1. The description doesn't make it clear that the center of a piece can be
on one of the side rows (a, t, 1, 20). This means that Black may start the
game with the move a3-b3. See
http://www.archim.org.uk/eureka/53/gess.html.
2. I don't know if it is allowed to move the center of a piece onto a
side row. Is black allowed to start a game with r3-t3, capturing four of
his stones? Or can a piece move only so far as to move the direction stone
onto a side row?