A person's muscles and bones become externally tempered and internally fortified through practice, becoming integrated where a single exertion harmonizes the use of the entire body, capable of emitting the Tiger and Leopard Thunder Sound—that is the initial achievement of Hua Jin.
Further on, at the stage of great success of Hua Jin, every part of the body reacts when stimulated, achieving "not a feather can be added, nor can a fly land"—meaning any part of the body that is touched can instantly react, bursting out with Thunder Sound and shaking the body.
And if one progresses further to refine all muscles, bones, and flesh of the body like a tuning fork, it reaches the realm of Innate Gang Qi.
In the virtual reality, Wu stood in a Three Body Formation; then, he opened his mouth and uttered "Hmm." His body slightly vibrated, and a deep humming sound emerged from within him.
