[Retros] A retro in the fairy tournament, Messigny 2010

Noam Elkies elkies at math.harvard.edu
Sun Jun 13 16:36:04 EDT 2010

Nicolas.Dupont at math.univ-lille1.fr writes:

>> Thierry Le Gleuher & Nicolas Dupont

>> 3-4 Prize ex aequo

>

>> rnbkakb1r/pppppppp/8/3n4/8/1N6/PPPPPPPP/RNBKaKB1R

>> a) SPG 2.5

>> b) PG 7.5

> Cooked by Mario Richter :

That's a pity. Almost an independent second solution, but
Black's last three moves are interchangeable. I had found
what I think is the intended solution (with wKa jumping over bKa
at move 6); while playing with some of the other possibilities
I explored along the way, I ran across the start of Mario's cook,
but didn't think to try applying it back to the original
Le Gleuher / Dupont position. Could it be that the same opening makes
the position after 1 Sg1-f3 Sb8-c6 2 Sf3-d4 also a unique PG in 6.5 !?

> Here is a Popeye C+ corrected version :

> rnbkakb1r/pppppppp/3n4/8/8/6N1/PPPPPPPP/RNBKaKB1R

> PG 6.5

> 2 solutions

That's nice too, though I think it's different enough from the original
setting that it's more a "variation"(?) than a "version". The same
is true of my proposal above (if sound), though it's closer in having
the same format (SPG in n, PG in n+5 with (I hope) a unique solution
in both phases).

You've found a neat new corner of fairy PG-land (Ka's instead of both Q's,
no captures or P/B moves); it seems to be sufficiently circumscribed
that -- even allowing for K and R moves -- Francois Labelle should be
able to quickly carry out an exhaustive analysis and find all the
interesting proof games that it supports.

NDE