diff --git a/exercises/practice/state-of-tic-tac-toe/.meta/Example.cs b/exercises/practice/state-of-tic-tac-toe/.meta/Example.cs
index 782932767..b651699bb 100644
--- a/exercises/practice/state-of-tic-tac-toe/.meta/Example.cs
+++ b/exercises/practice/state-of-tic-tac-toe/.meta/Example.cs
@@ -14,6 +14,8 @@ public State State
         {   
             if (Moves.GetValueOrDefault('X', 0) - Moves.GetValueOrDefault('O', 0) > 1 ||
                 Moves.GetValueOrDefault('O', 0) > Moves.GetValueOrDefault('X', 0) ||
+                Winners.Contains('X') && Moves.GetValueOrDefault('X', 0) == Moves.GetValueOrDefault('O', 0) ||
+                Winners.Contains('O') && Moves.GetValueOrDefault('X', 0) > Moves.GetValueOrDefault('O', 0) ||
                 Winners.Distinct().Count() > 1)
                 return State.Invalid;
 
diff --git a/exercises/practice/state-of-tic-tac-toe/.meta/tests.toml b/exercises/practice/state-of-tic-tac-toe/.meta/tests.toml
index 8fc25e211..5f574b2a1 100644
--- a/exercises/practice/state-of-tic-tac-toe/.meta/tests.toml
+++ b/exercises/practice/state-of-tic-tac-toe/.meta/tests.toml
@@ -99,3 +99,9 @@ reimplements = "b1dc8b13-46c4-47db-a96d-aa90eedc4e8d"
 
 [4801cda2-f5b7-4c36-8317-3cdd167ac22c]
 description = "Invalid boards -> Invalid board: players kept playing after a win"
+
+[5a84757a-fc86-4328-aec9-a5759e6ed35d]
+description = "Invalid boards -> Invalid board: O kept playing after X wins"
+
+[cf25543d-583a-4656-b9ab-f82dc00a4a02]
+description = "Invalid boards -> Invalid board: X kept playing after O wins"
diff --git a/exercises/practice/state-of-tic-tac-toe/StateOfTicTacToeTests.cs b/exercises/practice/state-of-tic-tac-toe/StateOfTicTacToeTests.cs
index 0c278a709..96c5fda90 100644
--- a/exercises/practice/state-of-tic-tac-toe/StateOfTicTacToeTests.cs
+++ b/exercises/practice/state-of-tic-tac-toe/StateOfTicTacToeTests.cs
@@ -323,4 +323,28 @@ public void Invalid_boards_invalid_board_players_kept_playing_after_a_win()
         var game = new TicTacToe(board);
         Assert.Equal(State.Invalid, game.State);
     }
+
+    [Fact(Skip = "Remove this Skip property to run this test")]
+    public void Invalid_boards_invalid_board_o_kept_playing_after_x_wins()
+    {
+        string[] board = [
+            "OO ",
+            "XXX",
+            " O "
+        ];
+        var game = new TicTacToe(board);
+        Assert.Equal(State.Invalid, game.State);
+    }
+
+    [Fact(Skip = "Remove this Skip property to run this test")]
+    public void Invalid_boards_invalid_board_x_kept_playing_after_o_wins()
+    {
+        string[] board = [
+            "XX ",
+            "OOO",
+            " XX"
+        ];
+        var game = new TicTacToe(board);
+        Assert.Equal(State.Invalid, game.State);
+    }
 }