The energy "Chi" is balanced between two forces: the yin and the yang.
In the Chinese philosophy there are two forces in balance, two dynamic and complementary polarities (as(like) to breathe: to inhale to expire, one cannot exist without other one) The interaction of these two forces they produce the changes that the world supports in movement. The symbol of the yin and the yang is very powerful. They are two opposite and complementary forces that they find in constant movement. The clear and dark form they show that when the darkness diminishes the light.