I feel that he actually refers to the four corners of the house, and the middle refers to the house, which is an image metaphor of the four corners of the ancient house. In ancient times, people often used figurative metaphors to refer to a place in their house, so there was such a legend, and this figurative metaphor was often used in modern building.
Second,? Astronomical research
In ancient times, some people who could see the world generally observed the astronomical phenomena facing south, because they thought it was more accurate, and people could predict the weather changes by looking at the astronomical phenomena, so many people could see the world, and their predictions were particularly bloated. Moreover, according to the regularity of Suzaku and Xuanwu Qinglong White Tiger, they thought it was the most correct way to observe the astronomical phenomena.
Third,? feng shui
Because the ancients in China advocated the unity of heaven and man, most of them had a principle in the location of the capital, villages, small houses, tombs and even the hearth bed used in our lives, so at this time, except for the previous Suzaku, everything in the middle of Xuanwu Right Qinglong Left White Tiger changed with the situation, which can be said to be the feng shui of cities, villages and stoves.
In some people's eyes, the theory of five elements prevailed in the Tang Dynasty, and in this era, the story of Qinglong began to become popular gradually. Artists of the five elements decorated the southeast and northwest with various colors according to the yin and yang and the five elements, and also decorated them with various sacred colors, thus becoming the saying that "left Qinglong right white tiger, former Suzaku back Xuanwu".