Significance
Narak Chaturdashi, also called Choti Diwali or Roop Chaudas, marks Lord Krishna's slaying of the demon Narakasura and the freeing of 16,000 captives. It is the second day of the Diwali festival.
An early-morning ritual bath is believed to cleanse sins and bestow beauty (roop), hence Roop Chaudas.
Rituals
Devotees rise before dawn for the abhyanga snan — a ceremonial oil bath — light lamps, and offer to Yama. Homes glow with diyas on the eve of the main Lakshmi Puja. In some regions it is merged with the main Diwali night.
How the date is fixed
Narak Chaturdashi falls on the Chaturdashi of Kartika Krishna paksha, the day before Diwali; the abhyanga snan is done in the pre-dawn.