After Becoming Emperor Qin Shi Huang, he immediately began to implement a series of measures to strengthen the centralization of power, including the system of clothing and clothing, but because Qin Shi Huang was in power for too short a time, the dress system was only a start-up, not complete enough, but unified in the color of clothing.
Qin Shi Huang was deeply influenced by the theory of the Five Elements of Yin and Yang, and believed that Qin Kezhou should be water and fire, because the Zhou Dynasty was a fire that won gold and the color was still red, then Qin Shengzhou was water virtue, and the color advocated black. Therefore, in the Qin Dynasty, black was a noble color, and Qin Shi Huang wore a black dragon robe.
Later, in the Sui and Tang dynasties, the golden dragon robe became the exclusive property of the emperor, and the people were not allowed to wear golden clothes, otherwise they would commit the crime of killing their heads, and the yellow robe officially became a symbol of imperial power.
After the Chen Qiao Mutiny, which began with the yellow robe of Zhao Kuangyin, the grandfather of the Song Dynasty, after which the emperor began to decide not to wear the same color of clothes for the same ordinary people, so Tang Gaozu ordered the common people not to wear yellow clothes, and since then, yellow has always been the noblest color, which is the exclusive property of the royal families of all dynasties. This is why only Qin Shi Huang wore black dragon robes, while future emperors did not wear them.