Hrmmm...What defines which side is the black side and which side is white? Is it not the starting position? Since all normal cues are missing, something else must decide "Black's Pawn Movement Direction", etc. (I'm assuming there are no coordinates on the board, like there are in game discussions.)
So, given no hints, Black can "assume the position" at either end. Under normal chess rules this would determine the pawn direction, would it not?