Qi of viscera and bowels are started from their viscera and bowels and runs into distribution areas of main meridian along main meridian and supports organism of administration areas of main meridian. Qi of viscera and bowels are formed lesser circulation by meridians in internal and external relation, it enters from yin to yang and from yang to yin and this lesser circulation is called "six combinations" in circulation of meridians and collaterals. It runs into other viscera and bowels and meridians and collaterals through distribution of meridians and collaterals and plays the role of coordination of qi transformation.