In the traditional culture of China, "13" is an auspicious number, representing good luck and happiness. At the birthday party, ordering 13 is also a wish for the elderly to live a long and healthy life.

In addition, in the traditional customs of China, the dishes of birthday banquets are generally moral and symbolic. For example, fish represents more than a year, chicken represents family happiness, tofu represents health and safety and so on.

In short, the 13 course of the birthday banquet not only means wishing the elderly a long and healthy life, but also includes respect and care for the elderly.