From: hwr@intercal.com (Hanon W. Russell)
Newsgroups: rec.games.chess
Subject: History of the 50-move rule
Date: Wed, 25 Nov 1992


A reader has inquired about the history of the 50-move rule,
wondering if the move was put into effect in response to a
"proof" in the 1930's that allegedly demonstrated that without
the rule, infinitely long games were possible (we assume that
this implied the best possible moves by both sides). Although
we are decidedly non-mathematical (we are known to break out
with severe cravings for ice cream and and hot fudge when
subjected even to the threat of exposure to math books) we
undertook a bit of historical research. The source, the newly
released second edition of Whyld and Hooper's magnificent
tome "The Oxford Companion to Chess" (which by the way, shall
be duly reviewed here, possible when we finish this hot fudge
sundae...)

>From OCC: "The law existed in shatranj [whose golden age was
the 8th-9th centuries, A.D.- HWR] as a 70-move version, and
since then the intention has always been the same, that is, to
counter the obstinacy of one who continues playing in an unwinnable
position. In 1561 Ruy Lopez said that 50 moves was enough, but 
Carrera thought this too generous and that 24 moves was right. On
the other hand LaBourdonnais argued for 60 moves. By the 19th
century a request for a count could be made only in specific
endgames (not always the same in the various sets of laws). The
count began only when the claim was made and was not annulled
by a capture or a pawn move. Anomalies could arise such as if
the queen were captured near the end of a 50-move count in an
endgame K+Q v. K+R the result would still be a draw if mate was
not effected in the remainder of the fifty moves. The laws used
at London 1883 tournament stated that a pawn move or a capture
annulled the count, but did not offer retrospective counting when
the claim was first made."

HWR