The writing brush entered a new stage of development in the Han dynasty. First, it created the decoration craft of engraving and inlaying on the pen-holder. Second, some writings on the production of writing brush appeared. For example, the first monograph on the selection, production and function of writing brush was written by Cai Yong in the eastern Han dynasty . Third, the special form of "hairpin white pen" appeared. Officials in the Han dynasty often sharpened the end of the brush and stuck it in their hair or hat for their convenience. Worshipers also often put pen on their heads to show respect.