Bright yellow used to be royal’s color in the history of China, exclusively. However, it was originally a popular color for everyone.
In an ancient legend, the Dragon Ying Long had assisted King Huang defeated his enemy and built a prosperous kingdom. This Dragon Ying Long, in Chinese Mythology, is guarding in the middle section of the heaven, which is representative of the color yellow and the earth.
Bright yellow is also the color of the shining sun, as well as many important crops like wheat and rice. Therefore, as a big agricultural civilization, bright yellow became more and more honorable in Chinese culture.
Since Han Dynasty (202 B. C. - 220), royals started to add yellow decorations to their clothing. Until Tang Dynasty (618 - 907), bright yellow was exclusively used by the royal family. After Emperor Zhao Kuangyin put on a yellow dragon robe and claimed himself emperor, bright yellow officially became representative of honorable monarch and paramount power in the history of China.
Hundreds of years later, the royal family had extended their use of bright yellow to architecture. The royal palace Forbidden City, built by Emperor Zhu Di of Ming Dynasty, applied bright yellow to all of the rooftops.
Nowadays, though people could wear any color they want, yellow is still a lucky color in Chinese culture.