[Retros] Petrovic #8 is C+

[Rol, Guus]

Repetition rules are generally fine. Codex Article 18 provided the
automaticity desired by composers and note [21] affirms the requirement
of identical positional properties. The only bug remaining is that the
option to claim a draw has not been expressly erased from the default
option list. The idea of conventions should not be to add ambiguity and
confusion but to remove them! The fear of losing creations in that
process is unwarranted since composers have been granted unlimited
powers to bend rules and stipulations.

Note: Rules are loosely 'musts/mustnots' and conventions
'shoulds/shouldnots'(preferences). It is doubtful that there is much
meaningful difference between the two in chess composition. With the
extensive rule autonomy of the composer, the status of all rules reverts
more or less to being 'conventional' or 'default'. The subtle
distinction between rule and convention to justify certain views on
compositions appears like hocus-pocus to me and tends to obscure the
issues.

Guus Rol.


Article 18 - Repetition of Position

A position is considered as a draw if it can be proved that an identical
position [21] has occured three times in the proof game combined with
the solution.

[21] Identical position means the same kinds of pieces on the same
squares with the same move rights.




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

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

> Namens Noam Elkies

> Verzonden: donderdag 11 januari 2007 5:53

> Aan: retros at janko.at

> Onderwerp: [Retros] Petrovic #8 is C+

> 

> 

> Valery Liskovets <liskov at im.bas-net.by> wrote:

> 

> > 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.

> 

> Thank you for this -- as it happens I had been looking for 

> that problem only a few days before but could not locate it.

> 

> I'm happy to report that this classic is C+.  It took Popeye 

> 3.41 more than 4 hours to verify it!  With the "Variation" 

> option, it produces 700+ moves; to be sure, some are 

> repetitive(*) but there are still quite a few nontrivial 

> side-lines to check, and the 4-hour timing is some measure of 

> the difficulties Petrovic must have faced in constructing and 

> checking this problem.

> 

> (*) For isntance, it takes 32 lines to give the mate in 2 

> after 1...0-0? 2 Qxd7.  Even so, some lines are omitted, such 

> as 3...Kd8, which defeats the threat 4 Qf7+ but allows the 

> short mate 4 Nf7+ Ke8 (Kc8? 5 Bxa6#) 5 Nxh8 and mate next (I 

> also checked with Popeye that there is no other way for White 

> to mate in time after 3...Kd8).

> 

> NDE

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