diff --git a/src/repr/bitboard.rs b/src/repr/bitboard.rs
index 4a922f1..dda636e 100644
--- a/src/repr/bitboard.rs
+++ b/src/repr/bitboard.rs
@@ -44,34 +44,34 @@ impl BitBoard {
 
     #[const_fn(cfg(not(feature = "bitvec")))]
     pub const fn get(&self, row: Coord, col: Coord) -> bool {
-        self.get_by_index(get_index(row, col) as usize)
+        self.get_by_index(get_index(row, col))
     }
 
     #[const_fn(cfg(not(feature = "bitvec")))]
     pub const fn set(&mut self, row: Coord, col: Coord, value: bool) {
-        self.set_by_index(get_index(row, col) as usize, value);
+        self.set_by_index(get_index(row, col), value);
     }
 
     #[cfg(not(feature = "bitvec"))]
-    const fn get_by_index(&self, index: usize) -> bool {
+    const fn get_by_index(&self, index: Coord) -> bool {
         ((self.0 >> index) & 0b1) != 0b0
     }
 
     #[cfg(not(feature = "bitvec"))]
-    const fn set_by_index(&mut self, index: usize, value: bool) {
+    const fn set_by_index(&mut self, index: Coord, value: bool) {
         // PERF! branchless setting of bit (~+3% perf bump)
         self.0 &= !(0b1 << index); // clear bit
         self.0 |= (value as BitBoardInner) << index; // set bit (if needed)
     }
 
     #[cfg(feature = "bitvec")]
-    pub fn get_by_index(&self, index: usize) -> bool {
-        self.0[index]
+    pub fn get_by_index(&self, index: Coord) -> bool {
+        self.0[index as usize]
     }
 
     #[cfg(feature = "bitvec")]
-    pub fn set_by_index(&mut self, index: usize, value: bool) {
-        self.0.set(index, value);
+    pub fn set_by_index(&mut self, index: Coord, value: bool) {
+        self.0.set(index as usize, value);
     }
 
     // works on both `bitvec` and native (const on native)