[Retros] How many times could a Diagram be repeated during aproofgame?

[Rol, Guus]

Hi Francois,
 
I made an error in mixing up 'full' and 'single' moves. You are right in
your 89 moves. No worries about the proximity of the 50 moves rule
though since the position occurs equally with both sides on move.

Cheers, Guus.



> -----Oorspronkelijk bericht-----

> Van: retros-bounces at janko.at [mailto:retros-bounces at janko.at] 

> Namens Francois Labelle

> Verzonden: maandag 4 juni 2007 19:42

> Aan: The Retrograde Analysis Mailing List

> Onderwerp: Re: [Retros] How many times could a Diagram be 

> repeated during aproofgame?

> 

> 

> I'm trying to correct the calculations of Yefim and Guus:

> 

> Number of repeated diagrams:

> 

> 5 (castling rights) * 2 (repetition) * 2 (whose turn)

> + 1 (en passant, must be the initial position)

> + 1 (repeat one position 3 times)

> = 22

> 

> Number of moves necessary:

> 

> 5 (castling rights) * (2 + 2.5 + 2)

> (moves for: repetition, turn change, repetition)

> + 4 (castling right changes) * 2 (moves per castling right change) 2 

> + (moves for en passant) 2 (moves to repeat one position 3 times)

> = 44.5 ...which is fortunately less than 50 moves.

> 

> Feel free to correct me!

> 

>  	Francois

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