岳飛二要論/Yue Fei Er Yao Lun – Yue Fei’s Second Essential Thesis

嘗有世之論捶者，而兼論氣者矣，夫氣主于一，可分為二，所謂二者，即呼吸也，呼吸即陰陽也，捶不能無動靜，氣不能無呼吸，吸則為陰，呼則為陽，主呼靜者為陰，主乎動者為陽，上升為陽，下降為陰，陽氣上升而為陽，陽氣下行而為陰，陰氣下行而為陰，陰氣上行而為陽，此陰陽之分也，何為清濁，升而上者為所清，降而下者為濁，清氣上升，濁氣下降，清者為陽，濁者為陰，而要之陽以滋陰，渾而言之，統為氣，分而言之為陰陽，氣不能無陰陽，即所謂人不能無動靜，鼻不能無呼吸，口不能無出入，此即對待循環不易之理也，然則氣分為二，而實在于一，有志于斯途者，慎勿以是為拘拘焉。

There have always been those who discuss boxing without discussing Qi, too. Though Qi is mastered whole, two types may be distinguished, namely “Exhalation & Inhalation.” Exhale & Inhale are also called Yin & Yang. Boxing cannot lack moving & stillness, Qi cannot lack exhaling & inhaling. Inhaling is Yin, exhaling is Yang, Yin is the master of stillness, Yang is the master of movement, Rising is Yang, Falling is Yin. Yang Qi ascends & becomes Yang, Yang Qi descends & becomes Yin. Yin Qi descends & becomes Yin, Yin Qi ascends & becomes Yang. This Yin Yang can also be divided. What is meant by “Clear & Turbid?” Rising & ascending are “Clear,” dropping & descending are “Turbid.” Clear Qi rises up, Turbid Qi sinks down. Clear is Yang, Turbid is Yin, & essentially, Yang nourishes Yin. When combined, its united as “Qi,” when divided it becomes “Yin Yang.” Qi cannot lack Yin & Yang, what are called people cannot lack movement & stillness. The nose cannot lack exhaling & inhaling, the mouth cannot lack exiting & entering. While this discusses the unchanging natural cycle, it is also scientific. That being the case, while Qi can be subdivided into two, in reality it is one. Those who are determined to study must be careful not to restrict this theory.