Class IV, of those groups made up of eight valleys of greater area.
Groups of the first class always have an area of twenty points; those of
the second have an area of twenty-three points; those of the third have
an area of twenty-five points, and those of the fourth have an area of
twenty-seven points. Such areas always are exclusive of that point upon
which the Queen is posted.
Although impassable natural barriers restrict the movement of the Queen
to less than one-half of the Topographical Zone, these obstacles always
are intersected by long stretches of open country formed by intervening
valleys.
Hence, the march of this most mobile of the Chesspieces always is open
either in three, five, or eight directions, and it always is possible for
her, unless impeded by the interference of kindred or hostile corps, to
reach any desired point on the Chess-board in two moves.
The weakness peculiar to the Topographical Horizon which appertains to
the Queen, originates in the fact that it never commands the origins of
obliques. Consequently, every post of the Queen, is open to unopposed
attack by the hostile Knights.