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Posers and Puzzles

Posers and Puzzles

  1. 08 May '08 19:48 / 2 edits


    The excelsior problem, posted by SwissGambit, in which a pawn delivers the mate, reminded me of the above composition.

    White to play and mate the black king.
    BUT:
    1. In the final position the black king must be threatened by a white pawn.
    2. White is not allowed to capture any black unit.
    3. White is not allowed to lose any of his own units.

    This means that wPc2 must somehow reach c6 or c7 without being captured by a black P and without white capturing a black P.
  2. 08 May '08 20:13
    Originally posted by David113
    [fen]6k1/5R2/1p1p1R2/1p1p1N2/1p1p1N2/1P1B1Q2/2P2B2/5K2[/fen]

    The excelsior problem, posted by SwissGambit, in which a pawn delivers the mate, reminded me of the above composition.

    White to play and mate the black king.
    BUT:
    1. In the final position the black king must be threatened by a white pawn.
    2. White is not allowed to capture any black unit. ...[text shortened]... omehow reach c6 or c7 without being captured by a black P and without white capturing a black P.
    c2-c4, with a discovered check from wRa2/wQa2 on bKd2/e2/f2/g2/h2
    c4-c5, with a wR on a6, wQ on f6, bKc6 (all moves leading to the position must have been checks, otherwise b5/d5xc4)
    c5-c6 mate
    or... c6-c7 mate
    or c7-c8=Q mate (if allowed?)?
  3. 08 May '08 21:42
    Originally posted by heinzkat
    c2-c4, with a discovered check from wRa2/wQa2 on bKd2/e2/f2/g2/h2
    c4-c5, with a wR on a6, wQ on f6, bKc6 (all moves leading to the position must have been checks, otherwise b5/d5xc4)
    c5-c6 mate
    or... c6-c7 mate
    or c7-c8=Q mate (if allowed?)?
    I don't know if c7-c8=Q# is allowed; anyway, in the intended solution the pawn is not promoted, so you should do it without a promotion.
  4. Standard member SwissGambit
    Caninus Interruptus
    08 May '08 22:15 / 1 edit
    Originally posted by heinzkat
    c4-c5, with a wR on a6, wQ on f6, bKc6 (all moves leading to the position must have been checks, otherwise b5/d5xc4)
    This is the tricky part. If bK is checked such that he must go to c6, then White's c5 will likely stalemate him [Pc5 has to be protected].
  5. 09 May '08 05:22
    Originally posted by SwissGambit
    This is the tricky part. If bK is checked such that he [b]must go to c6, then White's c5 will likely stalemate him [Pc5 has to be protected].[/b]
    Not so difficult, for example after Kd7 - Qd8+ [supported by some other piece] - Kc6 - c4-c5 [supported by wNd3, probably] - Kb7 - Qd7+ - Ka8 - c5-c6 - Kb8 - ...
  6. Standard member eldragonfly
    leperchaun messiah
    09 May '08 16:02


    c2-c4 you can kiss the pawns off, so it must be something else.
  7. 09 May '08 18:12
    Originally posted by heinzkat
    c2-c4, with a discovered check from wRa2/wQa2 on bKd2/e2/f2/g2/h2
    c4-c5, with a wR on a6, wQ on f6, bKc6 (all moves leading to the position must have been checks, otherwise b5/d5xc4)
    c5-c6 mate
    or... c6-c7 mate
    or c7-c8=Q mate (if allowed?)?
    I'm sorry; after c4 isn't the pawn lost? And what discovered check from which piece on a2? Must be missing something here.
  8. Standard member SwissGambit
    Caninus Interruptus
    09 May '08 18:59
    Originally posted by curseknight
    I'm sorry; after c4 isn't the pawn lost? And what discovered check from which piece on a2? Must be missing something here.
    heinzkat is talking about long-range plans, not immediate moves. He means that white will aim for a setup with wR on a2, and bK on [say] e2. At this point, if there are no other pieces in the way, c2-c4 will check the black King.
  9. 11 May '08 19:48
    Originally posted by SwissGambit
    heinzkat is talking about long-range plans, not immediate moves. He means that white will aim for a setup with wR on a2, and bK on [say] e2. At this point, if there are no other pieces in the way, c2-c4 will check the black King.
    Oh, OK, I get it now. Thanks.
  10. 11 May '08 20:16
    Originally posted by David113
    [fen]6k1/5R2/1p1p1R2/1p1p1N2/1p1p1N2/1P1B1Q2/2P2B2/5K2[/fen]

    The excelsior problem, posted by SwissGambit, in which a pawn delivers the mate, reminded me of the above composition.

    White to play and mate the black king.
    BUT:
    1. In the final position the black king must be threatened by a white pawn.
    2. White is not allowed to capture any black unit. ...[text shortened]... omehow reach c6 or c7 without being captured by a black P and without white capturing a black P.
    This task is fiendish... the walk of the Black King after c2-c4 must completely be executed with checks, the King has to walk from d2 to c6, completely 'guided' over some sort of path White must have made...
  11. 13 May '08 18:33 / 1 edit
    Originally posted by David113
    [fen]6k1/5R2/1p1p1R2/1p1p1N2/1p1p1N2/1P1B1Q2/2P2B2/5K2[/fen]

    The excelsior problem, posted by SwissGambit, in which a pawn delivers the mate, reminded me of the above composition.

    White to play and mate the black king.
    BUT:
    1. In the final position the black king must be threatened by a white pawn.
    2. White is not allowed to capture any black unit. ...[text shortened]... omehow reach c6 or c7 without being captured by a black P and without white capturing a black P.
    Does black have to avoid quicker mates without a pawn (e.g. best play) or can he move Kh8 after Rg6+ for example?
  12. 13 May '08 18:35
    Originally posted by curseknight
    Does black have to avoid quicker mates without a pawn (e.g. best play) or can he move Kh8 after Rg6+ for example?
    White is not allowed to lose any unit.
  13. 13 May '08 18:36
    Originally posted by heinzkat
    White is not allowed to lose any unit.
    It was an example.
  14. 13 May '08 18:44
    Originally posted by curseknight
    It was an example.
    Well I suppose you don't want to work out lots of subvariations for deviation moves by the Black King - in the meanwhile no progression. Anyone else?!
  15. 13 May '08 18:46
    Originally posted by heinzkat
    Well I suppose you don't want to work out lots of subvariations for deviation moves by the Black King - in the meanwhile no progression. Anyone else?!
    Never mind. Honestly.