-extern Bitboard SquareBB[SQUARE_NB];
-extern Bitboard FileBB[FILE_NB];
-extern Bitboard RankBB[RANK_NB];
-extern Bitboard AdjacentFilesBB[FILE_NB];
-extern Bitboard ThisAndAdjacentFilesBB[FILE_NB];
-extern Bitboard InFrontBB[COLOR_NB][RANK_NB];
-extern Bitboard StepAttacksBB[PIECE_NB][SQUARE_NB];
-extern Bitboard BetweenBB[SQUARE_NB][SQUARE_NB];
-extern Bitboard DistanceRingsBB[SQUARE_NB][8];
-extern Bitboard ForwardBB[COLOR_NB][SQUARE_NB];
-extern Bitboard PassedPawnMask[COLOR_NB][SQUARE_NB];
-extern Bitboard AttackSpanMask[COLOR_NB][SQUARE_NB];
-extern Bitboard PseudoAttacks[PIECE_TYPE_NB][SQUARE_NB];
+constexpr Bitboard QueenSide = FileABB | FileBBB | FileCBB | FileDBB;
+constexpr Bitboard CenterFiles = FileCBB | FileDBB | FileEBB | FileFBB;
+constexpr Bitboard KingSide = FileEBB | FileFBB | FileGBB | FileHBB;
+constexpr Bitboard Center = (FileDBB | FileEBB) & (Rank4BB | Rank5BB);