What is "Jin" in traditional martial arts? How can I develop "Jin"?

Jin in traditional martial arts refers to the combination of body structure mechanics, muscle strength, bone mechanics, internal organs and other forces. The first principle is that the organs of the body do not inhibit each other and are not internally consumed (i.e., no stiffness, no breath-holding); it is characterized by the conduction of power, which is different from the power of bodybuilding and lifting heavy weights, i.e., it focuses more on the penetration of power, and does not require brute force and cart power.

The method of practicing 'jin' is systematized and consists of: standing stakes, routines, single drills, sparring exercises and so on. Entry generally starts with making the body smooth, and progresses to understanding what jin is, to practicing jin, to using jin, and finally to the practical stage.

I hope the above answer can help you.