Narayan Bali: Primarily focuses on liberating souls who died an unnatural death (Akal Mrityu) and are consequently stuck (Pret Yoni). It addresses the specific trauma and unfulfilled desires associated with such deaths.
Tripindi Shradh: Addresses ancestors (usually across three generations – father, grandfather, great-grandfather) whose regular Shraddha rites might have been neglected over time, or who are causing trouble due to strong lingering attachments (to food, clothes, wealth etc.). It aims to pacify these general ancestral dissatisfactions.
While both are performed at Pishach Mochan and aim for ancestral peace, Narayan Bali targets the specific issue of unnatural death, whereas Tripindi Shradh addresses neglect or general restlessness across generations. Often, they might be performed together if both situations apply.