[Retros] Again about En Passant Chess

andrew buchanan andrew at anselan.com
Sun Mar 25 09:20:14 EDT 2007

The generalized e.p. rule is interesting.

It reminds me of an old joke position which I think was something like
this: 2b5/1kBp4/pP6/2P5/7p/6bK/8/5B2. I don't know who made the

The idea is 1.Bg2+ d5# (forced) *then* White plays 2.cxd6ep#!? claiming
that Black's d pawn never reached d5 to block the check because it was
captured on d6. Of course, there is no real paradox here because

I was trying to thinking of a metaphor for en passant chess without
replacement which avoids the time paradoxes. The first ideas were of
deep sea divers trailing air tubes behind them. Or robots who are
plugged into the mains electricity supply. But neither of these
captures the feature that the opportunity to capture ep is only a
temporary one.

The best metaphor to drift into my mind is that each unit is in fact a
military regiment trailing supply wagons behind it after it moves. The
supply wagons are slower than the regiment, and take a short time to
catch up with the main force. An army can be destroyed either by
capturing it directly *or* by destroying its lagging supply wagons.
Knights are exceptional: as cavalry units in that they live off the
land and require no wagons.

This metaphor ironically returns to the military origins of chess as a
wargame. Perhaps once upon a time universal en passant was the standard
rule for the game, and what we have today for pawns is just the last
vestige of that ancient and realistic rule... :-)

all the best,

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