[Retros] Alsatian Einstein

[Joost de Heer]

There's a small article by Bernd Gräfrath in feenschach 204 about 
Alsatian chess (every position must be orthodox legal) in combination 
with other fairy conditions like Einstein or Losing chess.

How are checks treated in Alsatian chess? Are they orthodox or should 
the position after the capture of the king be orthodox 'legal'?

E.g. after 1. e3 e6 2. e4 Ke7 3. e5, is 3... Kd6 legal in Alsatian 
Einstein, because 4. exd6=S results in a knight which could never have 
been realised in orthodox chess?

Joost