Library

For external pathogenic factors (Wai Xie) attacking the exterior, one should discuss solely based on the site of the pathogen's invasion, without necessarily involving the disturbance of internal Zang-organ Qi. Even if the disease persists for a long time and the Zang-organ Qi is disturbed and burdened, the primary focus remains on the site invaded by the pathogen; where the disease lies, there the symptoms manifest, making it easy to identify. However, when Zang-organ Qi is internally injured, the pathology hides within while the manifestations appear externally, each having fixed patterns. If not observed carefully, confusion often arises. Why? Because the external signs corresponding to the Five Zang organs are often similar, making it difficult to adhere rigidly to single criteria. Moreover, there are cases involving multiple Zang organs interacting and influencing each other, so differentiation must be pre-established. Summarizing the essentials, there are several aspects: First, the sites traversed by the meridians, such as the Taiyang (Greater Yang) and Shaoyin (Lesser Yin) meridians running along the posterior body, the Yangming (Bright Yang) and Taiyin (Greater Yin) meridians running along the anterior body, and the Shaoyang (Lesser Yang) and Jueyin (Terminal Yin) meridians running along the lateral body. Second, the sites nourished by Qi transformation, such as the Spleen governing the four limbs and lips, the Lung governing the nose and shoulder-back, the Liver governing the sinews (Jin), nipples, and eyes, the Kidney governing the two yin openings, waist-spine, and ears, and the Heart governing the face and tongue. Third, the functional roles of Zang-organ Qi, such as the Liver governing dispersion and drainage (Shu Xie), the Heart governing the Spirit (Shen Ming), the Lung governing exhalation, the Kidney governing inhalation (Na Qi), and the Spleen governing the Middle Jiao and regulating the ascending and descending of all Qi. Fourth, the tissues governed by Zang-organ Qi, such as the Liver governing sinews, the Heart governing vessels (Mai), the Spleen governing muscles, the Lung governing skin and hair, and the Kidney governing bones. Fifth, facial colors and their corresponding regions: the five colors are Liver-green, Heart-red, Spleen-yellow, Lung-white, and Kidney-black; the regions are Heart-forehead, Kidney-chin, Spleen-nose tip, Lung-right cheek, Liver-left cheek, as well as the facial color regions described in the *Ling Shu*. By cross-referencing these points, the location of the disease will be revealed without omission. Among these, the functional role of Zang-organ Qi is particularly important, as stated in the classics: "Examine the pathogenesis, do not miss the appropriateness of Qi." By observing the progressive changes in symptoms over several days, one can determine which Zang organ the pathogenesis belongs to, thereby clearly identifying the affected Zang. When the true Qi of any of the Five Zang organs is diseased spontaneously, mutual overcoming (Cheng Ke) invariably occurs. For example, Liver disease overcoming the Spleen, or Spleen deficiency being overcome by the Liver, always presents with symptoms of the initially diseased Zang first, followed by those of the subsequently affected Zang. The *Nei Jing* states: "When Kidney Qi overcomes Heart Qi, the Heart is diseased first, and the Kidney responds accordingly"; this applies to facial colors as well. This is what is meant. Therefore, when examining external contraction diseases, one must understand the nature of the Five Elements and the normal and abnormal variations of their functions; when examining internal injury diseases, one must understand the nature of the Five Zang organs and the normal and abnormal variations of their functions.