What is the 29th day of the first month of the lunar calendar, what are the traditional customs and what should I eat?

It is the Festival of Filial Piety, also known as the Festival of Arguing Nine.

The Au Jiu Festival is a traditional folk festival in the Shiyi area of Fuzhou, Fujian Province, dated on the twenty-ninth day of the first month of the lunar calendar. On this day, every family has to cook the congee for ancestors or give it to friends and relatives; women who have been married have to send the congee back to their mother's house to honor their parents.

This custom is still prevalent in Fuzhou. An old mother who drank the "au jiu congee" said, "au jiu congee" is not only brown sugar, peanuts, jujubes, cinnamon and so on, but also has a filial piety of the children, sweet to the heart.

Extended information:

The significance of the Festival of Filial Piety:

The Festival of Filial Piety was interpreted as a social trend of honoring the elderly and respecting filial piety, which was carried forward in Fuzhou.

In the "Festival of the Argumentative Nine", Roulei Village, Chenmen Town, Cangshan District, Fuzhou, set up a grand "filial piety feast" in the Chen Ancestral Hall;

The Ancestral Hall was filled with one hundred and ninety-five tables, and nearly 2,000 elderly people over the past 100 years were seated on the seats while leisurely chatting and eating delicious food. The village's young people are busy, serving food and tea. This is a custom of the feast on the Day of Respect for the Elderly, which has been inherited by the local community for more than twenty years.

Baidu Encyclopedia - Filial Piety Festival