diff --git a/src/position.cpp b/src/position.cpp
index 90847624..4e863764 100644
--- a/src/position.cpp
+++ b/src/position.cpp
@@ -1624,7 +1624,7 @@ bool Position::is_all_surrounded() const
 
 bool Position::is_star_square(Square s)
 {
-    if (rule->nTotalPiecesEachSide == 12) {
+    if (rule->hasObliqueLines == true) {
         return (s == 17 ||
                 s == 19 ||
                 s == 21 ||
diff --git a/src/ui/flutter/lib/mill/position.dart b/src/ui/flutter/lib/mill/position.dart
index c7fa23d9..e9e6d8d7 100644
--- a/src/ui/flutter/lib/mill/position.dart
+++ b/src/ui/flutter/lib/mill/position.dart
@@ -1448,7 +1448,7 @@ class Position {
   }
 
   bool isStarSquare(int s) {
-    if (rule.nTotalPiecesEachSide == 12) {
+    if (rule.hasObliqueLines == true) {
       return (s == 17 || s == 19 || s == 21 || s == 23);
     }