
The nobles of the Imperial court believed that long strands of freshly made mochi symbolized long life and well-being, while dried mochi helped strengthen one's teeth. The first recorded accounts of mochi being used as a part of New Year's festivities are from the Heian period. : 30 In this period, it became customary in the aristocratic society for the bride and groom to eat mochi together at the bride's house three days after the wedding. According to the Ōkagami compiled in the 12th century, emperors and nobilities used to put mochi into the mouths of babies that were 50 days old. In the Heian period (794–1185), mochi was often used in Shinto events to celebrate childbirth and marriage. This legend shows that round white mochi was historically held to have spiritual power. According to the book, when a rich man made a flat mochi from leftover rice and shot an arrow at it, the mochi transformed into a white bird and flew away, and after that, the man's rice field became desolate and barren. In the Bungo no kuni fudoki, compiled in the late 8th century in the Nara period, a legend concerning mochi was described. According to archaeological research, the homemade production of mochi increased beginning in the 6th century ( Kofun period), when earthenware steamers became popular in every household, mainly in eastern Japan. The cultural significance of mochi in Japan is unique, though it has elements in common with other auspicious foods in other Asian countries. Red rice was the original variant used in the production of mochi.

The process of steaming glutinous rice and making it into a paste is considered to have its origin in ancient China, and to have been introduced to Japan from Southeast Asia some time after rice cultivation was introduced to Japan at the end of the Jōmon period ( c. 9 Chemistry and structural composition of glutinous rice.
