Marx famously said, "An industrial system is determined by its production tools and methods." If writing is regarded as an industry, it is a production tool, which can be divided into two categories: one is related to the body, that is, the heart and hand mentioned in Book Theory; One that has nothing to do with the body is pen and ink.
The ancient production method is brushwork, including holding and lifting. In traditional terms, it is a desk book and a pen-tip book. Before the middle of Ming Dynasty, people in China wrote mostly on the table, and the characters were mostly small. After the middle of the Ming Dynasty, calligraphy began to hang on the walls, and books such as Zhang Zhi, nave and couplets were all big characters.
During the Tang and Song Dynasties, the sitting posture of calligraphy changed. People in the Jin and Tang Dynasties often sat on the floor, leaning against a low chair, holding paper in their left hand, a pen in their right hand, and often holding a three-fingered pen. Mr. Qi Gong also mentioned this point. After the Song Dynasty, people began to sit on tall tables and chairs. Everyone changed to holding the pen with five fingers, but there are exceptions, such as Su Dongpo, who still holds the pen with three fingers.
Therefore, Su Dongpo has a famous saying that "there is no fixed method in writing, but it is loose and wide". Generally speaking, people sit on the ground, holding paper in their left hand and writing with a pen in their right hand, and their movements will be lighter. The stroke thickness of the same character is similar, because the paper can't stand the force and doesn't change much.
With the change of sitting posture, the fingering gradually decreases. When a person holds a pen and turns with his thumb, his fingertips turn to his palm, which is called introversion, and the palm turns to the extension of screaming. The difference between Wang Xizhi's brushwork and that of Wang Xianzhi lies in Wang Xizhi's brushwork from the outside to the inside, as do the brushwork of Yu Youren, Qi Gong and Xinyu Pu.
Wang Xianzhi turns to both sides, which can be called "revolution" and "rotation" here, that is, turning the pen with fingers and turning the wrist and arm. The latter rotates with a larger radius than the former. If it's just a rotation, it's an inward bending method, because turning right in one direction will always turn to the end. Therefore, in the past 1700 years, no matter Wang Xizhi or Yu Youren, most of their writings were out of touch.