1. The compilation of this book is specifically intended to analyze and annotate Zhang Zhongjing's *Shanghan Lun* (Treatise on Cold Damage). However, Zhang Zhongjing's discussion on cold damage is actually based on the *Suwen: Re Bing* chapter of the *Huangdi Neijing* (Yellow Emperor's Inner Canon), and his division of the Six Channels (Taiyang, Yangming, Shaoyang, Taiyin, Shaoyin, Jueyin) does not go beyond the scope of the *Ling Shu: Jing Mai* chapters. Therefore, I have extracted texts from these two chapters and placed them before the *Shanghan Li* (General Principles of Cold Damage) as Volume 1, so that later generations may revere Zhang Zhongjing while also reverting to Huangdi (Yellow Emperor) and Qibo. Moreover, since Zhang Zhongjing himself stated "I transmit but do not create" upon completing the *Shanghan Lun*, it is evident that his discussions actually follow the principles of the *Neijing*.

2. Regarding the *Re Bing* chapter of the *Neijing*, Wang Bing (styled Taipu) provided annotations first, and Ma Shi (styled Xuantai) expanded upon them later. However, there are parts therein that are not entirely reasonable; I occasionally supplement them with my own humble insights.

3. Wang Shuhe compiled Zhang Zhongjing's formulas and discussions into ten volumes. Among them, sections such as the *Shanghan Li*, the differentiation of pulse, symptoms, and treatments across the Six Channels, as well as conditions like Yin-Yang exchange and post-illness diseases, are indeed original texts by Zhang Zhongjing and were fully included in the compilation. What was excluded includes the pulse methods in Volume 1 and the chapters on sweating, vomiting, and purging in Volume 7 and onwards, because these were additions by Wang Shuhe. As for the three syndromes of Spasm (Jing), Dampness (Shi), and Heatstroke (Yue) in Volume 2, and Cholera (Huoluan) at the beginning of Volume 7, although they are also original texts by Zhang Zhongjing, they were not included because they belong to miscellaneous diseases.

4. Zhang Zhongjing's works are the ancestors of formula literature, as the *Neijing* contains theoretical discussions but no formulas. Wang Shuhe's rise and compilation can be seen as respecting Zhang Zhongjing. However, he inserted his own opinions into Zhang's discussions, causing students to be unable to distinguish between Zhang's original words and Wang's additions. Consequently, later generations criticized him, claiming that Wang Shuhe disrupted Zhang Zhongjing's *Shanghan Lun*. Thus, his *Mai Jing* (Pulse Classic) was stolen by Gao Yangsheng, which is considered his retribution. Nevertheless, Zhang Zhongjing's books were fragmented, lost, and disordered after the wars of the Three Kingdoms period. If not for Wang Shuhe's compilation, they would not have survived to the present day, nor would Cheng Wuji have had a text to annotate. Current physicians should not merely blame Wang Shuhe's faults while forgetting his merits.

5. In Wang Shuhe's compiled chapters on the Six Channels, some Yangming and Shaoyang diseases are listed under the Taiyang chapter, and some Taiyang diseases are listed under the Yangming chapter. Some Cold Syndrome (Zhong Han) cases are mixed into Taiyang and Yangming diseases, and even into the Three Yin heat diseases. I have now corrected all these errors. All Three Yang diseases are returned to their respective Yang chapters, and the Three Yin heat diseases are returned to their respective chapters. Only the Cold Syndrome is separately divided into Upper, Middle, and Lower volumes, analyzing its syndromes as True Cold, so that learners clearly understand the distinction between Cold Damage (Shang Han) and Cold Syndrome (Zhong Han), thereby avoiding errors.

6. In Zhang Zhongjing's discussion of cold damage meridians, the book only divides them into the Six Channels without specifying Hand or Foot meridians. In reality, both Hand and Foot meridians are affected. Therefore, after the *Re Bing* chapter in the first volume, I immediately provide diagrams and annotations for the Hand and Foot Yin-Yang Six Channels according to the *Ling Shu*. My annotations primarily rely on the elaborations of Hua Shi (Slippery Master/Hua Shou). However, there are occasional errors, which I have further verified and corrected using my own insights.

7. Cheng Wuji's annotation of the *Shanghan Lun* is comparable to Wang Bing's annotation of the *Neijing*; the difficulty lies in being a pioneer. Although later scholars found many questionable points in his annotations, most of their innovations were inspired by Cheng's work. Some even forgot his contribution and instead criticized his explanations. Thus, Wang Yutai stated that Cheng's explanations are the most detailed and clear; although there are occasional self-contradictions, these are but minor flaws in a flawless jade and do not diminish its value like a city-connected jade. Some argue that Cheng's annotation merely follows the text, lamenting that he did not distinguish Wang Shuhe's words from Zhang Zhongjing's book. They fail to realize that ancient authors wrote with humility and dared not easily criticize predecessors, which is why their virtue and fame grew. People like myself also tire of speaking too much.

8. Cheng completed his annotation of Zhang Zhongjing's book and then wrote the *Ming Li Lun* (Theory of Clarification). His explanations of formulas such as Guizhi Tang (Cinnamon Twig Decoction), Mahuang Tang (Ephedra Decoction), and Qinglong Tang (Azure Dragon Decoction) are particularly clear. It is a pity that he explained only about twenty-plus formulas. For those he did not elucidate, I supplemented them largely with my own insights, drawing from the original notes and books like *Neitai Fangyi*.

9. Many have refuted the *Shanghan Li* (General Principles of Cold Damage). My current verification also follows the consensus. However, within Zhang Zhongjing's complete works, the method of determining diseases based on the four seasons and eight solar terms is the outline of the entire *Shanghan Lun*. Recent books have omitted this entirely, except for authoritative texts like Li Zhongzi's works which still retain the main text. Cheng Wuji did not annotate this part either. I have carefully explained it to show how the Big Dipper's position indicates seasonal climatic shifts. When treating cold damage during these times, physicians must formulate prescriptions according to the seasonal climate to achieve perfect results. Hence, Zhang Zhongjing said, "This requires profound understanding."

10. Since Cheng Wuji's annotation, famous Ming dynasty physicians like Li Dongyuan only briefly mentioned treatment essentials, and Zhu Danxi only raised questions on doubtful points. No one had fully interpreted Zhang Zhongjing's original treatise until Fang Zhongxing, a person from Shexian in the late Ming, wrote *Shanghan Tiaobian* (Differentiated Analysis of Cold Damage) in eight volumes, becoming a significant figure after Cheng Wuji. In the early Qing dynasty, Yu Jiayan expanded on Fang's unelaborated points, writing *Shanglun Pian* (Essays on Ancient Discussions) in five volumes, making him another merit-maker for Zhang Zhongjing. Cheng Jiaoqian followed the intent of these two books to write *Hou Tiaobian* (Subsequent Differentiated Analysis) in six collections, which also has valuable content. The regrettable aspect is that all three authors disrupted the original order of Zhang Zhongjing's Six Chapters. Although each had their theoretical focus on the Six Channels, the original order might reflect Wang Shuhe's incomplete editing, where Zhang's subtle meanings could have been lost due to these new compilations. Furthermore, medical formula books aim to clarify each point to prevent medical errors, rather than adhering strictly to literary continuity as Confucius advised preserving ritual even at the cost of a sheep. Regarding the original order of the Six Channels, I dare not disrupt Wang Shuhe's established structure.

11. In Zhang Zhongjing's Six Chapters, if something previously attached must be moved later, or vice versa, it is called the "Fu Li" (Appendix Rule). If something already annotated appears again in the original text, it is called the "Chong Chu Li" (Repetition Rule). If something mentioned initially in the original text has not yet been annotated and should be appended later, it is called the "Fu Hou Li" (Append Later Rule). Other cases, such as Warm Disease (Wen Bing), Ruined Disease (Huai Bing), and conditions requiring acupuncture, are treated separately in subsequent chapters. Formulas suitable for appendix are handled similarly. Among the Six Chapters, only Cold Syndrome (Zhong Han) represents True Yin Syndrome and is not subject to the above rules, but marked with double circles. True Yin-Cold conditions requiring decoctions are also marked with double circles.

12. Whenever Zhang Zhongjing's discourse or Cheng's annotation is deemed inappropriate in this book, I occasionally cite views from Fang Zhongxing, Yu Jiayan, Cheng Jiaoqian, and other masters. I do not steal their works or names but explicitly attribute them. Occasionally adding my own thoughts, I use the phrase "Yu An" (Humble Commentary); or I set up hypothetical questions and answer them myself.

13. Since this book collects Zhang Zhongjing's discourses, it necessarily appends formulas and discussions from past sages and later generations. These interpretations are my own, clarified item by item. I extensively cite evidence and dare not create private theories, ensuring that discussions are logical and formulas match the disease. I earnestly hope that anyone who reads this book, even when encountering strange variations of cold damage, will find effective treatment methods. Can practitioners not strive for this?