It was supported by the concept that in areas which are not directly controlled by an emperor of China such as the second or third categories above, the virtue of an emperor of China lost influence, and the power of control of China decreases accordingly.
前者から後者に行くに従い、漸次中国皇帝の徳が及ばなくなり、同時に中国の支配力も低下していくという観念で支えられている。