diff --git a/board/src/position/position.rs b/board/src/position/position.rs
index 26ac3cf..cdaa62b 100644
--- a/board/src/position/position.rs
+++ b/board/src/position/position.rs
@@ -93,6 +93,17 @@ impl Position {
         Ok(())
     }
 
+    /// Return a BitBoard representing the set of squares containing a piece.
+    pub(crate) fn occupied_squares(&self) -> BitBoard {
+        self.pieces_per_color[Color::White as usize] | self.pieces_per_color[Color::Black as usize]
+    }
+
+    /// Return a BitBoard representing the set of squares containing a piece. This set is the inverse of `occupied_squares`.
+    pub(crate) fn empty_squares(&self) -> BitBoard {
+        !(self.pieces_per_color[Color::White as usize]
+            | self.pieces_per_color[Color::Black as usize])
+    }
+
     pub(crate) fn bitboard_for_piece(&self, piece: Piece) -> &BitBoard {
         &self.pieces_per_type[piece.color as usize][piece.shape as usize]
     }
@@ -101,11 +112,11 @@ impl Position {
         &mut self.pieces_per_type[piece.color as usize][piece.shape as usize]
     }
 
-    pub(self) fn bitboard_for_color(&self, color: Color) -> &BitBoard {
+    pub(crate) fn bitboard_for_color(&self, color: Color) -> &BitBoard {
         &self.pieces_per_color[color as usize]
     }
 
-    pub(self) fn bitboard_for_color_mut(&mut self, color: Color) -> &mut BitBoard {
+    fn bitboard_for_color_mut(&mut self, color: Color) -> &mut BitBoard {
         &mut self.pieces_per_color[color as usize]
     }