既知五官分五脏。当知五色分五脏。盖人者。天地之心也。五行之端也。食味别声。被色而生者也。故经云。
以五色命脏。青为肝。赤为心。黄为脾。白为肺。黑为肾。肝合筋。心合脉。脾合肉。肺合皮。肾合骨。故青病在筋。
赤病在脉。黄病在肉。白病在皮。黑病在骨。盖以色应脏。以脏合形也。然或察部以言脏。或察色以言脏。亦
犹诊脉之法。或以气口寸关尺分五脏。或以弦钩代毛石分五脏。夫弦钩代毛石者。五脏之气。见于血脉
也。青赤黄白黑者。五脏之气。见于气色也。五脏之气。见于气色。因以气色分五脏。五脏之气。见于明堂。因
以明堂分五脏。此活法也。亦定法也。至若以气色分脏腑。则浮泽为外。病当属腑。沉浊为内。病当属脏。若
更合气色部位分脏腑。则色见于脏部者。其色深浓。当为脏气有余之病。其色浅淡。当为脏气不足之病。
见于腑部者。其色深浓。当为腑气有余之病。其色浅淡。当为腑气不足之病。故以阴阳言。则脏阴也。腑阳
也。色见诸阴者。脏病也。见诸阳者。腑病也。察其何部何色。而断其何脏何腑也。举凡皮肉血脉筋骨。亦以
气色部位分之。矧气色有阴阳。部位有阴阳。脏腑病症。又各有阴阳。参而伍之。错而综之。可以象求。难以
数推矣。
既然知道了五官分别对应五脏，就应当知道五色也分别对应五脏。人，是天地的心智所在，也是五行的开端。人通过饮食味道辨别声音，凭借肤色而生存。所以医经说：用五色来命名五脏，青色对应肝，赤色对应心，黄色对应脾，白色对应肺，黑色对应肾。肝与筋相合，心与脉相合，脾与肉相合，肺与皮相合，肾与骨相合。因此，青色病变在筋，赤色病变在脉，黄色病变在肉，白色病变在皮，黑色病变在骨。这是因为以颜色对应脏腑，以脏腑对应形体组织。然而，有时通过观察面部部位来推断脏腑，有时通过观察气色来推断脏腑，这也如同诊脉的方法一样，有的通过气口寸、关、尺三部来区分五脏，有的通过弦、钩、代、毛、石五种脉象来区分五脏。所谓弦、钩、代、毛、石，是五脏之气显现于血脉之中；青、赤、黄、白、黑五色，是五脏之气显现于面部气色之中。五脏之气显现于面部气色，因此依据气色来区分五脏；五脏之气显现于明堂（鼻部），因此依据明堂的部位来区分五脏。这是灵活运用的方法，也是固定的法则。至于通过气色来区分脏腑，则色泽浮露润泽的属于外，病证归属于腑；色泽深沉浑浊的属于内，病证归属于脏。如果再结合气色的部位来区分脏腑，那么颜色出现在脏部位置的，如果颜色深浓，应当是脏气有余的病证；如果颜色浅淡，应当是脏气不足的病证。出现在腑部位置的，如果颜色深浓，应当是腑气有余的病证；如果颜色浅淡，应当是腑气不足的病证。所以从阴阳的角度来说，脏属阴，腑属阳。颜色显现于诸阴部位的，是脏病；显现于诸阳部位的，是腑病。观察是哪个部位、哪种颜色，从而判断是哪个脏、哪个腑的病证。举凡皮、肉、脉、血、筋、骨，也都依据气色和部位来划分。况且气色有阴阳之分，部位有阴阳之分，脏腑病症又各有阴阳属性。将这些因素参互比较，交错综合，可以通过取象比类来推求，却难以用简单的数理来推算。
Having understood that the five orifices correspond to the five Zang organs, one must also understand that the five colors correspond to the five Zang organs. Humans are the mind of Heaven and Earth and the beginning of the Five Elements (Wu Xing). Humans distinguish flavors by taste, perceive sounds, and exist through their complexion. Therefore, the Classics state: Assign names to the Zang organs based on the five colors: Green corresponds to the Liver, Red to the Heart, Yellow to the Spleen, White to the Lung, and Black to the Kidney. The Liver harmonizes with the tendons, the Heart with the vessels, the Spleen with the flesh, the Lung with the skin, and the Kidney with the bones. Thus, green indicates pathology in the tendons; red indicates pathology in the vessels; yellow indicates pathology in the flesh; white indicates pathology in the skin; black indicates pathology in the bones. This is because color corresponds to the Zang organs, and the Zang organs correspond to the physical forms. However, sometimes one infers the Zang organs by observing facial regions, and sometimes by observing the complexion. This is similar to pulse diagnosis methods, where some differentiate the five Zang organs using the Cun, Guan, and Chi positions at the Qi Kou (radial artery), while others use the string-like (Xian), hook-like (Gou), intermittent (Dai), floating-like (Mao), and stone-like (Shi) pulse qualities to differentiate them. The string-like, hook-like, intermittent, floating-like, and stone-like pulses represent the Qi of the five Zang organs manifesting in the blood vessels. The five colors—green, red, yellow, white, and black—represent the Qi of the five Zang organs manifesting in the facial complexion. Since the Qi of the five Zang organs manifests in the facial complexion, one differentiates the Zang organs based on the complexion. Since the Qi of the five Zang organs manifests in the Ming Tang (the nose area), one differentiates the Zang organs based on the regions of the Ming Tang. This is both a flexible method and a fixed rule. Regarding the differentiation of Zang and Fu organs by complexion, a floating and lustrous appearance indicates an exterior condition, attributing the disease to the Fu organs; a deep and turbid appearance indicates an interior condition, attributing the disease to the Zang organs. Furthermore, if one combines the location of the complexion with the differentiation of Zang and Fu organs, then when a color appears in a Zang region: if the color is deep and concentrated, it indicates a disease of excess Qi in the Zang organ; if the color is light and pale, it indicates a disease of deficient Qi in the Zang organ. When a color appears in a Fu region: if the color is deep and concentrated, it indicates a disease of excess Qi in the Fu organ; if the color is light and pale, it indicates a disease of deficient Qi in the Fu organ. Therefore, speaking from the perspective of Yin and Yang, the Zang organs are Yin, and the Fu organs are Yang. Colors appearing in the various Yin regions indicate Zang diseases; those appearing in the various Yang regions indicate Fu diseases. By observing which region and which color appear, one can determine which Zang or Fu organ is affected. Generally, the skin, flesh, vessels, blood, tendons, and bones are also differentiated according to the locations and complexions. Moreover, since complexions have Yin and Yang aspects, regions have Yin and Yang aspects, and Zang and Fu pathologies each possess Yin and Yang attributes, these factors must be compared and integrated. One can seek understanding through analogical reasoning (Xiang Qiu), but it is difficult to deduce through mere numerical calculation.