Chess is basically "capture the king", ie the checkmate rules are consistent in the sense that they are just the "1-move closure" of the "whoever captures the king first, wins" rule. The stalemate rule is the exceptional one in my opinion, because it says that a king not in check but with no move available (including other pieces) is a drawn position. It really should be a win for the stalemater, but this would throw out years of interesting endgame theory, particularly the "opposition" theory, which is nice So in Dan's example, the pinned piece moves to capture the king, exposing his own king yes, but then, the game is over so that doesn't matter Thane Plambeck 650 321 4884 office 650 323 4928 fax http://www.qxmail.com/home.htm ----- Original Message ----- From: asimovd@aol.com To: math-fun@mailman.xmission.com Sent: Tuesday, May 06, 2003 1:09 PM Subject: [math-fun] A proposed new chess rule I don't think this comes up often in practice, but unless I'm mistaken one's king may not be on a square that is attacked by any of the opponent's pieces. AFAIK, this even includes the situation when the said opponent's piece is immobilized due to its being pinned against its own king. Thus a checkmate could occur even when the checkmate hinges on a king's being forbidden to escape to a square "attacked" by an opponent's piece that is at the time immobilized by a king pin. Is this correct? It won't change the course of chess very much, but if this is possible I think the rule should be changed so that the king is allowed to move to any unoccupied square unless the opponent could conceivably "take" the king on that square on the very next move. Comments? --Dan ------------------------------------------------------------------------------ _______________________________________________ math-fun mailing list math-fun@mailman.xmission.com http://mailman.xmission.com/cgi-bin/mailman/listinfo/math-fun

On 6 May 2003 at 16:09, asimovd@aol.com wrote:

I don't think this comes up often in practice, but unless I'm mistaken one's king may not be on a square that is attacked by any of the opponent's pieces.

AFAIK, this even includes the situation when the said opponent's piece is immobilized due to its being pinned against its own king.

That's my understanding of the rules....

Thus a checkmate could occur even when the checkmate hinges on a king's being forbidden to escape to a square "attacked" by an opponent's piece that is at the time immobilized by a king pin.

I think the problem here is that you are viewing 'immobilized' stronger than I took the rule. As I understood the overarching rule, it was simple: you cannot commit suicide in chess... if you want the game to end, you must resign. From that view, a 'pinned' piece cannot move not because of some fancy rule about pinning, but only because moving the piece would be a suicide with the opponent's next move... *IF* the opponent has a next move! In the case of moving the king to a square attacked by a pinned piece, you will have *already*lost* [because your king was taken], and so you'll not get a chance to execute the taking of the other side's king from the unpin and so that taking was legal [since it was not a suicide move]. /Bernie\ -- Bernie Cosell Fantasy Farm Fibers mailto:bernie@fantasyfarm.com Pearisburg, VA --> Too many people, too few sheep <--