To fulfil the defensive function against the Exogenous Pathogenic Factors, the Regular Channels are coupled accord-ing to the Yang-Yang and Yin-Yin principle, realizing the “Upper-Lower” connections. The pairs of channels are disposed at various depths relative to the skin layers.

1-st level,	Tai Yang:	Bladder and Small Intestine;
2-nd level,	Shao Yang:	Gallbladder and Triple Burner;
3-rd level,	Yang Ming:	Stomach and Large Intestine;
4-th level,	Tai Yin:	Spleen and Lung;
5-th level,	Jue Yin:	Liver and Pericardium;
6-th level,	Shao Yin:	Kidney and Heart;

 

Defensive function is effected by the normal or free circulation of Defensive Qi (Wei Qi) upwards from “Root” to “Knot” points and between the layers from Tai Yang; inside to Shao Yin.

Layer or Level	"Root" Points of the Hand Channels	"Root" Points of the Foot Channels	"Knot" Points
Tai Yang	SI1 (Shoo Ze)	B67 (Zhi Yin)	B1 (JingMing)
Shao Yang	SJ1 (Guan Chong)	Gb44 (ZuQiaoYin)	SI19 (Ting Gong)
Yang Ming	LI1 (Shang Yang)	St45 (Li Dui)	St8 (Too Wei)
Tai Yin	L11 (Shoo Shang)	Sp1 (Yin Bai)	Ren12 (Zhong Wan)
Jue Yin	Pc9 (Shoo Chong)	Liv1 (De Dun)	Ren23 (Yo Tang)
Shao Yin	H9 (Shoo Chong)	K1 (Yang Quan)	Ren23 (Lien Quan)

Diseases originating in the level or layer system are caused by invasion of “extreme pathogenic energies” (Evil Qi), i.e. those which are not specific for the particular season. These extreme Evil Qi do not invade the Regular Channels or Organs but affect the Collaterals causing thus the “strange diseases”. Except the clinical manifestations of affected Collaterals there are symptoms of Qi circulation disturbance in the affected layer.

Level	Symptoms of Levels
Tai Yang	the disease originates on the body surface: · pain syndromes are distinctly expressed; · due to reduced protection reserves, the organism is highly vulnerable to various diseases; · thinned skin and muscles of patient are notable in external examination
Shao Yang	Yang Qi circulation is disturbed which gives stagnation of pathogenic Qi: · muscles and joints are weakened and painful; · the patient is unable to assume a vertical position and run.
Yang Ming	Defensive Yang Qi is blocked and does not penetrate inside the body: · muscle weakness is increased, limbs become powerless; · there appear paralyses.
Tai Yin	Stomach Defensive Yang Qi may not penetrate deep and feed Zang Organs: · Qi and food transportation to the organs is disturbed; · symptoms of reduced energy are present, including violent diarrhea; · Zang Organs are blocked with symptoms such as abdominal distension and pains in the epigastrium region.
Jue Yin	Connection between the Yin channels is disturbed: · energy flood is reduced, stagnation exist, accompanied by symptoms such as general weakness, difficult labor and short breath in a rest position; · tendency to depression and mental diseases.
Shao Yin	Level does not close Yin inside: · Wei Qi is extremely deficient; · the patient permanently sighs and moans.

 

Affection of some level is usually accompanied by symptoms of Collaterals affection, including the Extra Channels. Thus the 3 Yin Channels affection is combined with Ren Mai; while Shao Yin affection is related with the entire Yin Wei Mai; Shao Yang and Yang Ming may combine with Dai Mai, while Tai Yang is related with Yang Jiao Mai, etc.

The aim of treatment of such syndromes is to restore the normal circulation of Defensive Energy (Wei Qi, or Yang Qi) both along the channels from “Roots” to “Knot” points, and between the layers. The affected channel must be “opened”, i.e. reinforced in case of Deficiency and sedated in case of Excess.

The Deficiency is caused by the lack of Defensive Energy (Wei Qi), therefore “Knot” and “Roots” points should be reinforced. When acupuncture is used, the needling should be shallow to prevent the penetration of Exogenous Factor into deeper parts of organism. Excess is caused by the Exogenous Factor which should be dispersed in the same points.