In ancient China, how do men shave, there are people who can not grow a beard?

Ancient people are to keep a beard, generally from the beginning of adulthood to keep a beard, adult standards in the dynasty is not the same, the Han Dynasty is 16 years old, the Tang Dynasty began to be 18 years old, and later changed to 22 years old. Keep a beard according to the "body hair and skin, by the parents, do not dare to damage" Confucian moral is not cut, but not many people really a back not cut hair and not cut the beard, stay dragged to the ground. So the custom of the ancients is that the beard and hair can not be destroyed at will for no reason, but daily trimming and combing is possible.

I remember when I used to watch the Three Kingdoms, He Jin killed eunuchs, is to "no beard" to judge, as long as there is no beard when the eunuchs killed, visible beard is a man's mark at that time.