The liver is the seat of the soul, the storage of blood, and the organ of tendons; it belongs to wood in the Five Elements, thus its color is green. The spleen is the source of the generation and transformation of qi and blood, the foundation of acquired life, and the place where intent is stored; it belongs to earth in the Five Elements, so its color is yellow.
The lungs are the residence of the corporeal soul, the master of qi, and belong to metal in the Five Elements, which is why they are white in color. The kidneys are the foundation of congenital essence, the storage of will, with the waist being the associated organ; they belong to water in the Five Elements, denoting the color black.
When the colors inside the five organs and six bowels undergo change, it signifies that the person has an illness. For instance, in the location of the heart, should there be pathological changes, the color will shift accordingly.
