diff --git a/board/src/move_generator/bishop.rs b/board/src/move_generator/bishop.rs
index f4f7f9f..88f7631 100644
--- a/board/src/move_generator/bishop.rs
+++ b/board/src/move_generator/bishop.rs
@@ -48,7 +48,7 @@ impl<'pos> MoveGeneratorInternal for ClassicalMoveGenerator<'pos> {
         let quiet_moves_bb = all_moves & (empty_squares | !friendly_pieces);
         let capture_moves_bb = all_moves & opposing_pieces;
 
-        let map_to_move = |sq| MoveBuilder::new(piece, square, sq).build();
+        let map_to_move = |sq| MoveBuilder::new(*piece, square, sq).build();
         let quiet_moves = quiet_moves_bb.occupied_squares().map(map_to_move);
         let capture_moves = capture_moves_bb.occupied_squares().map(map_to_move);
 
diff --git a/board/src/move_generator/king.rs b/board/src/move_generator/king.rs
index b3500fd..06ae76e 100644
--- a/board/src/move_generator/king.rs
+++ b/board/src/move_generator/king.rs
@@ -56,7 +56,7 @@ impl<'pos> MoveGeneratorInternal for KingMoveGenerator<'pos> {
         // TODO: Handle checks. Prevent moving a king to a square attacked by a
         // piece of the opposite color.
 
-        let map_to_move = |sq| MoveBuilder::new(piece, square, sq).build();
+        let map_to_move = |sq| MoveBuilder::new(*piece, square, sq).build();
 
         let king_side_castle = Self::king_side_castle(position, color);
         let queen_side_castle = Self::queen_side_castle(position, color);
diff --git a/board/src/move_generator/knight.rs b/board/src/move_generator/knight.rs
index 3116b1e..50a7ad0 100644
--- a/board/src/move_generator/knight.rs
+++ b/board/src/move_generator/knight.rs
@@ -22,11 +22,11 @@ impl<'pos> MoveGeneratorInternal for KnightMoveGenerator<'pos> {
         let capture_moves_bb = knight_moves & opposing_pieces;
 
         let quiet_moves = quiet_moves_bb.occupied_squares().map(|to_sq| {
-            MoveBuilder::new(placed_piece.piece(), placed_piece.square(), to_sq).build()
+            MoveBuilder::new(*placed_piece.piece(), placed_piece.square(), to_sq).build()
         });
         let capture_moves = capture_moves_bb.occupied_squares().map(|to_sq| {
             let captured_piece = position.piece_on_square(to_sq).unwrap();
-            MoveBuilder::new(placed_piece.piece(), placed_piece.square(), to_sq)
+            MoveBuilder::new(*placed_piece.piece(), placed_piece.square(), to_sq)
                 .capturing(captured_piece)
                 .build()
         });
diff --git a/board/src/move_generator/queen.rs b/board/src/move_generator/queen.rs
index e7d03b6..6694bf6 100644
--- a/board/src/move_generator/queen.rs
+++ b/board/src/move_generator/queen.rs
@@ -53,7 +53,7 @@ impl<'pos> MoveGeneratorInternal for ClassicalMoveGenerator<'pos> {
         let quiet_moves_bb = all_moves & (empty_squares | !friendly_pieces);
         let capture_moves_bb = all_moves & opposing_pieces;
 
-        let map_to_move = |sq| MoveBuilder::new(piece, square, sq).build();
+        let map_to_move = |sq| MoveBuilder::new(*piece, square, sq).build();
         let quiet_moves = quiet_moves_bb.occupied_squares().map(map_to_move);
         let capture_moves = capture_moves_bb.occupied_squares().map(map_to_move);
 
diff --git a/board/src/move_generator/rook.rs b/board/src/move_generator/rook.rs
index d82c22c..bd48711 100644
--- a/board/src/move_generator/rook.rs
+++ b/board/src/move_generator/rook.rs
@@ -49,7 +49,7 @@ impl<'pos> MoveGeneratorInternal for ClassicalMoveGenerator<'pos> {
         let quiet_moves_bb = all_moves & (empty_squares | !friendly_pieces);
         let capture_moves_bb = all_moves & opposing_pieces;
 
-        let map_to_move = |sq| MoveBuilder::new(piece, square, sq).build();
+        let map_to_move = |sq| MoveBuilder::new(*piece, square, sq).build();
         let quiet_moves = quiet_moves_bb.occupied_squares().map(map_to_move);
         let capture_moves = capture_moves_bb.occupied_squares().map(map_to_move);
 
diff --git a/board/src/piece.rs b/board/src/piece.rs
index 557f96a..fa8333d 100644
--- a/board/src/piece.rs
+++ b/board/src/piece.rs
@@ -244,8 +244,8 @@ impl PlacedPiece {
     }
 
     #[inline]
-    pub fn piece(&self) -> Piece {
-        self.piece
+    pub fn piece(&self) -> &Piece {
+        &self.piece
     }
 
     #[inline]
diff --git a/board/src/position/piece_sets.rs b/board/src/position/piece_sets.rs
index 2e97669..cd8f26d 100644
--- a/board/src/position/piece_sets.rs
+++ b/board/src/position/piece_sets.rs
@@ -66,11 +66,11 @@ impl PieceBitBoards {
         self.by_color.bitboard_mut(color)
     }
 
-    pub(super) fn bitboard_for_piece(&self, piece: Piece) -> &BitBoard {
+    pub(super) fn bitboard_for_piece(&self, piece: &Piece) -> &BitBoard {
         self.by_color_and_shape.bitboard_for_piece(piece)
     }
 
-    pub(super) fn bitboard_for_piece_mut(&mut self, piece: Piece) -> &mut BitBoard {
+    pub(super) fn bitboard_for_piece_mut(&mut self, piece: &Piece) -> &mut BitBoard {
         self.by_color_and_shape.bitboard_for_piece_mut(piece)
     }
 
@@ -135,15 +135,15 @@ impl ByColor {
 }
 
 impl ByColorAndShape {
-    fn bitboard_for_piece(&self, piece: Piece) -> &BitBoard {
+    fn bitboard_for_piece(&self, piece: &Piece) -> &BitBoard {
         &self.0[piece.color() as usize][piece.shape() as usize]
     }
 
-    fn bitboard_for_piece_mut(&mut self, piece: Piece) -> &mut BitBoard {
+    fn bitboard_for_piece_mut(&mut self, piece: &Piece) -> &mut BitBoard {
         &mut self.0[piece.color() as usize][piece.shape() as usize]
     }
 
-    fn set_square(&mut self, square: Square, piece: Piece) {
+    fn set_square(&mut self, square: Square, piece: &Piece) {
         self.bitboard_for_piece_mut(piece).set_square(square);
     }
 }
diff --git a/board/src/position/position.rs b/board/src/position/position.rs
index 2ee5564..1c2831d 100644
--- a/board/src/position/position.rs
+++ b/board/src/position/position.rs
@@ -144,7 +144,7 @@ impl Position {
         for color in Color::iter() {
             for shape in Shape::iter() {
                 let piece = Piece::new(color, *shape);
-                if self.pieces.bitboard_for_piece(piece).is_set(sq) {
+                if self.pieces.bitboard_for_piece(&piece).is_set(sq) {
                     return Some(PlacedPiece::new(piece, sq));
                 }
             }
@@ -176,7 +176,7 @@ impl Position {
 
     fn king_square(&self) -> Square {
         self.pieces
-            .bitboard_for_piece(Piece::king(self.color_to_move))
+            .bitboard_for_piece(&Piece::king(self.color_to_move))
             .occupied_squares()
             .next()
             .unwrap()
@@ -207,6 +207,10 @@ impl Position {
     pub(super) fn flags(&self) -> Flags {
         self.flags
     }
+
+    pub(super) fn piece_bitboards(&self) -> &PieceBitBoards {
+        &self.pieces
+    }
 }
 
 // crate methods
@@ -216,7 +220,7 @@ impl Position {
     }
 
     pub(crate) fn bitboard_for_piece(&self, piece: Piece) -> &BitBoard {
-        self.pieces.bitboard_for_piece(piece)
+        self.pieces.bitboard_for_piece(&piece)
     }
 }