diff --git a/src/bitboard.cpp b/src/bitboard.cpp
index 77f49ef6..105d201f 100644
--- a/src/bitboard.cpp
+++ b/src/bitboard.cpp
@@ -24,7 +24,7 @@
 #include "misc.h"
 
 uint8_t PopCnt16[1 << 16];
-int SquareDistance[SQUARE_NB][SQUARE_NB];
+int8_t SquareDistance[SQUARE_NB][SQUARE_NB];
 
 Bitboard SquareBB[SQUARE_NB];
 Bitboard FileBB[FILE_NB];
diff --git a/src/bitboard.h b/src/bitboard.h
index e1c31dd7..b64c92e1 100644
--- a/src/bitboard.h
+++ b/src/bitboard.h
@@ -60,7 +60,7 @@ constexpr Bitboard Rank6BB = Rank1BB << (8 * 5);
 constexpr Bitboard Rank7BB = Rank1BB << (8 * 6);
 constexpr Bitboard Rank8BB = Rank1BB << (8 * 7);
 
-extern int SquareDistance[SQUARE_NB][SQUARE_NB];
+extern int8_t SquareDistance[SQUARE_NB][SQUARE_NB];
 
 extern Bitboard SquareBB[SQUARE_NB];
 extern Bitboard FileBB[FILE_NB];