经络，经脉、络脉也。上编从皮腠而入于络脉，络脉而入于经脉。故此复有经络之论，论经络之色，有
常有变，所以承上编五色，而补其未尽之义。
黄帝问曰∶夫络脉之见也，其五色各异，青黄赤白黑不同，其故何也？
上编言阳明部中之浮络，其色多青则痛，多黑则痹，黄赤则热，多白则寒，未悉其旨。故帝复问络脉
之见，其五色各异，青黄赤白黑不同，所以承上编而复问也。
岐伯对曰∶经有常色，而络无常变也。
经脉内连腑脏，有五行之常色，而络脉则浮见于外，无有经常，而多变也，无常变，犹言变无常也。
帝曰∶经之常色，何如？
未问浮络之变，先问经色之常。
岐伯曰∶心赤、肺白、肝青、脾黄、肾黑，皆亦应其经脉之色
也。
五脏应五色，如心色赤、肺色白、肝色青、脾色黄、肾色黑，此皆以五脏，而亦应其经脉之色，是为常也。
帝曰∶络之阴阳，亦应其经乎？
帝欲详明络色之变，故问络之阴阳，亦应其经乎？
岐伯曰∶阴络之色应其经，阳络之色变无常。
络有阴阳，阴络在内，内系于经，故阴络之色应其经。阳络在外，外浮于皮，故阳络之色变无常。
随四时而行也，寒多则凝泣。凝泣则青黑，热多则淖泽，淖泽
则黄赤，此皆常色，谓之无病。
泣，音涩。所谓应其经者，随四时而行也。如秋冬寒多，则络脉凝涩，凝涩则色青黑。春夏热多，则
络脉淖泽，淖泽则色黄赤。此皆随四时之常色，故谓之无病。
五色具见者，谓之寒热。
阴络应经，而随四时，则络亦有常色。所谓变无常者，若五色具见者，乃浮络之色，乍青乍黑，乍黄乍
赤。变无经常，则非无病，故谓之寒热。寒热者，或寒或热，变无常也。
帝曰∶善。
络脉经脉，浅深不同，而阴络应其经，阳络变无常，是络脉之中，复有阴阳，帝故善之。
Jingluo (Meridians and Collaterals) refers to Jingmai (Main Meridians) and Luomai (Collaterals). The previous section described pathogens entering from the skin and interstices into the collaterals, and then from the collaterals into the main meridians. Therefore, this section further discusses Jingluo, analyzing the fixed colors and variable colors of the meridians and collaterals, thereby continuing the discussion on the five colors from the previous section and supplementing its incomplete meanings.
The Yellow Emperor asked: When Luomai (Collaterals) are visible, their five colors vary; cyan, yellow, red, white, and black appear differently. What is the reason for this?
The previous section mentioned that in the Yangming region, superficial collaterals appearing mostly cyan indicate pain, mostly black indicate Bi syndrome (obstruction), yellow-red indicates heat, and mostly white indicates cold, but the underlying principle was not fully explained. Thus, the Emperor again inquired about the visibility of Luomai (Collaterals) and the variation of the five colors, continuing the theme of the previous section.
Qibo replied: Jingmai (Main Meridians) have fixed colors, whereas Luomai (Collaterals) do not have fixed variations.
Jingmai (Main Meridians) connect internally with the Zang-Fu organs and possess fixed colors corresponding to the Five Elements. In contrast, Luomai (Collaterals) float visibly on the exterior, lacking constant colors and exhibiting frequent changes. "No fixed variation" means the variations are irregular.
The Emperor asked: What are the fixed colors of the Jingmai (Main Meridians)?
Before asking about the variations of superficial collaterals, the question focuses first on the normal colors of the main meridians.
Qibo said: The Heart corresponds to red, the Lungs to white, the Liver to cyan, the Spleen to yellow, and the Kidneys to black; all these correspond to the colors of their respective Jingmai (Main Meridians).
The Five Zang organs correspond to the five colors: Heart is red, Lungs are white, Liver is cyan, Spleen is yellow, and Kidneys are black. These correspond to the colors of the Jingmai (Main Meridians) based on the Five Zang organs, which constitutes the fixed color.
The Emperor asked: Do the Yin and Yang colors of the Luomai (Collaterals) also correspond to the Jingmai (Main Meridians)?
The Emperor wished to clarify the variations in collateral colors, so he asked whether the Yin and Yang colors of the Luomai (Collaterals) also correspond to the Jingmai (Main Meridians).
Qibo said: The color of Yin Luomai (Yin Collaterals) corresponds to the Jingmai (Main Meridians), while the color of Yang Luomai (Yang Collaterals) varies without fixity.
Luomai (Collaterals) are divided into Yin and Yang. Yin Luomai (Yin Collaterals) are located internally and connect to the Jingmai (Main Meridians); therefore, their color corresponds to the Jingmai (Main Meridians). Yang Luomai (Yang Collaterals) are located externally and float beneath the skin; therefore, their color varies without fixity.
(This variation) follows the four seasons. When cold predominates, the blood flow becomes stagnant and sluggish. Stagnation results in cyan or black colors. When heat predominates, the blood flow becomes moist and lubricated. Lubrication results in yellow or red colors. These are considered normal colors, indicating a state of health.
"Qi" (weeping/stagnating) sounds like "Se" (astringent/sluggish). What is meant by "corresponding to the Jingmai (Main Meridians)" is following the seasonal changes. For instance, in autumn and winter when cold predominates, the Luomai (Collaterals) become stagnant, resulting in cyan or black colors. In spring and summer when heat predominates, the Luomai (Collaterals) become lubricated, resulting in yellow or red colors. These are normal colors following the seasons, hence referred to as disease-free.
If all five colors are simultaneously present, it is termed Cold-Heat syndrome.
Yin Luomai (Yin Collaterals) correspond to the Jingmai (Main Meridians) and follow the seasons, thus having fixed colors. The term "varying without fixity" refers to the case where all five colors appear; this is the color of superficial collaterals, alternating between cyan/black and yellow/red. Such irregular changes indicate pathology, hence termed Cold-Heat syndrome. Cold-Heat syndrome involves alternating cold and heat conditions, characterized by unpredictable variations.
The Emperor said: Excellent.
Luomai (Collaterals) and Jingmai (Main Meridians) differ in depth. Since Yin Luomai (Yin Collaterals) correspond to the Jingmai (Main Meridians) and Yang Luomai (Yang Collaterals) vary without fixity, there is a distinction of Yin and Yang within the Luomai (Collaterals). The Emperor praised this explanation.