[Retros] forced h#2 in retroplay.

[Olli Heimo]

There is a helpmate in two in the initial game array. But the
position is illegal, because it is White to move. I just
wonder how long can be a game, where at no instance a
helpmate in two is possible. White must begin with 1.Nf3 or
1.f3 or 1.g4. Then it seems to me that very long games are
possible. Does any of those games end with a real beautiful
helpmate problem. Nice challenge, I think. Olli.