The internal power

《然天地者，萬物之上下也；左右者，陰陽之道路也》- 黃帝內經 素問 天元紀大論

The Yi Jing 易經 (The Book of Changes) : "The Yijing has a long history within Chinese philosophy. It says that everything starts from nothing (Wu), to become something (Yau). Yau splits into two, Yin and Yang. Yin and Yang become Si Xiang (Four Images) which in turn become Bagua (Eight Trigrams). All this sounds very complicated, but the important thing to grasp is that from nothing came something, and from something small developed something bigger - just like a tree that starts life as a small seed. From a single root come many roots, from a single trunk come many branches. However, no matter how many branches, leaves and fruit there are, they all come from the one trunk and root. They are all connected and follow the same principle. " - Excerpt from "Wing Chun Kung Fu, Traditional Chinese Kung Fu for Self Defence and Health" by Grand Master Ip Chun with Michael Tse