This follows the preceding text. After Huoluan (cholera-like syndrome with vomiting and diarrhea) and purging, the loss of body fluids leads to dry stool. If the stool is dry but the patient can eat, it indicates recovery; this belongs to the harmonization of Stomach Qi in the Yangming stage. Now, conversely, if the patient cannot eat, it means the pathogen has transmitted to the subsequent channel. If the ability to eat returns later, it implies that another channel cycle has passed before eating resumed. If this belonged to the harmonization of Yangming Stomach Qi, it should have healed after passing one day. If it does not heal, the sudden fever enabling eating is not due to the harmonization of Yangming Stomach Qi. This generally refers to the concept of "passing a channel" (Guojing). Where is there any principle that "transmitting again through a channel" is called "passing a channel"? Moreover, how could pathogenic factors transmit through the Six Channels three times? Cheng Wuji's commentary on Zhang Zhongjing's works elucidates profound principles and benefits future generations greatly. However, his understanding of channel transmission is insufficient, leading to forced interpretations. *Yizong Jinjian: Summary of Essential Principles* follows Cheng's commentary. In the example of "pathogen remaining after passing a channel," it states: "The classic says 'Shanghan for thirteen days without resolution is called Guojing.' Does Zhang Zhongjing say this? Therefore, Cheng's commentary is treated as canonical." In his "Discussion on Six-Channel Transmission," he further states: "If Guojing is not resolved, it becomes a damaged disease (Huai Bing)." The so-called "damaged disease" mentioned by Zhang Zhongjing refers to damage caused by improper treatment. The view in *Yiyao* is an error compounded by error. Tao Shangwen said: "Shanghan that does not resolve after sweating and passes a channel, with symptoms persisting, is also a Warm Disease (Wenbing)." This explanation is even more incomprehensible.

Wei Litong said: Min's theory on channel transmission can independently reveal subtle meanings. His theory that "after transmitting through all six channels, it does not transmit again" is actually based on the *Neijing*, specifically the principle that "pathogens transmit sequentially to one Zang organ and do not injure two; injuring two leads to death." His crucial point is that when discussing Shanghan channel transmission, the mention of "days" should not be rigidly confined to specific numbers. This is particularly incisive. However, some points need clarification. The classic says, "On the first day, the Taiyang receives the pathogen," merely indicating that Taiyang disease begins on that day. Even if Taiyang disease persists for dozens of days, it can still be considered within the initial phase of Taiyang. Thus, there are cases where life and death are determined entirely within the Taiyang stage. Zhang Zhongjing established the special chapter on "pathogen remaining after passing a channel" precisely to explain cases where Shanghan does not transmit. "On the second day, the Yangming receives the pathogen" simply marks the beginning of transmission from Taiyang to Yangming. If the stay in Taiyang is short, we call it transmission to Yangming, which is naturally the second day of Yangming. If the stay in Taiyang is long, taking seven or eight days to transmit to Yangming, it is still referred to as the second day of Yangming. The same logic applies to the sequential mentions of the third, fourth, fifth, and sixth days for other channels. The mention of "seven days" serves to calculate from the initial reception in Taiyang until its resolution on the seventh day, using days to clarify the sequence of transmission. It is like traveling from here to a destination: a seven-day journey's duration depends on speed and arrival time, which cannot be fixed. This is the meaning behind "Taiyang disease should resolve on the seventh day." Min regarded this as referring to Shaoyang, which seems too literal. I believe considering the day of Taiyang resolution as the seventh day is clearer. Any day Yangming receives the pathogen is called the second day, marking the sequence of initial transmission from Taiyang. Whether the stay in Yangming is long or short, the day of resolution is the eighth day. There is no need to associate seven days with Shaoyang numerology. The resolution days for other channels follow this pattern. Although this seems inconsistent with the literal text, it deeply aligns with the essence of the classic. Why? The classic presents eternal laws to the world, perhaps necessitating the use of days to clarify sequence, allowing people to understand the chronology of Six-Channel disease and resolution. In reality, pathogenic changes are sudden and unpredictable; aggravation or resolution has no fixed timing. This applies to all diseases, especially Shanghan. How can they be calculated by days? Therefore, Zhang Zhongjing established chapters on Combined Diseases (He Bing), where if two or three channels are affected simultaneously, the division of the Three Yang channels is filled in one day, making daily calculation irrelevant. Even Cold pathogens directly invading the Yin channels may affect all Three Yin channels at onset. Why must Taiyang be affected on day one, Shaoyin on day two, and Jueyin on day three? Cold pathogens often directly invade Shaoyin because Yin originates from below, and the Kidney meridian is in the lower body. Direct invasion of Shaoyin often involves all Three Yin channels, with simultaneous Shaoyin and Jueyin involvement being common. Can this be calculated by days? (Shen Jin'ao notes: Not only is direct invasion of Shaoyin and Jueyin common, but transmission to Shaoyin often immediately proceeds to Jueyin. Symptoms of these two channels often appear within half a day because Liver and Kidney share the same region and easily influence each other.) Knowing to discuss channels by days, yet examining disease without being bound by days, allows one to truly discuss treating according to the classics. When pathogenic factors enter Jueyin and it is claimed they re-transmit to Taiyang, searching the *Lingshu* and *Suwen* and examining Zhang Zhongjing's discussions reveals no such statement. Anyone with basic medical knowledge can see this as absurd. Physically, internally connecting Zang-Fu organs and externally connecting meridians, there is no pathway for pathogens to enter Taiyang from Jueyin. If pathogens have penetrated the exterior, they ascend and dissipate; how could they move from interior to exterior and then back to interior? Ask yourself: throughout history, who has treated Shanghan where pathogens moved from Jueyin back to Taiyang? In my observation, modern patients with Shanghan in the Three Yang channels decide life or death quickly. Direct invasion of Yin channels occurs. Transmission to Yin channels is rare. Transmission through all six channels is even rarer. Since most people today have weak constitutions and many physicians lack clear skills, patients die before transmission completes. Thus, seeing Shanghan that has transmitted through all six channels is non-existent. (Shen Jin'ao notes: This argument is precise and rapid, serving as a reminder to contemporary physicians.) Moreover, although Shanghan is distinguished into six channels, patients do not always present with strict boundaries. At onset, simultaneous involvement of two or three channels is common. Transmission from one area to another while unaffected areas remain intact is frequent. Yang channel diseases may enter Yin channels. Simultaneous Taiyang and Shaoyang involvement is seen. Simultaneous involvement of all Three Yin channels is also observed. Therefore, Zhang Zhongjing established chapters on Combined Diseases (He Bing) to discuss pathology and Concurrent Diseases (Bing Bing) to discuss treatment. Although Combined and Concurrent diseases are discussed primarily regarding the Three Yang, this is merely an example; one should infer the rest. Without such inference, books piled high would be useless. With spiritual comprehension, one will find resonance in these words.

Shen Jin'ao notes: Since Zhang Zhongjing discussed channel transmission, debates have been endless, ultimately failing to align with the classic's intent because everyone was bound by day counts, leading to fragmented arguments. Since Min clarified the logic beforehand and Wei elaborated afterwards, combining these two perspectives provides a definitive case for channel transmission for eternity. It is indeed a secret manual for the Shanghan specialty.