-extern Bitboard BMasks[SQUARE_NB];
-extern Bitboard BMagics[SQUARE_NB];
-extern Bitboard* BAttacks[SQUARE_NB];
-extern unsigned BShifts[SQUARE_NB];
+const Bitboard Rank1BB = 0xFF;
+const Bitboard Rank2BB = Rank1BB << (8 * 1);
+const Bitboard Rank3BB = Rank1BB << (8 * 2);
+const Bitboard Rank4BB = Rank1BB << (8 * 3);
+const Bitboard Rank5BB = Rank1BB << (8 * 4);
+const Bitboard Rank6BB = Rank1BB << (8 * 5);
+const Bitboard Rank7BB = Rank1BB << (8 * 6);
+const Bitboard Rank8BB = Rank1BB << (8 * 7);
+
+extern int SquareDistance[SQUARE_NB][SQUARE_NB];