Purple gas comes from the east, auspicious light from the south and happiness from the west.

This is an ancient couplet. Literally, auspicious sunshine comes in the south, endless wealth comes in the north, honor and extravagance come in the east, and continuous prosperity comes in the west. Generally speaking, it is an auspicious blessing. In the old saying, the southeast and northwest, when spoken separately, generally do not refer to a certain direction, just for the sake of the neatness and rhythm of couplets. For the simplest example, the most appropriate explanation of "buying horses in the east market, saddles (jiān) in the west market, bridles (pèi) in the south market and whips in the north market" in Yuefu poem Mulan Ci is "buying harnesses everywhere in the market".

China is located in the northern hemisphere, in the eastern part of Eurasia. Most of the land is located in the north of the Tropic of Cancer (23 degrees 26 north latitude), and the sunshine comes from the south all the year round. Houses facing south are easy to take sunlight. Sunshine has many benefits to people: First, it can keep warm, and the temperature in the south room is 1-2 degrees higher than that in the north room in winter; The second is to participate in the synthesis of vitamin D in human body, and children often bask in the sun to prevent rickets; Third, ultraviolet rays in sunlight have bactericidal effect; Fourth, it can enhance human immune function.

South Suzaku, North Xuanwu, East Qinglong and West White Tiger. In geomantic omen, the dragon is strong and the tiger is weak. Qi is the origin of all things, Tai Chi is Qi, and two instruments are born from one accumulation, and three and five elements are used in one life. Soil is derived from Qi, water is derived from Qi, and people are derived from Qi, and Qi feels it. Everything is not related to Qi. Besides, in ancient times, purple gas generally represented dragon gas, and dragons came from the east, so purple gas came from the east! In contrast, the tiger is blessed!