diff --git a/src/board.rs b/src/board.rs
index ab258a5..5955689 100644
--- a/src/board.rs
+++ b/src/board.rs
@@ -39,9 +39,6 @@ pub const fn get_type(square: u8) -> u8 { square & SQ_TYPE_MASK }
 /// Return true if the piece on this square is of type `piece_type`.
 #[inline]
 pub const fn is_type(square: u8, piece_type: u8) -> bool { get_type(square) == piece_type }
-/// Return true if the piece on this square is the same as `piece`.
-#[inline]
-pub const fn is_piece(square: u8, piece: u8) -> bool { has_flag(square, piece) }
 /// Return true if the piece on this square has this color.
 #[inline]
 pub const fn is_color(square: u8, color: u8) -> bool { has_flag(square, color) }
@@ -54,6 +51,9 @@ pub const fn is_black(square: u8) -> bool { is_color(square, SQ_BL) }
 /// Return the color of the piece on this square.
 #[inline]
 pub const fn get_color(square: u8) -> u8 { square & SQ_COLOR_MASK }
+/// Return true if the piece on this square is the same as `piece`.
+#[inline]
+pub const fn is_piece(square: u8, piece: u8) -> bool { has_flag(square, piece) }
 
 /// Get opposite color.
 #[inline]
diff --git a/src/rules.rs b/src/rules.rs
index 64a03e8..3474c32 100644
--- a/src/rules.rs
+++ b/src/rules.rs
@@ -72,7 +72,7 @@ pub fn apply_move_to(board: &mut Board, game_state: &mut GameState, m: &Move) {
             _ => {}
         };
     }
-    // Else, check if it's either to rook or the king that moved.
+    // Else, check if it's either a rook or the king that moved.
     else {
         let piece = get_square(board, &m.1);
         if is_white(piece) && game_state.castling & CASTLING_WH_MASK != 0 {
@@ -135,6 +135,10 @@ pub fn apply_move_to_board(board: &mut Board, m: &Move) {
         }
     } else {
         move_piece(board, &m.0, &m.1);
+        if let Some(prom_type) = m.2 {
+            let color = get_color(get_square(board, &m.1));
+            set_square(board, &m.1, color|prom_type);
+        }
     }
 }