a b c d e f g h
.
   8  r n b q k b n r  8
   7  = =   = = = = =  7
   6  .   =   .   .    6
   5    .   .   .   .  5
   4  .   .   #   .    4
   3    .   .   .   .  3
   2  # # # # . # # #  2
   1  R N B Q K B N R  1
#
      a b c d e f g h