[Retros] Exact chess? (Re: Variant PG wanted)

Noam Elkies elkies at math.harvard.edu
Wed Jan 27 19:25:58 EST 2010

Nicolas.Dupont at math.univ-lille1.fr writes:

> A couple of years ago, I had a related idea : playing "exact chess".

> This goes as ordinary chess, but the first player who makes a move

> such that the resulting position is not exact loses the game !

I've seen this already under the name "proof game chess";
there a move that left a non-uniquely-reconstructible position
was deemed illegal, and the first person to have no legal move
in this sense loses -- which can also be the case as a result of
checkmate or conceivably stalemate. I have a dim recollection that
this was used to get a PG with 6 Bishop promotions where 5 was the
orthodox record.

I think there was also a suggestion that if the game was actually played
then White should have an easy win. If there were nevertheless a
standard opening book then any opening in it would automatically
satisfy Andrey's condition :-)


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