[Retros] 50 moves rule

[liskov at im.bas-net.by]

Dear retro-friends,

Concerning the notions of "essential progress" and "position" (and its
repetition) let me recall the famous chess problem of N.Petrovic (The
Problemist, 1959, 1 Pr.; P1012540):
 [r3k2r/p2p4/p1pP2p1/5pN1/5p2/1Q3p2/PP4b1/KB6] #8
1.Qb7! Rd8 2.Qb3 Ra8(2) 3.Bd3 Rh1+ 4.Bb1 Rh8(3!) 5.Qc3! Rh7 6.Qf6. It has
practically nothing to do with retro (and nothing with 50 moves), and for me
its soundness is undeniable forever, regardless of any formulations in any
codex.

Valery Liskovets

raosorio at fibertel.com.ar wrote:


> Seth Breidbart  wrote,

>

> It seems to me that the underlying issue is the definition of

> "position". Is it a photograph of the pieces on the board? That plus

> information as to whose move it is? That plus information as to who

> might be allowed to castle (and on which side) in the future?

> (Consider a position in which White has not castled, his King and

> Rooks have not moved, but it can be proven that there is no future

> play which involves White castling; how does that count?)

>

-------------------------------------------------------------------------------------------------

>

> Good point. i think that "if it can be proven that there is no future play

> which involves

>  White castling" then  white has already lost its  castling right

> (understanding

> right as  a real chance to do  it). This  is  to avoid the "bookkeeping"

> approach

> as  Guus set.

> The same apllies to e.p.  capture if  the  capturing pawn is pinned. There

> were no

> real  chance to make the  e.p.  capture so  this position should count as "no

>  e.p.

> capture right".

>

> Roberto Osorio

>

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