Pingshu yaoshi lun 評書藥石論

Pingshu yaoshi lun 評書藥石論 is an essay on shortcomings and faults in calligraphy written during the written during the mid-Tang period 唐 (618-907) by Zhang Huaiguan 張懷瓘 (mid-8th cent.), who is known for his book Shuduan 書斷.

The title of the essay establishes an analogy with a superior type of calligraphy which is strong and rounded, whereas angularity and "excess flesh" (zhirou 脂肉; i.e., overly thick strokes) are seen as flaws and weaknesses, requiring the diagnosis of a good doctor, and special treatment by medicine and minerals (yao shi 藥石). The text was submitted to the imperial throne as an instruction for the emperor's practice of calligraphy.

Zhang embeds the mastery of calligraphy into the wider field of wisdom and understanding. A master calligrapher could be compared with a Daoist master who understands methods without being bound by them, ultimately leading to a state where one transcends fixed rules. "The true measure of the art", Zhang says, "lies in its unpredictability." (Yi bu ce wei liang zhe, shu zhi miao ye 以不測爲量者，書之妙也。) The author criticises some contemporary calligraphers for focusing too much on superficial aspects (represented by "flesh", rou 肉) while neglecting the underlying structure and strength (represented by "sinews", jin 筋). The metaphor of mixing fragrant herbs with foul odours suggests a lack of discernment, resulting in a homogenisation of their art that obscures their true potential. He says, "If sinews and bones cannot support the flesh, in a horse, it becomes a nag (nutai 駑駘); in a person, it leads to obesity; in calligraphy, it becomes a 'black pig' (rouzhu 墨豬; an unrefined, clumsy piece of writing). The author emphasises the importance of natural, smooth strokes in calligraphy that "follow Heaven's principles" (shun qi tian li 順其天理). Overly angular or rigid lines are seen as defects rather than indicators of skill or strength, highlighting the value of grace and fluidity in the art.

Mastering calligraphy involves a deep, intuitive understanding that aligns the mind and hand, akin to the precise craftsmanship of a wheelwright. Such mastery is beyond verbal explanation, which is why even renowned calligraphers did not rely on words to convey their art. Zhang stresses that throughout history, emperors were interested in calligraphy and rewarded the most outstanding artists. He compares the expertise of master calligraphers with victorious generals' understanding of the overall situation and the ability to develop strategies with flexibility. The summary points out that just like success or failure in governance can only be judged in later ages, the value of calligraphic works will be judged by future generations.

The essay is quoted in the book Shuyuan jinghua 書苑菁華 and included in the series Lidai shufa lunwen xuan 歷代書法論文選.