The Yellow Emperor asked, "What is the reason for the fact that the five colors of the meridians are different - green, yellow, red, white and black?" I am afraid to face the sun: The meridians have a constant color, but the connections are not constant. The day of the Emperor: What are the common colors of the meridians? Qi Bo said: The heart is red, the lungs are white, the liver is green, the spleen is yellow, and the kidneys are black, all of which correspond to the colors of the meridians. Emperor's Day: Does the Yin and Yang of the meridians also conform to the meridians? The color of the Yin meridians corresponds to their meridians, while the color of the Yang meridians changes unpredictably and follows the four seasons. Excessive coldness leads to congealing, which in turn turns bluish-black; excessive heat causes marshalling, which in turn turns yellowish-red. These are all normal colors, which are called being free from illness. When the five colors are present, they are called cold and hot. The emperor said, "Good."