The term originally refers to the texture of muscle, and later by extension it refers to well-organized principles in things. As a literary term, it was first used by Weng Fanggang, a Qing-dynasty scholar, to refer to two aspects:yili（义理reasoning）andwenli（文理structure）. The former is about views or reasoning, primarily concerning Confucian thinking and learning expressed in poetry, whereas the latter represents texture of poetry, especially poetic structures, metrical schemes and rhythms, and other techniques of writing. Scholars of the Xingling School(School of Inner Self) of the Ming and Qing dynasties advocated rejecting dogmatic guidelines and expressing one’s emotions and thoughts in literary works, while adherents of the Shenyun School(School of Elegant Subtlety)believed in subtlety and implicitness expressed through poetry. Criticizing both literary trends, Weng promoted the principles and techniques of the Song-dynasty poetry. In terms ofyili, he emphasized the need to follow classical Confucian tradition and erudition. In terms ofwenli, he advocated exquisite intricacy, attention to details, and graceful structures with a great many variations, as well as the need to convey a substantive message. During the reign of Emperor Qianlong and Emperor Jiaqing of the Qing Dynasty, a boom in the study of Confucian classics and textual research led to the emergence of the Jili School(School of Reasoning and Structure). Weng advocated integration of form and content in poetry, thus promoting the development of poetry based on classic learning. However, his overemphasis on classic scholarliness in poetry was criticized by scholars of both his age and later generations.
I don’t care if my views differ from those of others, nor do I care if the differing views are from ancient scholars or my contemporaries. What I do care is analyzing carefully the structure and reasoning of writings in order to arrive at a balanced view.(Liu Xie:The Literary Mind and the Carving of Dragons)
Yili in Confucian classics is all about structure and reasoning in writing, i.e., the texture and proper presentation of writings. (Weng Fanggang:Preface to Collection of My Works)
Today’s men of letters are in an era when Confucian studies are flourishing. It is therefore imperative that scholars base their study on research and verification, and that poets focus on the structure and reasoning of their works. (Weng Fanggang:Preface to Collection of My Works)