"The congenital base lies in the kidney and the postnatal base in the spleen." The nutritional essence coming from the two zang organs of the spleen and kidney is the motive power of the visceral functions of the whole human body. Thus, the concept of healthy qi as the base should first be aim at the two zang organs of the spleen and kidney.

Reinforcing essence and qi is the key to the tonification of the kidney, and strengthening transportation and transformation is the key to enhancement of the spleen, both of which promote and supplement mutually. Of all activities of life cultivation and rehabilitation, the conservation and promotion of functions of the spleen and kidney are the important content which cannot be ignored. More information, please read Physiological Functions of Qi.