Tai Yi Wu Xing Quan (太乙五行拳) or Tai Yi Five Direction Fist, is referred to as a Liang Yi form. TaiYi is part of the complete TaiJi System with a slight variation is training direction. While a TaiJi form stays within the balance of Yin and Yang, the TaiYi form is more about the distinction and therefore the separation of Yin and Yang. The coordination that internalizes and represents this idea and puts it into action is Fa Jin (發勁). Fa Jin is a special movement characterized by explosive and precise striking. Most often these strikes are done to vulnerable and weak points on the opponents body.
Using the foundations laid down through basic training and a comprehensive TaiJi understanding, the goal to develop Fa Jin power within our system starts from the outside and works in. That is to say that the outside coordination must be very clear and efficient in order to establish proper posture during Fa Jin movements.
The system of thought follows the philosophy of Daoism. Two special terms explain this characterization, Ming (命) and Xing (性). These two concepts are interrelated and essential to the nature of all livign things. To simplify the realm of each we can say that the Ming refers to our living path or of natural existence. This is closely tied into our longevity and therefore our health. Xing refers more to our individual nature, character, or even our personality. This is an oversimplification as the terms themselves each encompass a large range of attributes and qualities. For the sake of our explanation here, they can serve as the material with which we live in the natural world (ming) and the force that drives and fulfills the accomplishments of such a vessel (xing). For the practice of TaiJi, Tai,Yi, Fa Jin, and all martial arts in general, the practice begins by coordinating the external realms and slowly bringing that awareness deeper into ourselves. Eventually the practice becomes a metaphor for all of the philosophy and morality that is the foundation of Daoism.
The dual cultivation of our Ming and our Xing is a key value system in Daoist internal training. The training of our body becomes more fluid, well coordinated, soft when yielding, and explosive when striking. All movements begin after the opponent has started their own offense and finish before the opponent technique is achieved. This is the essence of TaiYi. A balance of harmonized movement that is perpetually ready to strike by using the most efficient path.