It's my understanding (and I mean that in mostly the intellectual sense) that that is the key. That internal path/connection is what is then strengthened, creating the "steel" aspect, isn't it?
Well, Adam, I probably know even less than you on how to credibly explain, in words, what I'm working on. Again, I don't refer to or use jin, kokyu or ki in my personal efforts to work on this stuff. I appreciate others' use of such terminology, and that it gives a nod to Asian sources for specific concepts and exercises, but for me it's an overlay that's been somewhat confusing. What I do understand are ideas like groundpath, and structure, and awareness, and breath. I'm even beginning to get a faint idea of what "internal connection" means.
That is why I appreciate the pioneering efforts of people like Dan Harden and Mike Sigman, and more recently, Akuzawa Minoru, who emphasize hands-on work and are open to questions about what they are showing and how they do what they do. When I compare the insights and material I've gotten from working in person versus flailing around on the Internet, the difference is huge.
So, back to your question about "soft" practices building the awareness of internal connection, which can then be further strengthened through conditioning that includes "hard" practices. I think that awareness of the internal path and internal connection can also be found in the contrast between working in an area with tension and then working in the area with significantly less tension. For example, in working on finding and maintaining the "juji" or cross in the upper body that Akuzawa teaches about (I use the Aunkai term juji, but I think of it as cross), when I relax somewhat after holding a position with significant tension, the remembered sensation
of that cross remains, and I can "find" it again with much less tension. In that context, I've found alternating relatively "hard" with relatively "soft" degrees of tension to be useful in establishing awareness and the ability to return to a structure or connection.
I agree that there is not a black-and-white categorization for hard and soft, at least for me. That's why I tried to describe it as managing a full spectrum or range of degrees of tension. The more I work with these ideas and practices, the more I think of them in terms of a sophisticated coordination
involving internal connections, rather than "hard" and "soft."
For example, sometimes people interested in internal strength skill talk about getting the large skeletal movers out of the way and working with the frame and deeper core muscles to lessen the overall effort of maintaining a frame and moving the opponent's force through or generating force back out. To me this means becoming aware of and learning to coordinate and control connections, structures and musculature in ways not typically found in conventional, everyday movement and neuromuscular habits (that's why these skills have to be trained, right?). And in that initial step of becoming aware of what is going on inside, I've found alternation of more and less tension in the area being worked to be helpful.
I agree that working primarily with high-tension exercises initially could induce neuromusculature habits that might be counterproductive. I've just found that working with a full range of tension from hard to soft, or tight to loose, can be useful. Now let's see where it leaves me in a year or five.
What about working fast versus slow? Again, I think working in a range of speeds can be interesting. Working slow makes it easier to pay attention, for example, to the coordination from the hips down to the feet and the hips through the shoulders to the hands in different martial movements. Increasing the speed gradually until you're really snapping out, say, a punch can help point out the "breaks" in the series of connections that a beginner like me inevitably has. So I go back to working slow.
Another example comes with deep squats, of the kind a friend who does Russian martial arts introduced me to. Moving quickly and lightly through a deep squat induces less tension for me than squatting slowly through the same full range. But the contrast between fast and slow squats relating to how breath fills and binds connections for me was illuminating. I took that insight over to the Aunkai "tenchijin" (Heaven Earth Man) exercise--which can't be done "fast" and correctly--and got much better awareness of what is happening inside when I do the exercise.
While it's absolutely important to be systematic in order to make progress, a certain degree of playful exploration is helpful too.
I'm working on this material for certain specific personal reasons, and I don't aspire to teach it. You've got much better resources in folks with demonstrated skills and understanding who are out there teaching this.