Here's a PDF (in Chinese) that explains the different levels/stages/phases of Internal Power:
http://homepage.ntu.edu.tw/~changym01/t ... 0force.pdfThe first stage is learning Ying Jin (Hard Force), second is Jiang-Rou Jin (Rigid Soft Force), 3rd is Song-Chen Jin (Loose Sinking Force), 4th is Qingling Jin (Light and Agile Force), and then finally the highest level is Xuwu Jin (Nothingness Force).
Why Yin Fu Baguazhang is called the Ying Zhang (Hard Palm), is because everyone has to learn and pass beyond this level of internal power, and the easiest way to pass-down/ transmit some of the higher level Jins, to a student, is to do the application on them. Since it's relatively easy to learn through touch, Yin Fu mandated that everyone's first movements in a fight would be using their Ying Jin (Hard Power), if they could win the fight with just Ying Jin, then all the better, but if the opponent was good, then start resorting to one's higher levels of skills. It's just a way to keep the higher level skills of the system a better secret to outsiders. But this also sort of became a motto or demeanor of the whole school- 硬挺 Yingting (endure with all one's will),硬著頭皮 Yingzhetoupi (Summon up courage), 硬殼 Yingke (put on a hard shell - Ma Gui really embraced this idea), 硬氣 Yingqi (firm; unyielding; strong-willed), etc.
Don't yield, unless you have to yield.
So the Snake System is a really high level system of Yin Fu Baguazhang and represents 軟硬兼施 Ruǎnyìngjiānshī (Using a gentle method to hide force; or an iron hand hidden inside a velvet glove).
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