diff --git a/go/marshaling_test.go b/go/marshaling_test.go
index 0b2209e..56222e5 100644
--- a/go/marshaling_test.go
+++ b/go/marshaling_test.go
@@ -100,7 +100,7 @@ func TestMarshal(t *testing.T) {
 		GGG: []G{{ID: "1", AAA: "ggg"}},
 		HHH: []*G{{ID: "2", AAA: "hhh"}, nil},
 		JJJ: &Value{value: "foo"},
-		KKK: &Tag{ID: "tag"},
+		KKK: &Tag{Name: "tag"},
 	}
 
 	expected := &Item{
diff --git a/go/value.go b/go/value.go
index 953e214..80f58f3 100644
--- a/go/value.go
+++ b/go/value.go
@@ -73,6 +73,9 @@ func TagsFrom(j any) []Tag {
 }
 
 func (t Tag) MarshalCMS() any {
+	if t.ID == "" {
+		return t.Name
+	}
 	return t.ID
 }