Wangjin is a kind of traditional headband worn by adult men in Chinese Ming Dynasty, Korean Joseon period, Vietnam Later Lê dynasty to Nguyễn dynasty and Ryukyu Kingdom to hold their hair in place after the topknot is done. It is usually made by weaving dyed horsehair.
According to the legend, the earliest people who wore wangjin were the Taoist priest. One day, The Hongwu Emperor of Ming Dynasty wore common clothes to visit the folk and he saw a Taoist priest wore wangjin on top of his head. The Emperor asked the Taoist priest what is it and then the Taoist priest answered "This is wangjin, wear it on top of your head, then your hair will gather together" (ref. "此曰網巾. 裹以頭, 則萬髮俱齊"). The Emperor was really satisfied with this answer that contained meaning of united the country. After the Emperor returned to his palace, he ordered that all the men in the country including the emperor to the ordinary people must wear wangjin on their head. Since then, Wangjin became common headgear of adult men in the entire country. After the collapse of the Ming Dynasty, the Manchu people established the Qing Dynasty, and due to the Manchu government policy that banned Chinese people from wearing Hanfu and forced them to shave their hair and wear a queue, the use of wangjin in China came to an end.