- NO_PIECE = 0, WP = 1, WN = 2, WB = 3, WR = 4, WQ = 5, WK = 6,
- BP = 9, BN = 10, BB = 11, BR = 12, BQ = 13, BK = 14,
- EMPTY = 16, OUTSIDE = 17
+ NO_PIECE_DARK_SQ = 0, WP = 1, WN = 2, WB = 3, WR = 4, WQ = 5, WK = 6,
+ BP = 9, BN = 10, BB = 11, BR = 12, BQ = 13, BK = 14, NO_PIECE = 16