Siti shushi 四體書勢

Siti shushi 四體書勢 "Momenta in the four writing styles" is an essay on writing and calligraphy written during the late Western Jin period 西晉 (265-316) by Wei Heng 衛恆 (d. 291), courtesy name Jushan 巨山, from Anyi 安邑 in the commandery Hedong 河東 (today's Xiaxian 夏縣, Shanxi). He held the office of gentleman attendant of the palace gate (huangmen shilang 黄門侍郎) and was famous calligrapher of his time.

Wei Heng explains the emergence and use of the four writings styles "ancient script" (guwen 古文), seal script (zhuanshu 篆書), chancery script (lishu 隸書) and grass script (caoshu 草書) and introduces the most important masters in each of these four styles. At the end of each chapter, the author adds positive evaluations, the first two of which were written by himself, namely Zishi 字勢, and Lishi 隸勢, and the others quotations from related texts, namely Cai Yong's 蔡邕 (132-192) Zhuanshi 篆勢, and Cui Yuan's 崔瑗 (78-143) Caoshu shi 草書勢. The essay is important because it is a history of the Chinese script and of its interpretation. It includes information about early attempts to discern different types of characters (liu yi 六義), the history of the transformation from the seal script to the clerical script usable in daily administrative communication and the process of character simplification.

The text is included in Wei Heng's biography in the official dynastic history Jinshu 晉書 (ch. 36), the series Shuofu 説郛, Wuchao xiaoshuo 五朝小說, Wuchao xiaoshuo daguan 五朝小說大觀, Yuhan shanfang jiyi shu 玉函山房輯佚書 and the books Shuyuan jinghua 書苑菁華 and Lidai shufa lunwen xuan 歷代書法論文選.