Nei Jing

In advanced traditional Chinese kung fu (martial arts), Neijing (Traditional Chinese: ; pinyin: nèijìng) refers to the conscious control of the practitioner's qi, or "life energy", to gain advantages in combat. Nèijìng is developed by using "Neigong" (Traditional Chinese: 內功; pinyin: nèigōng) (), or "internal exercises," as opposed to "wàigōng" (), "external exercises."

Practitioners of kung fu refer to two separate forms of personal force: Li (Traditional Chinese: 力) refers to the more elementary use of tangible physical (or "external") force, such as that produced by muscles. Neijing (Traditional Chinese:內勁) or Neigong (Traditional Chinese: 內功), in contrast, refer to "internal" forces produced via advanced mental control over psychic energy (the qi).

The degree of Li force one can employ in kung fu depends on several variables such as resilience of muscles, strength of bones, speed and timing of attack and so on. An effective way to enhance the Li force is to exercise one’s muscles and bones by applying increasing pressure on them (weight training, gym exercises, etc.). The stronger one’s muscles and bones become, the more powerful and skillful the level of kung fu is.

On the other hand, the level of the Neijing force depends on the extent one can exercise one’s will power to release an inner qi energy. Within the framework of Chinese martial arts, every person is believed to possess the inborn energy of qi. Martial artists can harness the force of qi so that it is strong enough to be applied in combat. When qi is being directed by one’s will, it is called Neijing.

The Li force is observable when it is employed. Unlike the Li force, Neijing is said to be invisible. The "pivot point" essential to Li combat is not necessary in Neijing. At the point of attack, one must ‘song’ (loosen) himself to generate all Neijing energy one possesses and direct this energy stream through one’s contact point with an opponent. The contact point only represents the gateway to conduct Neijing energy at the point of attack.

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Wikipedia