From: "Randal J. Andrews" <tiger22 <at> IX <dot> NETCOM <dot> COM>
Date: 17 apr 1996
Subject: Mate by pawn drop illegal

>My interest was in the historic significance of this strange rule, but
>it seems that my argument for this rule to be inconsistent clouded the
>issue of the rules. Furthermore, it seems that nobody knows the logic
>behind making a pawn drop mate illegal. This is a pity, because I
>really would like to know. To me this rule is a small blemish on a
>perfect game and I would sleep better if I would know there is a
>logical explanation ;-).
>
I don't know why it's illegal.  However, a possible reason occurred to
me.  As the endgame approaches, both players are likely to have pawns
in hand.  Especially, in games of the great masters, they seem to toss
pawns back and forth like hot potatoes.  Perhaps, it was felt that
allowing mate with a pawn drop lessened the skill of the game.  Pawns
are just so numerous by the endgame that no skill is required to have a
few in hand. Thus, the proverb: "If there is a mate with a Pawn drop,
there is a legal mate as well" forces the player to look for that
clever sequence where the pawn is not used last.