+constexpr Bitboard Rank1BB = 0xFF;
+constexpr Bitboard Rank2BB = Rank1BB << (8 * 1);
+constexpr Bitboard Rank3BB = Rank1BB << (8 * 2);
+constexpr Bitboard Rank4BB = Rank1BB << (8 * 3);
+constexpr Bitboard Rank5BB = Rank1BB << (8 * 4);
+constexpr Bitboard Rank6BB = Rank1BB << (8 * 5);
+constexpr Bitboard Rank7BB = Rank1BB << (8 * 6);
+constexpr Bitboard Rank8BB = Rank1BB << (8 * 7);