diff --git a/src/board/chess_board/builder.rs b/src/board/chess_board/builder.rs
index d16c881..0304af5 100644
--- a/src/board/chess_board/builder.rs
+++ b/src/board/chess_board/builder.rs
@@ -1,4 +1,4 @@
-use crate::board::{Bitboard, CastleRights, ChessBoard, Color, InvalidError, Piece, Square};
+use crate::board::{Bitboard, CastleRights, ChessBoard, Color, Piece, Square, ValidationError};
 
 /// Build a [ChessBoard] one piece at a time.
 #[derive(Clone, Debug, PartialEq, Eq, PartialOrd, Ord)]
@@ -80,7 +80,7 @@ impl std::ops::IndexMut<Square> for ChessBoardBuilder {
 }
 
 impl TryFrom<ChessBoardBuilder> for ChessBoard {
-    type Error = InvalidError;
+    type Error = ValidationError;
 
     fn try_from(builder: ChessBoardBuilder) -> Result<Self, Self::Error> {
         let mut piece_occupancy: [Bitboard; Piece::NUM_VARIANTS] = Default::default();
diff --git a/src/board/chess_board/error.rs b/src/board/chess_board/error.rs
index 7b570a4..fe8e4c0 100644
--- a/src/board/chess_board/error.rs
+++ b/src/board/chess_board/error.rs
@@ -1,6 +1,6 @@
 /// A singular type for all errors that could happen during [ChessBoard::is_valid].
 #[derive(Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
-pub enum InvalidError {
+pub enum ValidationError {
     /// Too many pieces.
     TooManyPieces,
     /// Missing king.
@@ -27,7 +27,7 @@ pub enum InvalidError {
     IncoherentPlieCount,
 }
 
-impl std::fmt::Display for InvalidError {
+impl std::fmt::Display for ValidationError {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         let error_msg = match self {
             Self::TooManyPieces => "Too many pieces.",
@@ -53,4 +53,4 @@ impl std::fmt::Display for InvalidError {
     }
 }
 
-impl std::error::Error for InvalidError {}
+impl std::error::Error for ValidationError {}
diff --git a/src/board/chess_board/mod.rs b/src/board/chess_board/mod.rs
index 7fc43af..edf92a2 100644
--- a/src/board/chess_board/mod.rs
+++ b/src/board/chess_board/mod.rs
@@ -206,16 +206,16 @@ impl ChessBoard {
         self.validate().is_ok()
     }
 
-    /// Validate the state of the board. Return Err([InvalidError]) if an issue is found.
-    pub fn validate(&self) -> Result<(), InvalidError> {
+    /// Validate the state of the board. Return Err([ValidationError]) if an issue is found.
+    pub fn validate(&self) -> Result<(), ValidationError> {
         // The current plie count should be odd on white's turn, and vice-versa.
         if self.total_plies() % 2 != self.current_player().index() as u32 {
-            return Err(InvalidError::IncoherentPlieCount);
+            return Err(ValidationError::IncoherentPlieCount);
         }
 
         // Make sure the clocks are in agreement.
         if self.half_move_clock() > self.total_plies() {
-            return Err(InvalidError::HalfMoveClockTooHigh);
+            return Err(ValidationError::HalfMoveClockTooHigh);
         }
 
         // Don't overlap pieces.
@@ -224,7 +224,7 @@ impl ChessBoard {
             for other in Piece::iter() {
                 if piece != other {
                     if !(self.piece_occupancy(piece) & self.piece_occupancy(other)).is_empty() {
-                        return Err(InvalidError::OverlappingPieces);
+                        return Err(ValidationError::OverlappingPieces);
                     }
                 }
             }
@@ -232,7 +232,7 @@ impl ChessBoard {
 
         // Don't overlap colors.
         if !(self.color_occupancy(Color::White) & self.color_occupancy(Color::Black)).is_empty() {
-            return Err(InvalidError::OverlappingColors);
+            return Err(ValidationError::OverlappingColors);
         }
 
         // Calculate the union of all pieces.
@@ -241,12 +241,12 @@ impl ChessBoard {
 
         // Ensure that the pre-computed version is accurate.
         if combined != self.combined_occupancy() {
-            return Err(InvalidError::ErroneousCombinedOccupancy);
+            return Err(ValidationError::ErroneousCombinedOccupancy);
         }
 
         // Ensure that all pieces belong to a color, and no color has pieces that don't exist.
         if combined != (self.color_occupancy(Color::White) | self.color_occupancy(Color::Black)) {
-            return Err(InvalidError::ErroneousCombinedOccupancy);
+            return Err(ValidationError::ErroneousCombinedOccupancy);
         }
 
         for color in Color::iter() {
@@ -260,18 +260,18 @@ impl ChessBoard {
                     _ => count <= 10,
                 };
                 if !possible {
-                    return Err(InvalidError::TooManyPieces);
+                    return Err(ValidationError::TooManyPieces);
                 }
             }
 
             // Check that we have a king
             if self.occupancy(Piece::King, color).count() != 1 {
-                return Err(InvalidError::MissingKing);
+                return Err(ValidationError::MissingKing);
             }
 
             // Check that don't have too many pieces in total
             if self.color_occupancy(color).count() > 16 {
-                return Err(InvalidError::TooManyPieces);
+                return Err(ValidationError::TooManyPieces);
             }
         }
 
@@ -280,7 +280,7 @@ impl ChessBoard {
             & (Rank::First.into_bitboard() | Rank::Eighth.into_bitboard()))
         .is_empty()
         {
-            return Err(InvalidError::InvalidPawnPosition);
+            return Err(ValidationError::InvalidPawnPosition);
         }
 
         // Verify that rooks and kings that are allowed to castle have not been moved.
@@ -296,14 +296,14 @@ impl ChessBoard {
             let expected_rooks = castle_rights.unmoved_rooks(color);
             // We must check the intersection, in case there are more than 2 rooks on the board.
             if (expected_rooks & actual_rooks) != expected_rooks {
-                return Err(InvalidError::InvalidCastlingRights);
+                return Err(ValidationError::InvalidCastlingRights);
             }
 
             let actual_king = self.occupancy(Piece::King, color);
             let expected_king = Square::new(File::E, color.first_rank());
             // We have checked that there is exactly one king, no need for intersecting the sets.
             if actual_king != expected_king.into_bitboard() {
-                return Err(InvalidError::InvalidCastlingRights);
+                return Err(ValidationError::InvalidCastlingRights);
             }
         }
 
@@ -311,14 +311,14 @@ impl ChessBoard {
         if let Some(square) = self.en_passant() {
             // Must be empty
             if !(self.combined_occupancy() & square).is_empty() {
-                return Err(InvalidError::InvalidEnPassant);
+                return Err(ValidationError::InvalidEnPassant);
             }
 
             let opponent = !self.current_player();
 
             // Must be on the opponent's third rank
             if (square & opponent.third_rank().into_bitboard()).is_empty() {
-                return Err(InvalidError::InvalidEnPassant);
+                return Err(ValidationError::InvalidEnPassant);
             }
 
             // Must be behind a pawn
@@ -328,7 +328,7 @@ impl ChessBoard {
                 .backward_direction()
                 .move_board(square.into_bitboard());
             if (opponent_pawns & double_pushed_pawn).is_empty() {
-                return Err(InvalidError::InvalidEnPassant);
+                return Err(ValidationError::InvalidEnPassant);
             }
         }
 
@@ -337,12 +337,12 @@ impl ChessBoard {
         let black_king = self.occupancy(Piece::King, Color::Black);
         // Unwrap is fine, we already checked that there is exactly one king of each color
         if !(movegen::king_moves(white_king.try_into().unwrap()) & black_king).is_empty() {
-            return Err(InvalidError::NeighbouringKings);
+            return Err(ValidationError::NeighbouringKings);
         }
 
         // Check that the opponent is not currently in check.
         if !self.compute_checkers(!self.current_player()).is_empty() {
-            return Err(InvalidError::OpponentInCheck);
+            return Err(ValidationError::OpponentInCheck);
         }
 
         Ok(())
@@ -445,7 +445,7 @@ mod test {
         };
         assert_eq!(
             position.validate().err().unwrap(),
-            InvalidError::IncoherentPlieCount,
+            ValidationError::IncoherentPlieCount,
         );
     }
 
@@ -458,7 +458,7 @@ mod test {
             builder.with_half_move_clock(10);
             TryInto::<ChessBoard>::try_into(builder)
         };
-        assert_eq!(res.err().unwrap(), InvalidError::HalfMoveClockTooHigh);
+        assert_eq!(res.err().unwrap(), ValidationError::HalfMoveClockTooHigh);
     }
 
     #[test]
@@ -473,7 +473,7 @@ mod test {
         };
         assert_eq!(
             position.validate().err().unwrap(),
-            InvalidError::OverlappingPieces,
+            ValidationError::OverlappingPieces,
         );
     }
 
@@ -489,7 +489,7 @@ mod test {
         };
         assert_eq!(
             position.validate().err().unwrap(),
-            InvalidError::OverlappingColors,
+            ValidationError::OverlappingColors,
         );
     }
 
@@ -505,7 +505,7 @@ mod test {
         };
         assert_eq!(
             position.validate().err().unwrap(),
-            InvalidError::ErroneousCombinedOccupancy,
+            ValidationError::ErroneousCombinedOccupancy,
         );
     }
 
@@ -521,7 +521,7 @@ mod test {
         };
         assert_eq!(
             position.validate().err().unwrap(),
-            InvalidError::ErroneousCombinedOccupancy,
+            ValidationError::ErroneousCombinedOccupancy,
         );
     }
 
@@ -535,7 +535,7 @@ mod test {
             builder[Square::E8] = Some((Piece::King, Color::Black));
             TryInto::<ChessBoard>::try_into(builder)
         };
-        assert_eq!(res.err().unwrap(), InvalidError::TooManyPieces);
+        assert_eq!(res.err().unwrap(), ValidationError::TooManyPieces);
     }
 
     #[test]
@@ -547,7 +547,7 @@ mod test {
             builder.with_castle_rights(CastleRights::BothSides, Color::White);
             TryInto::<ChessBoard>::try_into(builder)
         };
-        assert_eq!(res.err().unwrap(), InvalidError::InvalidCastlingRights);
+        assert_eq!(res.err().unwrap(), ValidationError::InvalidCastlingRights);
     }
 
     #[test]
@@ -563,7 +563,7 @@ mod test {
             builder.with_castle_rights(CastleRights::BothSides, Color::White);
             TryInto::<ChessBoard>::try_into(builder)
         };
-        assert_eq!(res.err().unwrap(), InvalidError::InvalidCastlingRights);
+        assert_eq!(res.err().unwrap(), ValidationError::InvalidCastlingRights);
     }
 
     #[test]
@@ -587,7 +587,7 @@ mod test {
             builder.with_en_passant(Square::A6);
             TryInto::<ChessBoard>::try_into(builder)
         };
-        assert_eq!(res.err().unwrap(), InvalidError::InvalidEnPassant);
+        assert_eq!(res.err().unwrap(), ValidationError::InvalidEnPassant);
     }
 
     #[test]
@@ -600,7 +600,7 @@ mod test {
             builder.with_en_passant(Square::A6);
             TryInto::<ChessBoard>::try_into(builder)
         };
-        assert_eq!(res.err().unwrap(), InvalidError::InvalidEnPassant);
+        assert_eq!(res.err().unwrap(), ValidationError::InvalidEnPassant);
     }
 
     #[test]
@@ -613,7 +613,7 @@ mod test {
             builder.with_en_passant(Square::A5);
             TryInto::<ChessBoard>::try_into(builder)
         };
-        assert_eq!(res.err().unwrap(), InvalidError::InvalidEnPassant);
+        assert_eq!(res.err().unwrap(), ValidationError::InvalidEnPassant);
     }
 
     #[test]
@@ -624,7 +624,7 @@ mod test {
             builder[Square::E2] = Some((Piece::King, Color::Black));
             TryInto::<ChessBoard>::try_into(builder)
         };
-        assert_eq!(res.err().unwrap(), InvalidError::NeighbouringKings);
+        assert_eq!(res.err().unwrap(), ValidationError::NeighbouringKings);
     }
 
     #[test]
@@ -636,7 +636,7 @@ mod test {
             builder[Square::E8] = Some((Piece::King, Color::Black));
             TryInto::<ChessBoard>::try_into(builder)
         };
-        assert_eq!(res.err().unwrap(), InvalidError::OpponentInCheck);
+        assert_eq!(res.err().unwrap(), ValidationError::OpponentInCheck);
     }
 
     #[test]
@@ -648,7 +648,7 @@ mod test {
             builder[Square::H8] = Some((Piece::King, Color::Black));
             TryInto::<ChessBoard>::try_into(builder)
         };
-        assert_eq!(res.err().unwrap(), InvalidError::InvalidPawnPosition);
+        assert_eq!(res.err().unwrap(), ValidationError::InvalidPawnPosition);
     }
 
     #[test]
@@ -665,7 +665,7 @@ mod test {
             }
             TryInto::<ChessBoard>::try_into(builder)
         };
-        assert_eq!(res.err().unwrap(), InvalidError::TooManyPieces);
+        assert_eq!(res.err().unwrap(), ValidationError::TooManyPieces);
     }
 
     #[test]
diff --git a/src/fen.rs b/src/fen.rs
index 90f6dd1..41a0696 100644
--- a/src/fen.rs
+++ b/src/fen.rs
@@ -1,5 +1,5 @@
 use crate::board::{
-    CastleRights, ChessBoard, ChessBoardBuilder, Color, File, InvalidError, Piece, Rank, Square,
+    CastleRights, ChessBoard, ChessBoardBuilder, Color, File, Piece, Rank, Square, ValidationError,
 };
 
 /// A trait to mark items that can be converted from a FEN input.
@@ -15,7 +15,7 @@ pub enum FenError {
     /// Invalid FEN input.
     InvalidFen,
     /// Invalid chess position.
-    InvalidPosition(InvalidError),
+    InvalidPosition(ValidationError),
 }
 
 impl std::fmt::Display for FenError {
@@ -29,9 +29,9 @@ impl std::fmt::Display for FenError {
 
 impl std::error::Error for FenError {}
 
-/// Allow converting a [InvalidError] into [FenError], for use with the '?' operator.
-impl From<InvalidError> for FenError {
-    fn from(err: InvalidError) -> Self {
+/// Allow converting a [ValidationError] into [FenError], for use with the '?' operator.
+impl From<ValidationError> for FenError {
+    fn from(err: ValidationError) -> Self {
         Self::InvalidPosition(err)
     }
 }