Larry Smith wrote on Sun, Sep 17, 2006 08:15 PM UTC:
From what I can figure, it appears that the 4x4 field is tied to the 8x8
field by its single cell to a 2x2 group on the latter. So that the a1 cell
on the 4x4 field is tied to the a1, a2, b1, and b2 cells of the 8x8 field.
So a piece on the a1 cell of the 4x4 field would be able to move to an
empty cell on either a1, a2, b1 or b2 of the 8x8 field; and a piece on a1,
a2, b1 or b2 of the 8x8 field is able to move to an empty cell on a1 of the
4x4 field. This is why a bishop is able to break its diagonal pattern.
The wording of the rules is a little hazy. Would not pawn promotion be
allowed only on the 8x8 field?