[Retros] DR vs forced ep: what rule predominates?

Rol, Guus G.A.Rol at umcutrecht.nl
Wed Aug 29 14:41:00 EDT 2007

This is an interesting way to present Otto's question and I suggest the
situation can be made even worse. Suppose the position is NOT YET dead
after the e.p. move but it will die prematurely if anyone attempts to
accomplish "the validation move". Makes Joost's question even more

I have my own - at this point in time certainly unique - view on the
analysis of this scenario. Nothing that happens in an
AP-validation-sequence has any relation to obligations or objectives of
the players. Well, it may from the viewpoints of the (fictitious)
players, but not from the viewpoint of the rules/conventions. As an
example of the distinction between these approaches notice that the
rules do not differentiate a selfmate game from an orthodox game even
when the objectives of the players are widely apart.

The only thing that matters in AP-validation are the variants that the
players are willing to manifest on the board (for whatever their
purposes are). If all those variants implement the validation
requirement then the AP-move is considered OK.

The formal rule evaluator acts in this process as "a witness" which,
having missed the first part of the game, now attempts to make up for
that by gathering decisive evidence. It asks of the players "show me all
the valid variants both of you are willing to co-create" and then I will
tell you whether or not I accept/reject the whole bunch plus the e.p.
move based on a formal validation criterium. Rules are not interested in
the intentions of players.

The "witness-evaluator" does not care for the reasons that the players
are (un)able or (un)willing to manifest the validation criterium, it
only cares that the validation does actually manifest. If the players,
even when willing to help each other, are barred from that manifestation
because of some stupid repetition rule or an even more stupid DR-rule,
too bad for them. The evaluator is not interested in arguments, only in
manifestable states that provide decisive evidence.

So, that is my opinion on Joost's situation. The DR-rule prevents the
manifestation of the validation criterium of the e.p. capture and the
latter must therefore be rejected for lacking the required

Guus Rol.

-----Oorspronkelijk bericht-----
Van: retros-bounces at janko.at [mailto:retros-bounces at janko.at] Namens
Joost de Heer
Verzonden: woensdag 29 augustus 2007 12:23
Aan: The Retrograde Analysis Mailing List
Onderwerp: Re: [Retros] DR vs forced ep: what rule predominates?

Theoretically one could have the following situation: An en passant
capture needs to be validated by an AP move, but this AP move is
impossible because the position after the ep move is dead. Would that
that the ep move is illegal, because its legality can't be proven, even
with AP logic?

Practically, I doubt such a position exists.

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