+extern Bitboard SquareBB[64];
+extern Bitboard FileBB[8];
+extern Bitboard RankBB[8];
+extern Bitboard AdjacentFilesBB[8];
+extern Bitboard ThisAndAdjacentFilesBB[8];
+extern Bitboard InFrontBB[2][8];
+extern Bitboard StepAttacksBB[16][64];
+extern Bitboard BetweenBB[64][64];
+extern Bitboard SquaresInFrontMask[2][64];
+extern Bitboard PassedPawnMask[2][64];
+extern Bitboard AttackSpanMask[2][64];