[Retros] rights & ocassions /answering Andrew

[Joost de Heer]

On 05/15/2014 07:58 PM, Kevin Begley wrote:
> Hi Guus,
>
> Thank you for the clarification.
> I fully agree that all assumptions should be explicitly stated,
> somewhere in the Codex.
>
> However, there seems to be some confusion concerning the state of a
> position.
>
> An orthodox chess position may be reduced to the following description:
> 1) the diagram (board orientation, and placement of all pieces upon it),
> 2) the set of all castling rights,
> 3) the set of en passant rights, and (the one everybody forgets),
> 4) the dead-reckoning consideration (if no help-win exists, however you
> define win, the game is over).
>
> The above information is both necessary and sufficient to determine the
> set of all legal moves, in any position; therefore, the above
> information forms a basis for the position.
>
> Beyond this basis (the state of a position), there also exists some
> attributes of a position...
> For example, the counters (50-move counter, and 3-move repetition
> counter) constitute an attribute of the position.
> Alteration of these counters does not impact the the basis (or state) of
> the position -- the attributes have no impact upon the set of legal move
> possibilities in said position; they only have an impact upon the
> resulting game outcome.
>
> It is important to separate the aims and goals of a given chess game (or
> problem), from the rules of legal movement, for said game.
> And, the people who write the rules/Codex should know how to express
> these rules from a fairy chess perspective (accounting for varying
> stipulations, aims, goals, etc)...
>
> With regard to the second point (castling rights), just consider how
> orthodox chess skews the proper understanding:  in orthodox chess,
> castling rights are reduced to a set of four information bits:
> 1) white has K-side castling rights?
> 2) white has Q-side castling rights?
> 3) black has K-side castling rights?
> 4) black has Q-side castling rights?
> (each question can be answered by YES/NO, with the default being YES,
> unless spoiled by retro-analysis).
>
> But, the people who write the Orthodox Codex mistakenly believe that
> this information is fundamental to a position, when it absolutely is not!
> The programmers who develop a more encompassing representation (e.g.,
> including Circe/Anticirce forms, wherein castling rights may be renewed
> when units are reborn onto their game-array squares) must all appreciate
> that the above 4-bits are a fiction; actually, 6-bits of information are
> necessary to completely characterize castling rights in a position:
> 1) white King has castling rights?
> 2) white K-side Rook has castling rights?
> 3) white Q-side Rook has castling rights?
> 4) black King has castling rights?
> 5) black K-side Rook has castling rights?
> 6) black Q-side Rook has castling rights?
>
> This example is just one reason (of many) that I've had to constantly
> remind the orthocentric composers to return to the fundamental truths
> (and establish sound definitions).
> It is why I have advocated for a Fairy Codex, for years -- not only
> improve the prospects for fairy chess, but also to clarify orthodox.
> You really don't understand the rules of a language, until you encounter
> the rules of other languages -- so it is with the rules of chess.

This still doesn't answer one of the questions: If all the paths towards 
the actual castling will result in a triggering of either the 50-move 
rule or the 3-fold repetition rule (which should be automatic in chess 
composition, since there is no one to claim), does the castling right 
exist or not?

And a small sidenote: castling rights and castling have nothing in 
common in a game. You can castle in a game even if you don't have the 
right, since illegal moves are allowed until there is a correct claim of 
illegality. See e.g. 
http://timkr.home.xs4all.nl/records/recordstxt.htm#greatest%20number%20of%20castlings

Joost