Shuduan 書斷

Shuduan 書斷 "Judgments on calligraphies" is a book on the critique of calligraphy written during the mid-Tang period 唐 (618-907) scholar Zhang Huaiguan 張懷瓘 (early 8th cent.). He hailed from Hailing 海陵 (modern Taizhou 泰州, Jiangsu) and was an assistant (gongfeng 供奉) in the Hanlin Academy 翰林院. He was famous for his mastering the styles of the standard script (zhenshu 真書), the cursive "running script" (xingshu 行書), and the super-cursive "grass script" (caoshu 草書), and his expertise in the small seal script (xiaozhuan 小篆) and the broad chancery style (bafenshu 八分書). Of his writings, only the Shuduan has survived, as well as the essays Shuyi 書議, Shugu 書估, Pingshu yaoshi lun 評書藥石論, Guwen dazhuan shuzu 古文大篆書祖, Liutilun 六體論 and Yongbi shifa 用筆十法.

The book Shuduan with a length of 3 juan is an analysis of the works of famous ancient masters in calligraphy, like Gu Kaizhi 顧愷之 (c. 348-c. 405), Lu Zhenwei 陸探微 (d. c. 485) or Zhen Sengyao 張僧繇 (b. 479). In the first fascicle of the book, ten various styles of script are explained, from the ancient script (guwen 古文) and the large seal script (dazhuan 大篆 or zhouwen 籀文) to the small seal script, the normal chancery script (lishu 隸書), the bafen style, the isolating grass script (zhangcao 章草), the "flying white" style (feibai 飛白) with blank spaces inside of brush strokes, and the genuine grass script. Zhang Huaiguan describes the origin, history and use of these styles and assesses their meaning in the field of calligraphy.

The second and third juan provide ratings of calligraphers and their work. They are ranked according to three categories, namely "inspired" (shen 神), "outstanding" (miao 妙), and "competent" (neng 能). The first and best category includes 25 works, the second category 98 creations, and the third category 107 oeuvres. There are 68 persons included, plus 38 in an appendix, to which Zhang Huaiguan also provides short biographies. These are important because many of the ancient calligraphers were not known through official biographies.

The Shuduan is included in Zhang Yanyuan's 張彥遠 (early 8th cent.) book Fashu yaolu 法書要錄, and in the series Baichuan xuehai 百川學海, Gezhi congshu 格致叢書, Shuofu 說郛 (Wanwei Shantang 宛委山堂 edition) and Siku quanshu