Wuji (無極) is a state of emptiness or simply a single point in space. There is no discrimination and there are no polarities (or poles). One possible example is the state of the universe before the big bang, a point of singularity. According to Yi Jing (i.e., Book of Change), originally the universe was in a Wuji state. Later, due to the pivotal action of Taiji, Two Polarities (Liang Yi, 兩儀) (i.e., Yin and Yang) were discriminated. However, we should understand that Yin and Yang are not definite (or absolute) but relative according to specifically defined rules. From these rules, Four Phases (Si Xiang, 四像) are again derived. From different perspectives, the Yin-Yang two polarities can again be divided into Yin and Yang. For example, if you use your right hand to follow the Yin and Yang pattern, the clockwise cycling belongs to Yang while the counterclockwise cycling belongs to Yin.
Generally speaking, your right hand action is classified as Yang and your left hand action is classified as Yin. From this rule, the Yin-Yang cycling will be completely reversed if you use your left hand. These general rules are applied in Taijiquan and also in other internal styles such as Baguazhang. The above saying is talking about the Yin-YangÕs derivation in two dimensions. When this Yin-Yang derivation is manifested in three dimensions, then right spiral to advance forward is classified as Yang while left spiral to withdraw is classified as Yin. Similarly, the manifestation of the left hand is reversed.
From this, we can see that (if we are) able to comprehend the theory of great nature's Yin-Yang spiral derivation, then (we) will be able to comprehend the function of the Dao and use this Dao to understand the theory of ceaseless recycling of millions of lives in nature, furthermore, to trace back the origin of our human and physical life. The purpose of learning Taijiquan is to aim for the comprehension of Taiji and Yin-Yang so (we) are able to reach the Dao, therefore, (allows us) to protect (our body), strengthen (our body), and enjoy longevity.
Furthermore, by nourishing and cultivating (our) human nature, (we are) able to reach the final goal of unification of heaven and human spirit. From the above discussion, you can see that there are some specific rules that apply when you manifest the Yin-Yang polarities into two dimensions. However, we exist in a universe of at least three dimensions. Therefore, the concept of two polarities should be adapted to three dimensions so we can comprehend the natural Dao thoroughly. Once you add the third dimension to the Yin and Yang symbols, you can see that the energy patterns and derivation are spiral actions.
When the nature loses its balance, the energy manifests in spirals and millions of lives are influenced, or even are created. All of these manifestations can be seen from galaxies in space, to tornados and other storms, to the formation of sea shells, and even the tiny, twisted strands of our DNA. From the above discussion, you can see that when Yin-Yang is manifested in two dimensions in Taijiquan, it is an action of coiling, and when it is acting in three dimensions, it is a spiraling maneuver. If you use your right hand to generate this spiral motion, then the clockwise and forward motion is classified as Yang while the counterclockwise and backward motion is classified as Yin. If you use your left hand, since the left is classified as Yin, all directions are reversed.
This is a method to practice the basic skills in Taijiquan for changing from insubstantial to substantial and back again. All action in Taijiquan originates from the Real Dan Tian (a point, center of gravity), where the Wuji is located. From this Wuji center, through Taiji (i.e., mind) the Qi is led, Yin and Yang spiraling actions are initiated, and Taijiquan movements are derived.
This article is based on the book "Taijiquan Theory of Dr. Yang, Jwing-Ming".