[Retros] Pawn to-the-8th-rank mates

[andrew buchanan]

Hi Nicolas,

Nice matrix for a1N#. Surprisingly, it can be sharpened still further
though:

"Andrew Buchanan & Nicolas Dupont"
rn1qkbnr/p1pppppp/8/8/P2Q4/2P5/1PKPbPPP/nNB2BNR
SPG 7.0

And since Joost reminded us all of the concept of a *pin* my a1/8#R/Q
answers are also subject to improvement:

"Andrew Buchanan & Joost de Heer"
R1kr1bnr/1ppnpppp/3q4/3p4/8/7Q/PP1PPPPP/RNB1KBNR
SPG 6.5

(& sim with wQa8)

(Order of names taken to be alphabetical - hope this is OK.)

Regards,
Andrew Buchanan

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


> Dear Andrew and all,

> 

> > Very

> > possible that faster versions still yet exist, especially the N

> one...

> 

> > Nnb3n1/1pkpQp1r/p1p5/8/8/8/P1P1PPPP/RNB1KBNR

> > SPG 9.5

> 

> You're right, as shown below :

> 

> 1.Pc2-c3   Pb7-b5   2.Dd1-a4   Pb5-b4   3.Da4xa7   Pb4-b3

> 4.Da7-e3   Ta8-a5   5.Pa2-a4   Fc8-a6   6.Ta1-a2   Pb3xa2

> 7.Re1-d1   Fa6xe2   8.Rd1-c2   Pa2-a1=C

> 

> The goal of my previous mails was only to indicate some solutions

> where

> Hiro's list was empty. Of course, the main point is now to find the

> shorter one in each category. I think that the above 8.0 is difficult

> to

> beat...

> 

> Nicolas.