The oriental black dragon has seven nights: horn (dragon's horn), kang (neck), edge (neck root), square (rib), heart (heart), tail (tail) and dustpan (tail). These seven stars are like dragons flying in the night sky in spring, so they are called "Oriental Black Dragons". Qinglong belongs to wood in the five elements.
There are seven nights in North Xuanwu: fighting (dǒu), cattle, women, air, danger, houses and walls. The seven nights of North Xuanwu, in the night sky in winter and early spring, appear like snakes and turtles, so it is called "North Xuanwu".
Seven nights of the West White Tiger: Kui, Lou, Stomach, Chang, and Shen. The five elements belong to gold and white in color, so they are called white tigers.
Seven nights in South Suzaku: well, ghost, willow, star, Zhang, wing and Zhu (zhěn). Southern Suzaku is called "Southern Suzaku" because it appears in the night sky in late summer and early autumn. The south of the five elements belongs to fire. Phoenix has the characteristic of "Nirvana _ Rebirth", so Suzaku is also called "Fire Phoenix".
The extended data contains several stars every night. As an important part of China's traditional culture, it has been widely used in ancient astronomy, religion, literature and astrology, astrology, geomantic omen, lucky choice and so on.
Different fields give it different connotations, and the related content is very complicated.
At present, the twenty-eight lodging system can be traced back to the early Shang and Zhou Dynasties, and it was complete in the Spring and Autumn Period and the Warring States Period. Records of twenty-eight hotels and four elephants were first recorded in the early Warring States Period.
In terms of cultural relics, the lacquer box of the tomb of Zeng Houyi of the Warring States period unearthed in Suixian recorded the complete names of 28 hotels for the first time. It is recognized by historians that Twenty-eight Nights was first used in astronomy, so its position in the history of astronomy is quite important and it has always been a topic of interest to Chinese and foreign scholars.
Baidu encyclopedia -28 stars