What day is September 9th? What about the lunar calendar?

September 9 is a date, the ninth day of the ninth lunar month, which is the traditional Double Ninth Festival. The ninth day of the ninth lunar month is the traditional Double Ninth Festival, also known as the "Old People's Day".

Because the Book of Changes defines "six" as the number of yin and "nine" as the number of yang, on September 9, the sun and the moon are combined with yang, and 29 is heavy, so it is called Chongyang, also known as the Double Ninth Double Ninth Festival, which was formed as early as the Warring States Period. In the Tang Dynasty, the Double Ninth Festival was officially designated as a folk festival, and it has been used ever since.

The name of "Double Ninth Festival" was recorded in the Three Kingdoms period. According to Cao Pi's "Nine Days Zhong You Book", it is recorded: "The year is from September to September, and suddenly it is September 9. Nine is the number of yang, and the sun and the moon coincide. It is well-known and thinks it is suitable for a long time, so it is a feast. "