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Posers and Puzzles

Posers and Puzzles

  1. 26 Mar '08 01:41


    Construct a game which ends in the above position.
  2. Standard member irontigran
    Rob Scheider is..
    26 Mar '08 03:55
    Originally posted by David113
    [fen]8/3ppp2/6p1/6p1/6nB/1PPPP1P1/3PPk2/1bn1bqrK[/fen]

    Construct a game which ends in the above position.
    1.Nc3

    tbc...
  3. 26 Mar '08 11:44
    Originally posted by irontigran
    1.Nc3

    tbc...
    A journey of a thousand miles begins with a single step.

    - Lao Tzu
  4. 26 Mar '08 15:19
    This problem was posted over 13 hours ago, and SwissGambit fifn't post a solution yet. This is a shame.
  5. Standard member SwissGambit
    Caninus Interruptus
    26 Mar '08 16:50
    Originally posted by David113
    This problem was posted over 13 hours ago, and SwissGambit fifn't post a solution yet. This is a shame.
    Hahaha. Sorry, laptop crashed last nite and restoring it became top priority.
  6. 26 Mar '08 17:46
    Originally posted by David113
    This problem was posted over 13 hours ago, and SwissGambit fifn't post a solution yet. This is a shame.
    fifn't = didn't, up to multiplication by a constant
  7. Standard member SwissGambit
    Caninus Interruptus
    26 Mar '08 18:39
    Originally posted by David113
    [fen]8/3ppp2/6p1/6p1/6nB/1PPPP1P1/3PPk2/1bn1bqrK w[/fen]

    Construct a game which ends in the above position.
    12 Black units + 4 wP captures = 16

    ...Rg2xg1+ can't be the last move, because then there is no way to unlock the SE corner. Last move must have been h2xg1=R+, so

    9 White units + 7 wP captures [h2 came from c7!] = 16

    All units were either captured by pawns, or are present in the diagram. Color-sensitive captures: wB must have died on g6 - no other light square available.

    Before my laptop crash, I was trying to decide if White promoted the missing h-pawn or not. I have concluded that both possibilities work, and the problem is cooked.

    Solution 1: The h2 pawn did not promote, but rather was captured on h2.
    The advantage is that I can uncap h7xg6 immediately. The only worry is getting the wRh1 home, so...
    Retract 1...h2xRg1=R+ 2.c2xRd3 h7xBg6. Both sides have free pieces to move now, so I will just show the general plan of retraction rather than plod through move by move.
    -bNg4 goes home. bQ exits via h3 to a1, and unpromotes.
    -bPa steps back far enough to allow a2xBb3.
    -Black gets Bb3 out of the way and unpromotes Bb1.
    -bPb steps back far enough to clear the way for White pieces.
    -bK to f1, wR to g2, bBe1 to g1, bK to e1 lets wR exit via f-file. wK exits via h3 and heads to Qside.
    -bK exits via h3 and returns home.
    -wR returns home to h1.
    -wBg6 returns home to f1.
    -g3 pawn steps back and lets Bg1 return home.
    -Rd3 returns to h8.
    The position is obviously legal at this point [has been for quite some time].


    Solution 2: White promoted his h2 pawn.
    Retract 1...h2xNg1=R+ 2.Nf3 Qh3. Again, both sides have free pieces to move, so let's think in plans and not move-by-move.
    Black obviously has to wait on the g6 uncap until the pawn unpromotes, so...
    -Ng4 and Qh3 return home. Nf3 runs around.
    -bK to f1, bBe1 to g1, bK to e1 allows the escape of the Kings as in sol. 1.
    -f2xBe3! uses Black's promotional possibilities to help White. Be3 goes home. g6 steps back.
    -wN goes to h8 via g6, then unpromotes.
    -wPh steps back to h5.
    -c2xRd3 puts a Rook on the board, which returns home to h8.
    -g5 steps back, then h7xBg6 puts wB on board.
    -wBg6 returns home. g3 steps back.
    -wPh2 uncaptures every missing White piece [Q, 2R, 2N], returning home to c7.
    -all the White pieces just uncapped scatter to allow bBg1 to travel to a1 and unpromote.
    -bPa steps back, a2xBb3, Bb3 clears, unpromote b1, bPb steps back etc, just like sol 1.
    Again, an obviously legal position.
  8. Standard member adam warlock
    Baby Gauss
    26 Mar '08 18:45
    Originally posted by David113
    fifn't = didn't, up to multiplication by a constant
  9. 26 Mar '08 18:53
    Originally posted by SwissGambit
    12 Black units + 4 wP captures = 16

    ...Rg2xg1+ can't be the last move, because then there is no way to unlock the SE corner. Last move must have been h2xg1=R+, so

    9 White units + 7 wP captures [h2 came from c7!] = 16

    All units were either captured by pawns, or are present in the diagram. Color-sensitive captures: wB must have died on g6 - no oth ...[text shortened]... ears, unpromote b1, bPb steps back etc, just like sol 1.
    Again, an obviously legal position.
    Ok, I'll try to fix it like this: in the initial position, move the black bishop from b1 to d1. Is the problem OK now?
  10. Standard member SwissGambit
    Caninus Interruptus
    26 Mar '08 19:19
    Originally posted by David113
    Ok, I'll try to fix it like this: in the initial position, move the black bishop from b1 to d1. Is the problem OK now?
    Yes, that fixes it.