1
    The game is won by the player who has checkmated his opponent’s king. This immediately ends the game, provided that the move producing the checkmate position was in accordance with Article 3 and Articles 4.2 – 4.7.

    8.7
    At the conclusion of the game both players shall sign both scoresheets, indicating the result of the game. Even if incorrect, this result shall stand, unless the arbiter decides otherwise.
    Article 5.1 indicates that the game is not over, since the move to produce the `checkmate' is not a legal one.

    Thus -- assuming no-one has resigned, and the game has not ended in some other way -- both players have signed the scoresheets before the conclusion of the game. Thus the second part of Article 8.7 should not be applied.

    If it were up to me as arbiter, I would -- schedule permitting -- go back to the original position, deal with the illegal move as specified in Article 7.5 or A4.b, and have the players play out the game.
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  5. #5
    Monster of the deep Kevin Bonham's Avatar
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    Andrew is right re Elliott's example. A checkmate resulting from an illegal move is an illegal move and therefore is not checkmate. Also checkmate is defined as placing the opposing king under attack. Placing your own king under attack so that it can't move without being taken, even if it could be done by a legal move, isn't covered.

    For a rapid or blitz game under Elliott's example, what black should do, if solely concerned with a good result, is claim a win by illegal move.

    Here is a trickier case I've never thought of before concerning illegal moves: it is a normal game and black immediately plays a legal move with a piece other than "his" new queen, before the arbiter has seen the illegal move by the opponent. Black now claims a win by checkmate on the grounds that white is checkmated and that his last move was legal. What should the arbiter do, and does it depend on what the move actually was?

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    Quote Originally Posted by Kevin Bonham View Post
    Here is a trickier case I've never thought of before concerning illegal moves: it is a normal game and black immediately plays a legal move with a piece other than "his" new queen, before the arbiter has seen the illegal move by the opponent. Black now claims a win by checkmate on the grounds that white is checkmated and that his last move was legal. What should the arbiter do, and does it depend on what the move actually was?
    Thanks Kevin, this certainly is an interesting case. If I am correct, the issue here is that an illegal move can only be corrected while the game is in progress. If an illegal move is completed, then checkmate is played legally before the illegality of the preceding move is pointed out by either player or observed by the arbiter, the checkmate stands. The losing player has no recourse.

    I think there would be countless rated games in which a player completes an illegal move which leaves their king en prise. In the vast majority of cases, the irregularity is corrected there and then. But in some of these cases, it may be possible for the opponent to checkmate the first player immediately after the illegal move is made, leaving them without any real opportunity to make any claim.

    Perhaps one way to avoid these kinds of situations would be to change Rule 5.1 ...

    Quote Originally Posted by FIDE Laws of Chess
    5.1
    The game is won by the player who has checkmated his opponent’s king. This immediately ends the game, provided that the move producing the checkmate position was in accordance with Article 3 and Articles 4.2 – 4.7.
    ... to the following, or something similar:

    5.1
    The game is won by the player who has checkmated his opponent’s king. This immediately ends the game, provided that the move producing the checkmate position was made from a legal position, and was in accordance with Article 3 and Articles 4.2 – 4.7.
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  7. #7
    Monster of the deep Kevin Bonham's Avatar
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    Quote Originally Posted by Andrew Hardegen View Post
    Thanks Kevin, this certainly is an interesting case. If I am correct, the issue here is that an illegal move can only be corrected while the game is in progress. If an illegal move is completed, then checkmate is played legally before the illegality of the preceding move is pointed out by either player or observed by the arbiter, the checkmate stands. The losing player has no recourse.
    This is what I have always thought. But just yesterday I realise that the "loser" might get technical:

    The objective of each player is to place the opponent’s king ‘under attack’ in such a way that the opponent has no legal move. The player who achieves this goal is said to have ‘checkmated’ the opponent’s king and to have won the game.

    In this example Black did not place white's king under attack. Rather, white placed his own king under attack, and in a way such that White had no legal move, before Black moved. "Place" implies either that the king was not already attacked, or at least that if it was already attacked, Black has caused white to be bereft of legal moves when otherwise White would have been able to move. Neither is the case. Black's move changed nothing.

    The game is won by the player who has checkmated his opponent’s king. This immediately ends the game, provided that the move producing the checkmate position was in accordance with Article 3 and Articles 4.2 – 4.7.

    White might argue that Black did not checkmate him because he was already checkmated and Black made no active contribution to this situation.

    Perhaps it can be argued that Black has still "placed" white in checkmate by making a move that leaves a checkmate position, whereas otherwise Black might have chosen a move that removed it.

    I have not really seen this discussed by arbiters at a high level.

    I think it's generally agreed that if something illegal happens, like a bishop slipping off its diagonal, and later there is a normal checkmate (by a legal move in response to a legal move), then the mate should stand whether the position it was reached in was illegal or not, and that that rule shouldn't be changed. Mainly this is because it is sometimes difficult to determine whether a position is illegal.

    I'm reminded of this from a junior game I saw: 1.e4 d5 2.Bb5+ f5 (illegal) 3.Qh5#.
    Last edited by Kevin Bonham; 24-04-2016 at 06:59 PM.

  8. #8
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    In standard play, we could roll the game back to before the promotion and carry on. I think this is more of a case of being a situation that the rules don't really cover, and the Arbiter making a ruling in the spirit of the rules if called upon to do so.

    Arguably it brings chess into disrepute as well - if you see an illegal move, the move should be rolled back or claimed as a win where applicable, not taken advantage of in this fashion.

    A key difference between this and the junior game of Kevin's is that the finish of the junior game cannot be reached from any legal series of moves, so is not checkmate.
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  9. #9
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    Quote Originally Posted by Kevin Bonham
    This is what I have always thought. But just yesterday I realise that the "loser" might get technical:

    The objective of each player is to place the opponent’s king ‘under attack’ in such a way that the opponent has no legal move. The player who achieves this goal is said to have ‘checkmated’ the opponent’s king and to have won the game.

    In this example Black did not place white's king under attack. Rather, white placed his own king under attack, and in a way such that White had no legal move, before Black moved. "Place" implies either that the king was not already attacked, or at least that if it was already attacked, Black has caused white to be bereft of legal moves when otherwise White would have been able to move. Neither is the case. Black's move changed nothing.
    The more I think about it, the more I agree with this interpretation. The current wording of the Laws seems to prevent the game from being lost by `self-mate', even when the illegal move goes unnoticed.

    In Elliott's example: if Black were to `unmate' White by moving the promoted Queen, the game could proceed as normal.

    Quote Originally Posted by Kevin Bonham
    The game is won by the player who has checkmated his opponent’s king. This immediately ends the game, provided that the move producing the checkmate position was in accordance with Article 3 and Articles 4.2 – 4.7.

    White might argue that Black did not checkmate him because he was already checkmated and Black made no active contribution to this situation.

    Perhaps it can be argued that Black has still "placed" white in checkmate by making a move that leaves a checkmate position, whereas otherwise Black might have chosen a move that removed it.
    I think that most players would hold the latter view. This would certainly simplify things.

    However, if we hold the view that Black cannot make any active contribution to the checkmate (since White is already checkmated), what would happen if Black makes a move that maintains a checkmate position?

    Black claims checkmate; the arbiter says no it isn't. White has no legal moves, so the game cannot continue. It is not stalemate, since White is in check.

    Instead, I think that this meets the definition of a `dead' position, as there is no sequence of legal moves that lead to either player checkmating the other. As such, the game is ended: the arbiter must declare the game drawn under Article 5.2b. The arbiter may note that one or more illegal moves have been played, but he would not be able to do anything to correct these illegal moves once the game has ended.

    Quote Originally Posted by Craig_Hall View Post
    A key difference between this and the junior game of Kevin's is that the finish of the junior game cannot be reached from any legal series of moves, so is not checkmate.
    Is `legal series of moves' really a requirement though? For me, the move 3. Qh5 seems to meet all of the conditions of Article 3 (note that 3.10c is really more a definition of a term than a condition in its own right).

    I agree with Kevin that, should the position become illegal, it may be unfair to rule out the possibility of either player winning. I like the idea of requiring that checkmate must be in response to a legal move. It would produce the right outcomes in these two examples, provided that draws under 5.2b can be prevented.
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  10. #10
    Monster of the deep Kevin Bonham's Avatar
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    Quote Originally Posted by Craig_Hall View Post
    A key difference between this and the junior game of Kevin's is that the finish of the junior game cannot be reached from any legal series of moves, so is not checkmate.
    The Laws don't clearly require that a checkmate position be reachable by a legal series of moves. The move producing checkmate must accord with Article 3 but a move that accords with Article 3 can be made in a position that doesn't.

  11. #11
    Monster of the deep Kevin Bonham's Avatar
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    Quote Originally Posted by Andrew Hardegen View Post
    However, if we hold the view that Black cannot make any active contribution to the checkmate (since White is already checkmated), what would happen if Black makes a move that maintains a checkmate position?

    Black claims checkmate; the arbiter says no it isn't. White has no legal moves, so the game cannot continue. It is not stalemate, since White is in check.
    The arbiter would just wind back to a previous legal position (if possible).

    I disallowed the 3-move example I saw because it was in an event where the focus is on learning and not just competition and FIDE Laws are not strictly applied. But I think most arbiters would accept it as a win in a more formal event, the issue being just that the Laws don't seem to really say it is a win.

  12. #12
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    Quote Originally Posted by Andrew Hardegen View Post
    Is `legal series of moves' really a requirement though? For me, the move 3. Qh5 seems to meet all of the conditions of Article 3 (note that 3.10c is really more a definition of a term than a condition in its own right).
    In my opinion, article 5 requires that the move which ends the game (whether checkmate, stalemate or dead position) complies with Article 3, and 3.10c is sufficiently clear in its definition to be able to draw the conclusion that the move which ends the game must comply with 3.10c. Really, the main reason I'd push this interpretation is that the rule was added for a reason, and this looks like a good example of the rule in practice.
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    Quote Originally Posted by Craig_Hall View Post
    In my opinion, article 5 requires that the move which ends the game (whether checkmate, stalemate or dead position) complies with Article 3, and 3.10c is sufficiently clear in its definition to be able to draw the conclusion that the move which ends the game must comply with 3.10c. Really, the main reason I'd push this interpretation is that the rule was added for a reason, and this looks like a good example of the rule in practice.
    Quote Originally Posted by FIDE Laws of Chess
    3.10
    c. A position is illegal when it cannot have been reached by any series of legal moves.
    3.10c is clear in its definition of `illegal position', but it is a definition and not a rule. It serves its purpose as a definition. It does not follow that a legal move, including checkmate, cannot be made in an illegal position. Kevin has addressed this in #10.
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  14. #14
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    Quote Originally Posted by Kevin Bonham View Post
    The arbiter would just wind back to a previous legal position (if possible).
    If I were the arbiter, then I would be in favour of winding back to a previous legal position. It just seems like the right thing to do. But after Black's (legal) move which maintains the `checkmate', doesn't the resulting position meet the criterion of 5.2b, while not satisfying 5.1 or 5.2a? Hasn't the game already ended?
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  15. #15
    Monster of the deep Kevin Bonham's Avatar
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    Quote Originally Posted by Andrew Hardegen View Post
    If I were the arbiter, then I would be in favour of winding back to a previous legal position. It just seems like the right thing to do. But after Black's (legal) move which maintains the `checkmate', doesn't the resulting position meet the criterion of 5.2b, while not satisfying 5.1 or 5.2a? Hasn't the game already ended?
    Ah, I see what you mean about 5.2 now. The arbiter could safely declare an exception in this case on the grounds that 5.2b wasn't meant to apply to situations like this and was designed for positions that are "dead drawn", rather than for apparent mates that someone might claim aren't really mate.

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