[Retros] 9 white pawns, cont'd

[Mario Richter]

> Noam wrote:

> 

>> George Leathem

>> The Problemist FCS 821 05/1933

>> 8/3pPKPp/4N1N1/4PkP1/3P1p1P/3PRPRP/8/5Q2

>> #1



> On further thought, even after removing one of White's nine pawns

> the position is illegal WTM unless it's the e5 or g5 pawn that's removed

> (when Black could have just played 0...e5xf4 or g5xf4); perhaps that's

> what Mario R. was hinting at. 


Exactly!


> Removing Pe7 also results in an impossible pawn configuration


As well as the removal of Pe5,Pd4 or Pd3.
This may perhaps be neglected by the following argumentation:
The position is illegal. So before trying to solve the problem,
the illegality must be removed.
Since there are 9 white pawns, one of them is guilty for the illegality.
Since after removing the wPe7 the position is still illegal,
it cannot have been this pawn.

For the WTM illegalities: this might still be o.k., if "#1" is
interpreted as a "Mate in one" problem, but it doesn't work here
for e.g. -wPg7, since after 0. ... d7xe6! White has no mate.
On the other hand, it would work for -wPh3, since after 0. ... ~
White can mate by 1.Qf3#


> There's also a dual mate Qb1(d3) in the -Pd3 branch.  It seems that

> this is easily fixed by moving Re3,g3 to e1,g1, which also lets us

> eliminate the retro-illegality issue by moving wPf3 and bPf4 down to

> f2 and f3 -- again assuming that we can retract 0 e2xd3++ (or 0 g2xh3++)

> Kf5 without introducing too many pawn captures on any of the seven

> branches that keep Pd3 and Ph3 on the board.


Positions after -Pe7, -Pe5 -Pd4 (and also after -Pd3) are still illegal ...


Best,

  mario