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Subject: Re: How many positions in 4 or 5 piece endgames?

Author: Ernst A. Heinz

Date: 10:04:17 10/13/98

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On October 13, 1998 at 12:23:29, John Coffey wrote:
>
>How many possible positions are there in all 4 or 5 piece endgames?
>I am thinking that it must be between billions and trillions.
>do such endgames take advantage of symetry?

If you do not discount illegal positions there are 64^X possible constellations
of X pieces. By removing symmetries, not placing more than one piece on the same
square, and not placing the Kings directly beside each other, you can easily
reduce this number to:

  (a)   462 * 62 * 61        for 4-piece endgames without Pawns,
  (b)  3612 * 24 * 62        for 4-piece endgames with a single Pawn,
  (c)  3612 * 24 * 47        for 4-piece endgames with 2 Pawns (no en-passant),

  (d)   462 * 62 * 61 * 60   for 5-piece endgames without Pawns,
  (e)  3612 * 24 * 62 * 61   for 5-piece endgames with a single Pawn,
  (f)  3612 * 24 * 47 * 62   for 5-piece endgames with 2 Pawns (no en-passant),
  (g)  3612 * 24 * 47 * 46   for 5-piece endgames with 3 Pawns (no en-passant).

I have submitted an article to the ICCA Journal which describes the according
index schemes among other things.

=Ernst=



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