diff --git a/moves/Cargo.toml b/moves/Cargo.toml
index b042344..797f7c8 100644
--- a/moves/Cargo.toml
+++ b/moves/Cargo.toml
@@ -9,3 +9,4 @@ edition = "2021"
 chessfriend_bitboard = { path = "../bitboard" }
 chessfriend_board = { path = "../board" }
 chessfriend_core = { path = "../core" }
+thiserror = "2"
diff --git a/moves/src/defs.rs b/moves/src/defs.rs
index 8254cb9..caea420 100644
--- a/moves/src/defs.rs
+++ b/moves/src/defs.rs
@@ -2,8 +2,9 @@
 
 use chessfriend_core::Shape;
 
+#[repr(u16)]
 #[derive(Clone, Copy, Debug, Eq, PartialEq)]
-pub(crate) enum Kind {
+pub enum Kind {
     Quiet = 0b0000,
     DoublePush = 0b0001,
     KingSideCastle = 0b0010,
@@ -14,12 +15,6 @@ pub(crate) enum Kind {
     CapturePromotion = 0b1100,
 }
 
-impl Kind {
-    fn is_reversible(self) -> bool {
-        (self as u16) & 0b1100 == 0
-    }
-}
-
 #[repr(u16)]
 #[derive(Copy, Clone, Debug, Eq, PartialEq)]
 pub enum PromotionShape {
diff --git a/moves/src/lib.rs b/moves/src/lib.rs
index e43a61d..09ccb0d 100644
--- a/moves/src/lib.rs
+++ b/moves/src/lib.rs
@@ -7,5 +7,5 @@ mod defs;
 mod moves;
 
 pub use builder::{Builder, Error as BuildMoveError, Result as BuildMoveResult};
-pub use defs::PromotionShape;
+pub use defs::{Kind, PromotionShape};
 pub use moves::Move;
diff --git a/moves/src/moves.rs b/moves/src/moves.rs
index b7d2539..bc66d77 100644
--- a/moves/src/moves.rs
+++ b/moves/src/moves.rs
@@ -1,5 +1,6 @@
 // Eryn Wells <eryn@erynwells.me>
 
+use crate::builder::Builder;
 use crate::defs::Kind;
 use chessfriend_board::castle::Castle;
 use chessfriend_core::{Rank, Shape, Square};
@@ -57,7 +58,7 @@ impl Move {
 
     #[must_use]
     pub fn is_castle(&self) -> bool {
-        self.castle().is_some()
+        (self.0 & 0b0010) != 0
     }
 
     #[must_use]
@@ -71,17 +72,17 @@ impl Move {
 
     #[must_use]
     pub fn is_capture(&self) -> bool {
-        (self.0 & 0b0100) != 0
+        (self.0 & Kind::Capture as u16) != 0
     }
 
     #[must_use]
     pub fn is_en_passant(&self) -> bool {
-        self.flags() == 0b0101
+        self.0 == Kind::EnPassantCapture as u16
     }
 
     #[must_use]
     pub fn is_promotion(&self) -> bool {
-        (self.0 & 0b1000) != 0
+        (self.0 & Kind::Promotion as u16) != 0
     }
 
     #[must_use]
@@ -113,7 +114,7 @@ impl Move {
 }
 
 impl Move {
-    fn _transfer_char(self) -> char {
+    fn transfer_char(self) -> char {
         if self.is_capture() || self.is_en_passant() {
             'x'
         } else {
@@ -122,18 +123,21 @@ impl Move {
     }
 }
 
+const KINGSIDE_CASTLE_STR: &str = "0-0";
+const QUEENSIDE_CASTLE_STR: &str = "0-0-0";
+
 impl fmt::Display for Move {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         if let Some(castle) = self.castle() {
             return match castle {
-                Castle::KingSide => write!(f, "0-0"),
-                Castle::QueenSide => write!(f, "0-0-0"),
+                Castle::KingSide => write!(f, "{KINGSIDE_CASTLE_STR}"),
+                Castle::QueenSide => write!(f, "{QUEENSIDE_CASTLE_STR}"),
             };
         }
 
         let origin = self.origin_square();
         let target = self.target_square();
-        let transfer_char = self._transfer_char();
+        let transfer_char = self.transfer_char();
         write!(f, "{origin}{transfer_char}{target}")?;
 
         if let Some(promotion) = self.promotion() {