diff --git a/modules/core/src/main/scala/de/nowchess/chess/notation/PgnParser.scala b/modules/core/src/main/scala/de/nowchess/chess/notation/PgnParser.scala
index 214a396..a362daf 100644
--- a/modules/core/src/main/scala/de/nowchess/chess/notation/PgnParser.scala
+++ b/modules/core/src/main/scala/de/nowchess/chess/notation/PgnParser.scala
@@ -43,11 +43,9 @@ object PgnParser:
           parseAlgebraicMove(token, board, history, color) match
             case None => state  // unrecognised token — skip silently
             case Some(move) =>
-              val newBoard =
-                if move.castleSide.isDefined then
-                  board.withCastle(color, move.castleSide.get)
-                else
-                  board.withMove(move.from, move.to)._1
+              val newBoard = move.castleSide match
+                case Some(side) => board.withCastle(color, side)
+                case None       => board.withMove(move.from, move.to)._1
               val newHistory = history.addMove(move)
               (newBoard, newHistory, color.opposite, acc :+ move)