Can anyone help me with this? Is this the posture difference that is discussed between Bagua Quan and Bagua Zhang?
Yes, although it is as always a subject that easily argued and not easily picked apart because it's kind of an experiential thing.
Suffice it say, the body mechanics are better described by where the force is generated and led by the postures rather than what would be easily assumed by the shape of things...if that makes any sense. I wish there was a drawing program that where I could easily make some diagrams around a human form to try and show how the forces are at work.
So anyway, the initial aspects of training the body method are pretty much backwards from the way most people do it, and while I assume the end result should be the same for both ways (i.e. a completely open where you are able to put your mind wherever you want to without feedback from the body impeding your will in any fashion) the way we do it and the way most people do it emphasizes different qualities initially and have different strengths and weaknesses.
The way it's different from how I've felt it in my body is that the "turtle back" way that most people do it moving the energy up the back and down the front initially tries to focus the mind on where the sensory apparatus is not normally focused..that is the back, and because the it is difficult to put your mind there when you haven't yet gone through the process the mental connection tends to work from the outside in...kind of like a cloak over the back of your body. It makes for a strong initial connection that creates strong root.
The way we do it starts from where the sense apparatus is already working to a degree, and so I liken it to having saran wrap pulled over the front of your body rather than a cloak on the back of it. The deep twisting starting from the front where you already have a deeper sense the inside of your body takes the mind more towards the center internally faster. There is less emphasis on using the external connection to create a unified root and more emphasis on using the using the deep internal connection to create a stronger sense of structure that can be maintained when root or contact with the ground is lost. Because most of the deep energetic forces are interacting deep within the body to affect how the structure balances itself it is less obvious how the mechanics work. That's why there is less emphasis on the obvious straight up and down with relation to the spine posturally. The spine is straight, but the need to have it completely vertical is negated or made less necessary by what's going on inside. I actually hate to say it but some of crazy ole Happehs models of this are pretty good regardless of how out of his mind he is in general.
Anyhoo, Master He is the expert. I can only reference these things on what's gone on in my body the last 6 or so years I've been doing this, so I'd listen to what he says.
It's just a different way of doing things with different benefits. Our way is good to go with lightness skills since there is less emphasis on rooting on the ground...it's just different.
Best,
S