Byron Jacobs just posted the latest in his excellent XingYi primers, this time on the last of the XingYi elements Heng Quan:
Byron got into a discussion on the XingYi Facebook group when asked when he was going to show “an advanced version with the “fajin” motions.”
His reply was so good I’m reposting the whole thing here, with his permission, as I feel the same way and he explained it very nicely:
A: these are Primer videos to get people to understand the basics in order to begin practice, so that’s their purpose, fundamentals. Maybe in future I’ll release some other ones with function and application etc. I would like you to clarify what your are asking for with “an advanced version with fajin motions”?
Q: the shaking motions in your strikes where penetrates internally?
A: A couple of things. Its a misunderstanding to think that Fajin means something like a specific method or something. It simply means to issue force. That is all it meant in the past, and that is all it means today. Its real meaning has been twisted and misunderstood, even more so in the west. In more recent times some strange focus on shaking has come into CMA which is not how things were and definitely this too has been twisted into something that it never was. The Xingyi classics never discuss “shaking” and in fact older generation teachers will admonish you for this telling you overtly shaking makes “power leak” from your target. An example is even quoted from Feng Zhiqiang talking about how Chen Fake taught them “While issuing power the body should be relaxed, but one should be very conscious about so-called “Shaking Power” (Dou Jin). This power has to be focused and not scattered all over the body. The more advanced one is, the smaller the shaking. When we were learning Taijiquan from Chen Fake shaking the body in Fa Li was the greatest taboo to be avoided.”
Good issuing of force is firstly dependent on the correct structure, then the correct method and finally using body mechanics to assist with generating optimal force. This is all covered in those basics, and its the long term practice of these key points I put in those videos that will enable you to develop strong issuing of force. Strong issuing of force penetrates
The Tai Chi Notebook 
Byron’s reply is spot-on and concise, like his excellent video primers on Hebei xingyiquan. The most internally connected and powerful of the IMA practitioners I’ve encountered over the past 20 years (hundreds from around the world, from famous names to deliberately obscure) do not shake and fret in solo demonstration or hands-on application. The best grapplers as well (and there are internal elements to highly-skilled grappling) are smooth pythons with subtle shifts of weight/pressure and strength.
LikeLike