updated 090322
RC1: CLARIFICATION: Maskirovka card:
SOURCE: Carl Paradis (Designer)
Date: 090322
Consider that a "friendly" hex in this case is any hex, supplied, that a unit could have regularly moved into (give unlimited movement points to the unit), obeying all the movement rules, from one of your supply sources (the board edge or a city).
With your wording you would have been able to put a Soviet unit right in a hex on the frontline between two German units (a hex not reachable by Movement alone, but theorically in supply if adjacent to another Soviet unit). Which is what I wanted to avoid!
What about this:
Consider that a "friendly" hex in this case is any hex, OVERLAND SUPPLIED, that a unit could have regularly moved into (give unlimited movement points to the unit), obeying all the movement rules, from one of your supply sources (the board edge or a city).