It is suggested that Cao Quanbei write with a double-sided brush with a diameter of 5- 10 mm, because most people who ask such questions are beginners, and skilled people can better reflect the charm of writing by Yang Hao.
Some people say that a good book does not choose a pen. Yes, great calligraphers, such as Wang Xizhi and Yan Zhenqing, can write with any pen. For beginners, it is best to have a satisfactory pen. The pen used for official script must be suitable for reverse writing. Pure wool brush is too soft and almost inelastic, which is not suitable for beginners to practice!
As a beginner, a brush with moderate elasticity is the most suitable. The creation of official script requires extremely high quality, so we should follow the advice of the instructor.