[Retros] Programs for Solving Retro Problems
ralphmerridew at gmail.com
Sun Aug 24 14:27:23 EDT 2008
On Sun, Aug 24, 2008 at 2:16 PM, Mario Richter <mri_two at t-online.de> wrote:
> Here the rule seems to be something like "If a king is in check
> by two enemy pieces, and none of this enemy pieces can interfere
> the checking line of the other piece, than the position is illegal."
> This works in most positions, but forgets the case, that one
> of the enemy pieces may change his shape while retracting -
> by unpromotion.
> e.g. 5QN1/8/5k2/8/8/8/8/7K (w: Qf8 Ng8 Kh1 b: Kf6)
> or 5R1B/8/5k2/8/8/8/8/7K (w: Rf8 Bh8 Kh1 b: Kf6)
> 'Retractor' rejects the above positions with the message:
> "Error: This position places your king in an illegal
> double check."
Does it also run into trouble with detecting an un-en passant?
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