It is said that from the Shunzhi era to the early Kangxi era, a period of forty years, people from outside the prefecture referred to Hangzhou (Wulin) as the "pool of medicine" (a gathering place for medical experts). This was likely because at that time, Mr. Lu Jingong (Lu Jin), using Zen Buddhist principles to corroborate medical theories, frequently achieved efficacy in treating rare and difficult diseases, thereby shaking the world with his fame. Mr. Zhang Yinan (Zhang Yin'an) rose subsequently, his fame being comparable to Lu's. He constructed the Lushan Tang (Hall of Companioning Mountains), inviting fellow students, friends, and disciples to lecture within, referencing the similarities and differences in classical texts to distinguish right from wrong. Consequently, scholars discussing the learning of Huangdi (Yellow Emperor) and Qibo (Qibo) all yearned to study under these two masters, reaching an unprecedented peak of prosperity. The books authored by both masters were worthy of passing down through generations; the works edited by the Zhang family had already been woodblock printed and circulated. Yet, barely a century later, the number of circulating copies had dwindled. Among them, *Zhenjiu Michuan* (Secret Transmission of Acupuncture and Moxibustion) and *Lushan Tang Leibian* (Classified Debates of Lushan Hall) had become difficult to acquire. I searched for many years before finally obtaining *Lushan Tang Leibian*. Observing its adherence to ancient standards while evaluating contemporary practices, analyzing doubts, and correcting errors, it serves as a sufficient compass and square (standards and norms) for future learners. It is urgent to reprint it to broaden its dissemination. If future scholars take this as their guide, they may hopefully attain the correct path, and by following it, how could there be confusion on divergent paths or errors on crooked trails?

Zhang Yinan initially served as a clerk for the Grain Transport Commissioner (Liangdao). The Commissioner suffered from Longbi (urinary retention/obstruction), and various physicians' medications proved ineffective. Someone recommended Zhang Yinan. Zhang prescribed Buzhong Yiqi Tang (Tonify the Middle and Augment Qi Decoction), and the patient recovered after one dose. When asked, "Others used diuretic drugs without effect, yet you used ascending and lifting drugs with success; what is the rationale?" Zhang replied, "Have you not seen a water-drawing device? If you block the top and invert it, not a single drop can flow out; remove the blockage at the top, and the water flows naturally. Is this not the method?" Reading the explanations in this book, the principle that to drain downwards, one must first lift upwards, illustrated by the rope of a windlass, is precisely this logic. If people can apply this method to understand related matters through analogy, the methods of medicine are indeed inexhaustible! Regarding this matter, I heard Mr. Huang Guanshi explain it thus. Recently, I also heard Mr. Zhang Dongfu state that when Lu Jingong handled affairs for the Grain Transport Commissioner, the Commissioner suffered from internal obstruction with inability to urinate, a critical situation where all physicians were at a loss. Lu Jingong prescribed Ren Shen (Ginseng Radix et Rhizoma) and Ma Huang (Ephedrae Herba), each one liang (approx. 37g), as a fixed dose. The other physicians hesitated and dared not endorse this prescription, but the Commissioner did not doubt it and drank the medicine. Before long, urine flowed, and the delighted Commissioner gifted Lu Jingong a thousand taels of gold. This differs from what I previously heard. My opinion is that Masters Lu and Zhang treated different cases, but the stories told by those involved were conflated onto the Grain Transport Commissioner, leading to discrepancies and doubts. Friends Huang and Zhang are not given to falsehoods, so I record both accounts here as methods for treating Longbi, and also to testify that this volume contains abundant profound theories and exquisite words. People should exert their thoughts and carefully contemplate to reap benefits, and certainly should not regard it as superficial and trivial, neglecting it.

Recorded on the Wuzi day of the third month, Ji Chou year of the Qianlong reign, by Old Man of Xushan, Wang Qi.

Recalling the end of the Jiazi year, I traveled back and forth between Hengshan and Daling due to business. Resting on the road at a farmhouse, the farmers were slaughtering a pig and dissecting its foreleg, from which clear fluid flowed, approximately two sheng (approx. 2 liters). Surprised, I inquired. The farmer's son said, "This pig has suffered from weak legs, unable to walk or stand since infancy, always lying down to eat. This is the origin of its illness." From this, I realized that human ailments involving limbs that are unfit for holding objects or walking are likely caused by the stagnation of dampness-water qi within the body, similar to this case. Now, reading Zhang Yinan's records, he inferred from the presence of roundworms (Ascaris lumbricoides) in a pig's intestine that healthy humans do not harbor such worms. This matter can indeed be observed by analogy. On the Gengzi day, three days after Guyu (Grain Rain solar term), having finished collating and proofreading, I reread this section and appended this note with my pen.