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  1. #1
    CC resident nutcase Trent Parker's Avatar
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    Mate in ~21 moves!

    FEN Viewer


    White to play and force mate in twenty something moves.

  2. #2
    CC International Master Miranda's Avatar
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    twenty something?

    I'm not even going to try.
    It's time for man to enter the Solar System - Dan Quayle

  3. #3
    CC resident nutcase Trent Parker's Avatar
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    Come on Miranda! its all forced!

  4. #4
    CC International Master Miranda's Avatar
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    Um.... black bishop gives check?
    It's time for man to enter the Solar System - Dan Quayle

  5. #5
    CC International Master Miranda's Avatar
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    IDK about you, but to me, forced mate = check, check, check (repeat as many times as needed) checkmate.

    It's time for man to enter the Solar System - Dan Quayle

  6. #6
    CC Grandmaster
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    I got it in 19 moves, might've missed some better defence without the chess board in front of me, even I can't see where black could play better

    1. Be3+ Kb1
    2. Bh6 b5
    3. Ke7 b4
    4. Kf6 b5
    5. Kg5 Kc1
    6. Kf5(or Kg4)+ Kb1
    7. Kf4 Kc1
    8. Ke4(f3)+ Kb1
    9. Ke3 Kc1
    10. Kd3+ Kb1
    11. Bd5 b3
    12 .Bxb3 b4
    13. Bd5 b3
    14. Kc3 Ka2
    15 Bxb3+ Kb1 (15...Ka3 16.Bf8#)
    16. Be3 h5
    17. Bc4 h4
    18. Kb3 h3
    19. Bd3#
    If 3...b6, then Kf6-f5-f4 and checkmate one move earlier.
    For private coaching (IM, four times VIC champion) call or SMS 0417519733
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  7. #7
    CC International Master Kaitlin's Avatar
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    Cool

    Waits patiently for someone to put a PNG up :twiddlesthumbs:
    .. this Caketin is full of little spiders and watermelon seeds.....

    ..Chess is all about fear and psychology

    ..Chess is like an exam..... you havent studied for

    ..If you're good at Chess it means you are very intelligent and could potentialy do great things
    ..... but that you might have wasted that playing way too much chess

  8. #8
    CC Grandmaster
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    I don't know how to do pgn from the setup position (e.g. not initial one). I put it in chessbase, saved as pgn and tried to upload, but uploader ignores the FEN
    For private coaching (IM, four times VIC champion) call or SMS 0417519733
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  9. #9
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    Quote Originally Posted by Igor_Goldenberg
    I got it in 19 moves, might've missed some better defence without the chess board in front of me, even I can't see where black could play better

    1. Be3+ Kb1
    2. Bh6 b5
    3. Ke7 b4
    4. Kf6 b5
    5. Kg5 Kc1
    6. Kf5(or Kg4)+ Kb1
    7. Kf4 Kc1
    8. Ke4(f3)+ Kb1
    9. Ke3 Kc1
    10. Kd3+ Kb1
    11. Bd5 b3
    12 .Bxb3 b4
    13. Bd5 b3
    14. Kc3 Ka2
    15 Bxb3+ Kb1 (15...Ka3 16.Bf8#)
    16. Be3 h5
    17. Bc4 h4
    18. Kb3 h3
    19. Bd3#
    If 3...b6, then Kf6-f5-f4 and checkmate one move earlier.
    I got this too. Since the question asks for 21 moves, perhaps white can shuffle the light-square bishop along the a6-f1 diagonal until black promotes, then deliver the Bd3# (Or Be2-d1-c2#; or a similar idea depending how far back you move that bishop from b3...).

    Inefficient moves within the logic of chess, but this satisfies the question.

    Incidentally, if black chooses to play b7-b6 instead of b7-b5 then white can mate one move faster; but can still satisfy the question with a shuffle until move 21. That is, so long as black plays h7-h6 etc. If black plays h7-h5 (and continues with ideal play from then on), then white will need to deliver mate on move 20.

    By the same reasoning, the main line given by Igor, and my suggestion to shuffle until promotion, only works with black playing h7-h5. If h7-h6 then white can make the mate on move 21 with the pawn on h2, or shuffle a move longer and do mate on the 22nd move.

    Unless I missed something!?

    I don't see the point for extending the solution beyond best play. Nice concept in the given problem though.

  10. #10
    CC Candidate Master
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    Success!

    PGN Viewer
     

  11. #11
    CC Grandmaster
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    Thanks. So, you put FEN in pgn statement, then it starts from that position.
    For private coaching (IM, four times VIC champion) call or SMS 0417519733
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  12. #12
    CC Grandmaster
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    Quote Originally Posted by black
    I got this too. Since the question asks for 21 moves
    I wasn't looking for white to make it longer, only for black to prolong the agony.
    Interesting, Rybka was puffing for almost half an hour, but came out only with += line and got nowhere near the solution (which is not very difficult for human being). After being humiliated by a computer so many times, I finally felt vindicated.
    Last edited by Igor_Goldenberg; 19-11-2008 at 10:35 AM.
    For private coaching (IM, four times VIC champion) call or SMS 0417519733
    Computer tells you what to play. Good coach explains why.

  13. #13
    CC International Master Miranda's Avatar
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    haha... I would never have seen that. never.

    meh.

    perhaps one day...
    It's time for man to enter the Solar System - Dan Quayle

  14. #14
    CC International Master Space_Dude's Avatar
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    Quote Originally Posted by Kaitlin
    Waits patiently for someone to put a PNG up :twiddlesthumbs:
    Agreed!
    IMABACK

  15. #15
    CC International Master Miranda's Avatar
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    Quote Originally Posted by Tony.K
    Agreed!
    Look at post 10.
    It's time for man to enter the Solar System - Dan Quayle

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