This is a weighty topic. When students first encounter the bones, they laugh. Bones don't make sense. I say:
"Bone Training is weird. You enter a strange and uncertain place. With gravity there is no Yin/Yang. How could there be when gravity does not vary? To separate meat from bones requires great and sustained efforts of mental transformation. Your body's state of bony separation never varies. Our expectations are what varies. At this time, to perceive bony cues is virtually impossible."
I have developed the Mental Models so that these perceptual changes are clear and inevitable. One leads to the next and the next contains the previous. Very difficult, but worth the effort. Initially, practitioners must notice that a heavy mind, such as in those who cultivate gravitas, is exactly the opposite of the lightness of mind required to separate bones and meat. If you find yourself in a grim and serious state regarding your NeiJia practice, stop it. Progressing requires that you walk the finest of lines between great effort and lightness of mind. On the other side of Bone Training you will see that the line is not fine at all.
As for a concrete training methodology, there are several requirements during practice. What movement you choose doesn't matter, although certain movements help. In order of dependency:
- Clearly distinguish Shen. ( Refined Warrior Spirit ) from Yi. This takes some meditative work, but with the Standing Mental Model it becomes clear that these feelings arise from different sensory networks. Confusing the two leads to 'Heavy Yi and Wild Qi'. In general, this means do not strive for any positive outcome. Notice the interactions between Shen and Yi->Qi. Avoid anything that imparts Heavy-ness.
- Be intentional. Intentional learning in this context means your expectations govern outcomes. This is the most difficult aspect to understand.
- Mind the Slack. By maintaining slack as the object of your moving mediation, you are cultivating the mental model and movement primitive that together stimulate the deep sensory networks needed to condition the tissues to clearly perceive that the bones and meat are already separate. This reinforces the Yi.
The separation of bones and meat realization comes first, then, over time, the new perceptions become part of 'everyday and ordinary' movement. There is huge change in the type of training a student can perform after the change in Yi that supports Separate Bones and Meat. For example, certain extremely twisty NeiGong shapes that, before the change in Yi, constrict the breath and range of movement, while the same movement performed after, the breath is free and range of movement increased. Then we play with the different expectations and notice the effect on the breath in the same twisty postures. After a month or so, the Heavy Yi and Light Yi difference begins to become clear. In this method, the Heavy Yi and Light Yi perception is required to directly access the bones. This is very different than indirectly accessing the bones by way of the 'meat reference'. 'Softness into hardness' as a deliberate training process is dependent on this change in perception.