Library

Is it not difficult to establish words (write a book)? Some works elaborate on complex and profound matters yet fail to grasp the key points; others merely present a rough outline, causing both the origin and evolution of the subject matter to remain obscure. The errors in these two cases are roughly equal. Therefore, being concise is preferable to being exhaustive. One must not only clarify "what it is" (the obvious), but also uncover "why it is so" (the underlying rationale). This is just like classical texts and their commentaries: Han and Tang commentaries were indeed very detailed, whereas Song scholars simplified the study of names and objects to exhaustively explore principles and reasoning. Thus, the Way of medicine became as clear as the sun and stars.

Today, *Bencao Gangmu* (Compendium of Materia Medica) in medicine serves much like commentaries do for classical texts. Many people study all their lives without understanding the value of commentaries, and doctors treat *Bencao Gangmu* in the same way. Fearing its voluminous nature and the difficulty of memorization, they are startled by its vastness like the Milky Way and find it hard to synthesize. Consequently, they stick to陋 (shoddy/simplistic) methods, inherit errors, and repeat mistakes. Those who casually experiment with medicinal doses claim to be skilled physicians, while those sitting in high chairs pose as renowned elders are everywhere. This is truly sigh-worthy.

Mr. Ye from Guwu was a Confucian scholar who was profound in the *I Ching* (Book of Changes) and skilled in medicine. He used the principles of waxing and waning, increase and decrease from the *I Ching* to understand the slow/fast and heavy/light properties of prescriptions. He wrote books piled up to his height, one of which is *Bencao Jingjie* (Explanation of the Classic of Materia Medica). Regarding the 365 species in the original *Shennong Bencao Jing* (Divine Farmer's Materia Medica), he reduced some and added others, totaling 174 species. His interpretations are detailed and clear; his prescription formulations are thoroughly considered and perfect. Li Shizhen's (Dongbi's) work is broad and comprehensive, whereas this book extracts the most essential points, remaining pure, quiet, refined, and subtle. It indeed follows the methodology of philosophical exegesis. Establishing such a discourse achieves the three immortals (immortality of virtue, merit, and words).

Mr. Wang Yuetian from Xishan, a relative of the Haidian Zhuangyuan (Top Scholar), studied the *I Ching* under Mr. Ye and also acquired the art of saving lives. He occasionally showed me this book. After careful examination multiple times, I regarded it as a critical work akin to *Lunheng*. How could I bear to let it remain secret? Recently, my father, during his leisure from official duties, published several medical formula books to supplement the inadequacies in benevolent relief efforts and support the elderly. Since drugs are the tools of treatment, we also engraved this book, hoping that learners would take it as a guide. Just as a scholar, even if unable to trace back far or explore profound erudition, can still be a true Confucian by strictly adhering to Song commentaries, thinking deeply, playing with the meaning, and achieving mastery through integration. This is the original intention of Mr. Ye's writing, the elegant intent of Brother Yuetian, and also my father's sincere affection for protecting children and his desire to benefit people. We should practice this according to circumstances, which aligns with the long-held ambition of my brothers and me.

Upon completion of the work, I record this at the beginning of the manuscript.
Preface written by Yang Jizu from Hedong at Jingde Hall in the Sixth Office, during the first ten days of the fifth month, in the year Jiachen of the Yongzheng reign (1724).