Mochi and cooked rice were placed on the altars of deities as offerings in the evening of New Year's Eve, and they were taken down before dawn the next day and simmered with other ingredients to prepare a soup, which is believed to have been the origin of zoni.
大晦日の夕方に神仏に供えた餅や飯を日の出後に降ろして、具材を加えて煮た物が雑煮のルーツとされている。