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Last 6 single moves?

Standard memberSwissGambit
Only Chess 22 Sep '12 05:49
  1. S
    Standard memberSwissGambit
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    22 Sep '12 05:491 edit
    N.Petrovic
  2. Ro
    Standard memberRank outsider
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    22 Sep '12 16:31
    Sorry, can I just check one thing, as I am not sure of the conventions in puzzles like this.

    Is the aim to find a starting position from where, six ply later, we end up in the position shown, and where all Black's moves are forced.

    Secondly, how do I do a hidey thingy, in the hugely unlikely event that I have an idea how to solve this?
  3. S
    Standard memberSwissGambit
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    22 Sep '12 21:441 edit
    Originally posted by Rank outsider
    Sorry, can I just check one thing, as I am not sure of the conventions in puzzles like this.

    Is the aim to find a starting position from where, six ply later, we end up in the position shown, and where all Black's moves are forced.

    Secondly, how do I do a hidey thingy, in the hugely unlikely event that I have an idea how to solve this?
    Yeah, that's the aim. The composer has seen to it that there is only one such starting position.

    You can do the hidey thing with [ hidden ] [ /hidden ] tags.

    Reveal Hidden Content
    See?
  4. p
    Standard memberpaulbuchmanfromfics
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    22 Sep '12 22:00
    Originally posted by SwissGambit
    Yeah, that's the aim. The composer has seen to it that there is only one such starting position.

    You can do the hidey thing with [ hidden ] [ /hidden ] tags.

    [hidden]See?[/hidden]
    What other commands can you do?

    bold ?
    italics?

    The Reveal Hidden Content
    hidden!
    thing is cool, but I am always wondering about the other [ ] commands.
  5. S
    Standard memberSwissGambit
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    22 Sep '12 22:01
    Originally posted by paulbuchmanfromfics
    What other commands can you do?

    bold ?
    italics?

    The [hidden]hidden![/hidden] thing is cool, but I am always wondering about the other [ ] commands.
    FAQ
  6. FL
    Standard memberFat Lady
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    22 Sep '12 22:16
    Let's do this one move at a time!

    It's obviously Black's move, because he is in check.

    White's bishop is giving check. It can't have just moved to a1 as otherwise Black would have been in check. So White's last move must have been uncovering the check from the bishop.

    The piece which moved to give discovered check can't have been one of the queens, because they give check along diagonals as well or the bishop on h7, because that's a white-squared bishop, or the king, because that's too far away from the a1-e5 diagonal. So if must have been the pawn. So White's last move was moving that pawn.

    The pawn can't have come from e5, because Black would have been in check, so it must have taken something on e6 (i.e. it started on d5 or f5).

    The thing that the pawn took must have been a pawn on e5 (en passant), otherwise Black would have been in check from the a1 bishop.

    So White's last move was either d5xe6 e.p. or f5xe6 e.p. Let's leave which one it was as undecided for now.

    Black's move before was clearly e7-e5.

    White's move before that must also have been a discovered check for the same reason as his last move was. The only thing which could have moved to give discovered check is a pawn on d4. So that clears up whether it was d5xe6 or f5xe6.

    So, the last few moves were:

    Invert BoardPGNHeadersComments
  7. FL
    Standard memberFat Lady
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    22 Sep '12 22:34
    Now, Black's move before this must have been a king move, because his pawn hasn't moved and we know White doesn't capture any Black pieces subsequently apart from the pawn.

    If the king came from e5, f5, g5 or g6, it would have been in check from two pieces. Double checks are possible, but not in this position. For example, with Black's king on e5, White can't have played e3xd4 because his queen is on e3.

    It looks like this is true if it came from e6 as well, but there is one possibility - if Black was recapturing a white pawn which had itself just captured his f-pawn which had blocked a check!

    So, the solution for the last six moves (I had to add a dummy first move for White) is:

    Invert BoardPGNHeadersComments
  8. S
    Standard memberSwissGambit
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    23 Sep '12 01:30
    Originally posted by Fat Lady
    Now, Black's move before this must have been a king move, because his pawn hasn't moved and we know White doesn't capture any Black pieces subsequently apart from the pawn.

    If the king came from e5, f5, g5 or g6, it would have been in check from two pieces. Double checks are possible, but not in this position. For example, with Black's king on e5, White ...[text shortened]... .
    white to play
    --------------}
    1. Qg4+ f5 2. exf6+ Kxf6 3. d5+ e5 4. dxe6+
    [/pgn]
    SOLV'D
  9. p
    Standard memberpaulbuchmanfromfics
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    23 Sep '12 02:17
    Originally posted by SwissGambit
    FAQ
    Thank you , User 355642 Reveal Hidden Content
    for the help
    here in Thread 148631!
  10. Ro
    Standard memberRank outsider
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    23 Sep '12 07:30
    Clever.

    But I went down a blind alley. I have seen puzzles where the solution is the board being the other way round from as conventionally presented. So I spent a long time looking at solutions which involving h8B.

    Unless you can show me the position cannot be reached with the Board the other way round......
  11. m
    Standard membermorgski
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    23 Sep '12 12:23
    Originally posted by SwissGambit
    SOLV'D
    Was it also a 6 piece mate on purpose? 😉
  12. S
    Standard memberSwissGambit
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    23 Sep '12 14:361 edit
    Originally posted by Rank outsider
    Clever.

    But I went down a blind alley. I have seen puzzles where the solution is the board being the other way round from as conventionally presented. So I spent a long time looking at solutions which involving h8B.

    Unless you can show me the position cannot be reached with the Board the other way round......
    The convention is that you don't turn the board around unless you can prove that the position is illegal with the traditional orientation.

    Here, if the position is rotated 180°, there are cooks: the last move could have been any of h8=B, g7xQh8=B, etc.





    I don't post 'joke' problems without some kind of hint that conventions will be broken. I don't want to cause people to spend hours looking for a conventional solution when there isn't one.
  13. S
    Standard memberSwissGambit
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    23 Sep '12 14:36
    Originally posted by morgski
    Was it also a 6 piece mate on purpose? 😉
    How cool would that have been? Alas, he has ...Ke7.
  14. m
    Standard membermorgski
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    23 Sep '12 15:16
    Originally posted by SwissGambit
    How cool would that have been? Alas, he has ...Ke7.
    Oops. I should know by now that cursory glances do not cut the mustard on this forum 🙂
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