Krishna and Satyabhama slay Narakasura; an oil bath before dawn marks the day before Diwali

Narak Chaturdashi is kept on the Chaturdashi of the dark half of Kartika (Purnimanta), the day before or the morning of Diwali. It celebrates the killing of the demon king Narakasura of Pragjyotishpura, son of Bhudevi, who had conquered the three worlds, stolen Aditi's earrings, and imprisoned 16,100 princesses. Lord Krishna, with Satyabhama as his charioteer — herself an incarnation of Bhudevi — fought and killed him; in some versions Satyabhama herself strikes the final blow, since Narakasura could only die at his mother's hand. As he died, Narakasura asked that his death be celebrated with lights. Krishna returned at dawn and took an oil bath to cleanse himself, and so the central ritual is the abhyang snan: an oil and ubtan bath before sunrise while the moon and Chaturdashi prevail. Crushing a bitter karit fruit (a symbol of Narakasura) underfoot before the bath is a Maharashtrian custom. Taking this bath is believed to save one from going to hell (naraka). Yama tarpan and lighting fourteen lamps follow. In the South this bath is the start of Deepavali itself; in the North it is Chhoti Diwali or Roop Chaudas.

No fast is prescribed; it is a festive day.