George Duke wrote on Sat, Jul 14, 2007 11:33 AM EDT:
By more tools to work with, there exist more solutions. Winkelspecht's
1999 Divergent Chess Rook, Winther's 2006 bifurcation piece Murmillo, and
Falcon extension (1996 copyright) Dragon all three key for 2-player immobilization. 8x8 solution shows all White & Black pieces' having no legal moves, whoever first, in legal initial set-up, Kings back-ranked.
8 ____F____W____L____K____ ____ ____L P,p = Berolina Pawn
7 P____ ____P____ ____P____ ____P____ D,d = Dragon, required 5-square
6 V____P____ ____P____ ____P____V____P multipath
5 M____ ____P____ ____P____ ____M____D V,v = Divergent Ch. Rook moves
4 d____p____ ____p____ ____p____ ____m as R, captures as Bishop
3 p____v____p____ ____p____ ____p____v M,m = Murmillo, moves Bishop,
2 ____l____ ____p____ ____p____ ____p only if capturing turns
1 f____ ____ ____k____l____ ____l____w 45-degrees for 'bounce-
a b c d e f g h capture' second leg
F,f = Ferz; L,l = Alfil
W,w = Wazir
White: If King d1-c2, then V-g6 has path, illegal.
If King d1-e2, then V-a6 has path, illegal.
If King d1-c1, then Dragon has pathway h5-g4-f3-e2-d1-c1.
Black: If King e8-f7, then v-b3 has path, illegal.
If King e8-d7, then v-h3 has path, illegal.
(2) If King e8-f8, then Dragon has pathway a4-b5-c6-d7-e8-f8.
By more tools to work with, there exist more solutions. Winkelspecht's 1999 Divergent Chess Rook, Winther's 2006 bifurcation piece Murmillo, and Falcon extension (1996 copyright) Dragon all three key for 2-player immobilization. 8x8 solution shows all White & Black pieces' having no legal moves, whoever first, in legal initial set-up, Kings back-ranked. 8 ____F____W____L____K____ ____ ____L P,p = Berolina Pawn 7 P____ ____P____ ____P____ ____P____ D,d = Dragon, required 5-square 6 V____P____ ____P____ ____P____V____P multipath 5 M____ ____P____ ____P____ ____M____D V,v = Divergent Ch. Rook moves 4 d____p____ ____p____ ____p____ ____m as R, captures as Bishop 3 p____v____p____ ____p____ ____p____v M,m = Murmillo, moves Bishop, 2 ____l____ ____p____ ____p____ ____p only if capturing turns 1 f____ ____ ____k____l____ ____l____w 45-degrees for 'bounce- a b c d e f g h capture' second leg F,f = Ferz; L,l = Alfil W,w = Wazir White: If King d1-c2, then V-g6 has path, illegal. If King d1-e2, then V-a6 has path, illegal. If King d1-c1, then Dragon has pathway h5-g4-f3-e2-d1-c1. Black: If King e8-f7, then v-b3 has path, illegal. If King e8-d7, then v-h3 has path, illegal. (2) If King e8-f8, then Dragon has pathway a4-b5-c6-d7-e8-f8.