"Purple gas comes from the east", which is one of the reasons of Taoism. Canon out the biography of Guan Ling Yin. Later, many biographies of Taoism have similar records. It is said that the founder of the old man, Taoism (Taoism calls him the old gentleman), is ready to leave the Zhou Dynasty and live in seclusion in the face of the declining world. Legend in Youlong says that the old son will go to the desert country in the west to teach foreign nations. Therefore, there is a purple gas moving from east to west, and one of them goes straight to the mouth of Dahan Canyon. Yin, the husband of King Zhao of Zhou, is good at observing the stars in the sky. Knowing that a saint was going to pass Hangu Pass, he resigned his official position and went to Hangu Pass to be a customs officer. He held a ceremony of fasting and burning incense on both sides of the road, cleaning up along the way and waiting for the arrival of the saints. Before long, the old son rode a green cow and slowly walked into Hangu Pass. Guan ordered Yin to worship Laozi as a teacher and asked Laozi to write the Tao Te Ching, which has been circulated for thousands of years.
Among China people, purple gas comes from the East and is a symbol of good luck, which is regarded as a theme in many literary works. For example, Chapter 77 of "Shen Feng Yan Yi" is an example. This work is written according to various doctrines and articles, and it is quite interesting to read because it is artistic and artistic. In the past, during Chinese New Year, people always put up Spring Festival couplets with "purple gas coming from the east", which shows that the story of the old son believing in Gu Guan has been sung for a long time.