diff --git a/runelite-client/src/main/java/net/runelite/client/plugins/runedoku/Sudoku.java b/runelite-client/src/main/java/net/runelite/client/plugins/runedoku/Sudoku.java
index 69a404ee4c..22656e5b47 100644
--- a/runelite-client/src/main/java/net/runelite/client/plugins/runedoku/Sudoku.java
+++ b/runelite-client/src/main/java/net/runelite/client/plugins/runedoku/Sudoku.java
@@ -8,7 +8,7 @@ package net.runelite.client.plugins.runedoku;
 class Sudoku
 {
 
-	private int[][] board;
+	private final int[][] board;
 	private static final int EMPTY = 0;
 	private static final int SIZE = 9;