1. Berks.
    Joined
    27 Nov '04
    Moves
    41991
    24 Oct '07 13:04
    White can now extract the rooks by moving his K between f8, f7 and e8. R to f8 then out down f-file.

    Black can keep moving his rook between a7, a8 and b8. The a-pawn cannot retract to a3 as it would trap the wK. Think it's best kept on a4 as it allows the bR to be free to capture the wB on c1.

    wK escapes via d8 - c7 - b6 - b5 - c5.

    So to back something like:

  2. Berks.
    Joined
    27 Nov '04
    Moves
    41991
    24 Oct '07 13:171 edit
    Edit: Ignore this, I made a crucial mistake in how to uncapture the bB.
  3. Berks.
    Joined
    27 Nov '04
    Moves
    41991
    24 Oct '07 13:49
    I need to get the bR to h8. This must be done via O-O as the R must be on the back rank before the g6 and h7 pawns can be released.

    So:



    The wN on g8 I've temporarily, and probably against form removed, it's retracted a couple of moves back to whence it came.

    Clearly from here f7xg6 and then g6xPh7 have to be retracted leaving the opportunity for black to uncastle. The B on f8 must have been taken by a wN.

    Because c2xd3 could have been a very early move no such problem obtaining access for a bR to capture on c1.

    The two bN simply need enough moves to move into a capturing position. He can use (g8 - h6 - f5) and (b8 - a6 - b5 - d3) for a total of five. Possibly giving check in the process.

    h3, h4, Rh1/2/3 and Ra1/b1 can act as safe waiting moves for white.

    White needs to get a N to g8 and one to f8 before being captured, which can't just be straight to g6 as the wP on h7 must already be in-situ, meaning black can't either then castle, nor move to h8.

    Quickest way to g8 is four moves (b1 - c3 - d5 - f6 - g8) as it is to f8 (g1 - f3 - d4 - e6 - f8).

    This wN must be captured, the quickest possible is still on g6, but it cannot go directly, so needs to be (f8 - e/g6 - f4 - g6) making three moves.

    Which makes 11 wN moves to get into these positions. A wN cannot go from f8 to g8 without taking at least five moves due to h7, d7 and e7 being continually unavilable, taking 3N moves to d6 from b1 this would be longer.

    Therefore:

    4 moves - wNb1 to g8
    4 moves - wNg1 to f8
    3 moves - wNf8 to g6
    2 moves - bNg8 to f5
    3 moves - bNb8 to d3
    3 moves - wNg8 to b4
    4 moves - bNc1 to f8

    Total = 23 moves
  4. Standard memberSwissGambit
    Caninus Interruptus
    2014.05.01
    Joined
    11 Apr '07
    Moves
    92274
    24 Oct '07 16:35
    Originally posted by Peakite
    4 moves - wNb1 to g8
    4 moves - wNg1 to f8
    3 moves - wNf8 to g6
    2 moves - bNg8 to f5
    3 moves - bNb8 to d3
    3 moves - wNg8 to b4
    4 moves - bNc1 to f8

    Total = 23 moves
    Yes, 23 moves is indeed the answer. Well done!

    It's easy to miss the 'extra' four moves to put bBf8 back on the board.
  5. Berks.
    Joined
    27 Nov '04
    Moves
    41991
    30 Oct '07 23:31
    Originally posted by SwissGambit
    Yes, 23 moves is indeed the answer. Well done!

    It's easy to miss the 'extra' four moves to put bBf8 back on the board.
    I missed that for a while (my unedited last post declared 19 moves).

    A very challenging one, quite tricky at first to see how to get a second place piece into play. Spent too long trying to get the position released quickly.

    A good problem, and nice to see one round here, sadly chess problems (and interested solvers) are in too short a supply these days.
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