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

[Nicolas.Dupont at math.univ-lille1.fr]

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

>>> b) PG 7.5



> I had found what I think is the intended solution (with wKa jumping over

> bKa at move 6)


The intended solution is :

1.Nf3 Nf6 2.KAg4 Nd5 3.Né5 KAd4 4.Nd3 Nb4 5.KAa4 KAd1 6.Nç5 KAd8 7.Nb3 Nd5
8.KAd1

What we missed is to explore the possibility of a kangaroo jumping 5-fold,
as in Mario's cooking line...

This possibility is avoided in the following :


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

>> PG 6.5

>> 2 solutions


DON'T READ IF YOU WANT TO FIND BY YOURSELF

The intended solution is :

1.Ng1-f3 Ng8-f6 2.KAd1-g4 KAd8-d1 3.Nf3-d4 KAd1-d5 4.Nd4-f5 Nf6-e4
5.Nf5-g3 Ne4-d6 6.KAg4-g1 KAd5-d8 7.KAg1-d1

As it is one move less than the previous cooked problem, we tried Popeye
(with huge memory). We were surprised but pleased to see appear the
following curious second solution (clearly a non-human one !) :

1.Ng1-f3 Ng8-h6 2.KAd1-g4 Nh6-f5 3.Nf3-g5 KAd8-h4 4.Ng5-e4 KAh4-d4
5.Ne4-g3 Nf5-d6 6.KAg4-g1 KAd4-d8 7.KAg1-d1


> 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.


Indeed this is an interesting possibility.

Best,

Nicolas.