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The Six Channels (Liu Jing) listed in the *Shanghan Lun* (Treatise on Cold Damage) differ from those in the *Suwen: Re Bing Lun* (Plain Questions: Treatise on Febrile Diseases). The *Re Bing Lun* is based on the meridians through which Qi circulates; therefore, the symptoms it describes align with the principles of the *Lingshu: Jing Mai Pian* (Spiritual Pivot: Chapter on Meridians). In contrast, the *Shanghan Lun* is based on the sequence of pathogenic invasion; consequently, the symptoms it describes do not align with the principles of the *Lingshu: Jing Mai Pian*.

According to meridian theory, all three Yang channels (Taiyang, Yangming, Shaoyang) present with headache. Only Yangming begins with aversion to cold. However, Zhang Zhongjing includes these in Taiyang disease and defines Zheng Yangming (True Yangming) by "stomach excess" (Wei Shi - accumulation of heat and dryness in the stomach/intestines). Meridian theory states that lethargy belongs to the Foot-Taiyin Spleen channel, whereas Zhang Zhongjing states that Shaoyin disease manifests as a desire to sleep. Meridian theory attributes thirst with desire to drink, and hunger without ability to eat, to the Foot-Shaoyin Kidney channel, whereas Zhang Zhongjing associates Xiao Ke (Wasting-Thirst/Extreme Thirst) and drinking without desire to eat with Jueyin disease. Such discrepancies are numerous.

Only Shaoyang and Taiyin are relatively close to meridian theory, yet even they differ: Meridian theory links visual impairment (mu bu ming) to the Foot-Shaoyin Kidney channel, while Zhang Zhongjing associates dizziness/blurred vision (mu xuan) with Shaoyang disease. Meridian theory links undigested food in stool (sun xie) to the Foot-Jueyin Liver channel, whereas Zhang Zhongjing categorizes such symptoms under the Three Yin diseases.

The reason for this is that meridian theory divides Yin and Yang merely into two layers of exterior and interior, and further divides them into Three Yin and Three Yang based on the anterior and posterior aspects of the body. Zhang Zhongjing, however, not only divides them into exterior and interior layers but also subdivides the exterior's exterior as Taiyang, the exterior's interior as Shaoyang, the interior's exterior as Taiyin, the interior's interior as Shaoyin, and the deepest interior as Jueyin, with its associated Fu organ being Yangming. His theoretical approach emphasizes progressive depth rather than flat, parallel classification.

Therefore, he lists the Six Channel symptoms from the *Re Bing Lun* only as examples for Shanghan, without directly citing them to head the chapters of the Six Channels. He establishes his own distinct theory because, although the names are the same, the substance differs. The reason the substance differs while the names remain the same is that "Taiyang," etc., are grand terms used since ancient times to record Yin and Yang. The *Suwen: Tian Yuan Ji Da Lun* uses them to record the Six Qi of Heaven; the *Nanjing* uses them to record the Six Jie (solar terms/phases) of the year; the *Maijing* (Pulse Classic), Vol. 5 (Bian Que’s Method) uses them to record the six pulses of a day, and Vol. 10 (Hand Inspection Diagram) uses them to record the six positions of pulse diagnosis; Jing Jin (Sinew Channels) use them to record sinews; Pi Bu (Skin Regions) use them to record collaterals; and Jing Mai (Meridians) use them to record Ying and Wei (Nutritive and Defensive Qi). Zhang Zhongjing adopts these terms to record the relationship between Exterior and Interior, sharing the same underlying logic.

Those who wish to thoroughly understand the Six Channel symptoms of the *Shanghan Lun* should not entangle themselves with the *Lingshu* and *Suwen*, lest they cause confusion.