The Gegu yaolun 格古要論 "Important discussions about assessing antiques" is a treatise on collecting and assessing antiques. It was written by the early Ming period 明 (1368-1644) collector Cao Zhao 曹昭, courtesy name Cao Mingzhong 曹明仲, who came from Songjiang 松江 near modern Shanghai. His book was finished in 1387 and is divided into 3 juan "scrolls" that describe antiques in 13 topics: ancient bronze vessels, paintings, calligraphies, rubbings of model inscriptions in stone steles, ancient music instruments, inkstones, marvelous stones (zhuqi 珍奇, i.e. jade, agate, pearls, rhino horn or ivory), metal objects, earthenware and porcelain, lacquerware, textile objects, extraordinary wooden objects, and strange stones. Each chapter is divided in between 5 and 40 paragraphs. All these various collectives are described in very much detail, but it does not cover all objects that were rated as precious among collectors. Lang Ying 郎瑛, for instance, criticized in his book Qixiu leigao 七修類稿 that Cao Zhao only mentions zithers (qin 琴) and not wind instruments (shengguan 笙管), and that he might have added other descriptions about model calligraphies, and not only the Chunhua jie 淳化帖. Among the jewellery, the zumulü 祖母綠 and shengtie 聖鐵 are missing, and among the extraordinary stones, the Dali xiangu 大理仙姑 might have been mentioned, and so on. The critic does disregard Cao Zhao's principle only to write about objects that he had personally inspected, for instance, in the collection of his father Cao Zhenyin 曹真隱, and that his book therefore cannot be interpreted as an encyclopedia about antiques and collectibles. There is one statement in the Gegu yaolun that really deserves critique, namely the assumption that bronze vessels, buried into the earth, preserve a fresh turquois colour (cui 翠) for a thousand years, and if kept under water, a green colour (lü 綠). Sun Jiong 孫炯, author of the Yanshanzhai zhenwan jilan 硯山齋珍玩集覽, doubts this general statements and says that the colour depends on the colour of the water and the earth.
The Gegu yaolun is included in the collectanea Gezhi congshu 格致叢書, Xiyinxuan congshu 惜陰軒叢書, Yimen guangdu 夷門廣牘, Baijia mingshu 百名家書, Yingyin Yuan-Ming shanben congshu shi zhong 影印元明善本叢書十種 and Siku quanshu 四庫全書. The version in the Gezhi congshu is an abbreviated edition. There is a revised and annotated edition published by Wang Zuo 王佐 and Shu min 舒敏 with a length of 13 juan and called Xinceng Gegu yaolun 新增格古要論. It was published in 1459. Wang Zuo, style Zhuzhai 竹齋, hailed from Jishui 吉水, Jiangxi. He added information about calligraphies, model calligraphy boards (gubei fatie 古碑法帖), and supplemented quotations about bronze tools and stones, paintings and and "objects of the study" (wenfang 文房, i.e. brush, instone, ink, paper, brush rack, water pot). The also altered the sequence of the chapters into the following order: Zithers, calligraphy, bronze inscriptions, paintings, precious stones, inkstones, stones, porcelain, lacquerware, brocade, wood, bamboo, the objects of the study, short critical comments (gaochi tiba 誥敕題跋), and various investigations (zakao 雜考). Experts rate Wang Zuo's additions as qualitatively lower than the original text of Cao Zhao.
Li Xueqin 李學勤, Lü Wenyu 呂文鬰 (1996). Siku da cidian 四庫大辭典, vol. 2, p. 2001. Changchun: Jilin daxue chubanshe.
Zhou Zheng 周錚 (1993). "Gegu yaolun 格古要論", in: Zhongguo da baike quanshu 中國大百科全書, Wenwu bowuguan 文物•博物館, p. 170. Beijing/Shanghai: Zhongguo da baike quanshu chubanshe.
Xu Pingfang 徐蘋芳 (1992). "Gegu yaolun 格古要論", in: Zhongguo da baike quanshu 中國大百科全書, Kaoguxue 考古學, p. 136. Beijing/Shanghai: Zhongguo da baike quanshu chubanshe.
1. 古銅器 Gu tongqi Ancient bronze vessels
2. 古畫 Gu hua Ancient paintings
3. 古墨蹟 Gu moji Ancient calligraphies
4. 古碑法帖 Gu bei fatie Ancient stone slab inscriptions and model calligraphy boards
5. 古琴 Gu qin Ancient zithers
6. 古硯 Gu yan Ancient inkstones
7. 珍奇 Zhenqi Marvellous gems
8. 金鐵 Jintie Metal objects
9. 古窯器 Gu yaoqi Ancient pottery and porcelain
10. 古漆器 Gu qiqi Ancient lacquerware
11. 錦綺 Jinqi Brocade and gauze
12. 異木 Yimu Extraordinary pieces of wood
13. 異石 Yishi Extraordinary stones