[Retros] Promotion: legal order of partial actions

[Mario Richter]

Valery Liskovets wrote:


> In general, it is sometimes difficult to comprehend

> such problems without knowing author's intention

> and/or getting his additional comments.


At least for XI and XII I had included a comment made
by Finzer (s. point 4. at the beginning of my mail).

I didn't include the solutions, because I wanted to give
potential readers the chance to analyze (and solve) the
problems themselves first.

XI: 
The position is obviously illegal: 8 white pawns together
with 2 dark-squared white bishops is impossible.

Now the stipulation "White completes his last move" gives
you the necessary information to explain this illegality:
White is in the process of promoting a pawn, and has already
placed the new born bishop on the promotion square.
He now completes his move by removing the promoting pawn.
As you correctly mentioned, it cannot be detected if 
Pe7xd8=B or Pg7xh8=B is White's last move, so we have
some kind of pRA here.


> The former contains bP on c7.

I do not understand this comment - the position as given
is identical to that in "Die Schwalbe" (i.e. black bishop on c7).


XII:
White pawns have captured 13 times, but only 12 black men
are missing.
So if White wants to move, first Black has to complete 
his last move Ph2-h1=R by removing the bPh2.
If Black wants to move, first White has to complete 
his last move Pd5xe6 e.p.


Regards,

  mario