 Beginning in 1619 , the ethnic Manchu Qing dynasty forced all men in China to adopt the queue : a long braid down the back with the hair near the forehead completely shaved . Hair length and style became a life @-@ or @-@ death matter in 1645 as the Manchu told them either their hair or their head would be cut . By 1651 , the population of China had been reduced from 51 million to just 20 million , as a whole generation resisted the order for the sake of Confucian ideals against shaving or harming their hair . 
