Author: Ricardo Gibert
Date: 08:36:09 11/10/99
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On November 09, 1999 at 22:04:30, Bruce Moreland wrote: >On November 09, 1999 at 18:42:24, Andrew Dados wrote: > >>Hello, Scott! >> Bad news here: 2 Knignts can not mate lone King... You may have found some >>positions where 2 N mate King+Pawn; not sure what is longest mate there, but >>there are (KNN vs KP) positions where definetely more then 50 moves without >>progress (moving a pawn or capture) is needed. As I remember fide adjusted 50 >>move rule for this case (and some others) and allows now 150 moves with no >>progress for KNN vs KP (correct me if I am wrong here). >> >>-Andrew- > >Black king h8, white king h6, white knight f6, white knight h4. White to move >mates in one with Ng6#. > >It is not a forced mate, because black's previous move must have been Kg8-h8. >He simply could have played Kg8-f8 or Kg8-f7 and avoided the mate. > >bruce A final position where 2 Ns mate a king _can_ be forced (by transposing KNNK via a series of exchanges). I have a recollection of an endgame study by Troitzky that ends this way. There also endgame studies where the final position has K+B mating K+B, etc. There is a possible bug with many programs that declare such endings as draws when a mate in one may still be possible. I believe that Fritz4 is one program that behaves erratically when cofronted by such examples. There are no mate in twos with just KNNK that can be forced of course.
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