The energy of the Dantians has two polarities; the lower Dantian is the Yang (陽) side, and the upper Dantian is the Yin (陰) side. The two polarities regulate the whole energy system of the body.
The Yang side supplies the quantity, while the Yin side supplies the quality. The quality of the energy will improve as the practitioner learns how to focus better. However, it is not a task that can be finished since there are unlimited levels of focus. Only through practice can you attempt to achieve a level of focus where outside distractions will not register. To improve the quantity, you have to condition the lower Dantian. For further information please refer to the book Qigong, The Secret of Youth—Da Mo's Muscle/Tendon Changing and Marrow/Brain Washing Classics, by Dr. Yang, Jwing-Ming. Click to learn how Chinese medicine treats Fatty Liver.