The purpose in understanding the 3 treasures(san bao) is to understand how to harmonise and unify or activate and cultivate all 3 treasures to gain superb health.
Jing is a refined essence (the character for jing means sperm/essence) it is the material(bodily-earthy) basis for all life. It influences our genetic constitution, vitality, power of presence-the power of our life and willpower, reproduction, growth and development, and longevity. It is the foundation for the production of Qi and aids in the production of marrow(mind too), There is Prenatal and Postnatal Jing.
Called essence, it is a mixture of sexual fluids(semen, menstrual fluid, vaginal excretions, saliva) sex hormones, hormones, adrenals,and biochemical fluids. Jing is found all over the body but accumulates in all the yin organs but most particularly the kidney organ where it is concentrated in the greatest amount
Jing means seed, and is basically referring to semen, it nourishes the entire body (it has to do with growth and development)with vitality, it is primarily used in Qigong: – by stabilizing and preventing its loss, the cultivator aims to convert Jing to Qi- to Shen, thereby allowing his eternal being(that which is immortal in him) to shine through with brilliance. This need not be a complicated process, in reading Ken Cohen’s book he advises that one should just concentrate on developing Shen, and all else falls into place, Rodger Jahnke seems to suggest the same thing “The most effective Qigong is actually focused primarily on the eternal self(Shen-my words)where our highest expression of perfect health already exists. The promise of Qigong is that if you focus on cultivating and expressing Shen Qi –revealing the latent presence of your spirit self-then health and productivity will arise spontaneously as side effects of your practice.”
– Jing most closely affects immunity, mental health ,vitality, Life power, personal power, and directly affects longevity particularly with regard to the postnatal qi form of jing.
Jing seems to be made up of a limited (unreplenishable) (However I have heard that there may be a way for advanced daoist adepts to affect the prenatal normally unreplenishable/uninfluenceable jing leading to the legendary Daoist immortals but few people accomplish this) quality which is inherited from your parents as genetic material and life vigor, and a replenishable component which is drawn from food and air to form normal Jing Qi.
Living a long and healthy life depends upon replenishing jing(tonic herbs), and accumulating /cultivating Jing(good diet, qigong , daoist yogic practices and preventing leakage of Jing)
Deterioration of jing can be accelerated by prolonged illness or overwork, injury, abuse, stress, exhaustion, excessive loss of semen(men) giving birth(women) and poor nutrition. Evidences of jing waning are thinning and graying hair, decreasing moisture throughout the body,drying out of the vagina, especially during sex. loss of sensory and mental acuity, and weakening of the bones, teeth, and connective tissue. The rate of deterioration can be slowed down by proper nutrition, adequate rest, balancing fun with work, qigong practices, techniques such as acupuncture, good dietary practices and herbal formulas for enhancing life force.
Jing correspondences: Jing corresponds to the body, Earth Qi, Yin energy, Lower dantien(earth elixir field), cultivated through good diet, exercise,Qigong, Dao Realm-Earth. – Cultivating Jing’s main intention is for healing the body/longevity.(and secondarily it supports all the other states of Qi and Shen)
Jing flow is actively reversed in order to promote longevity and mental health(it naturally flows down, but through meditative processes it is drawn up).
As an interesting side note Jing parallels the Ayurvedic concept of Ojas, it is identical in every respect to the Jing concept.
Qi is the vital energy or life force that flows throughout the body and through the Meridians, Yin -Yang organs, and it also has a relationship to moving blood.
Qi sources:breath, food and constitution(yuan qi)
Qi in the bodys functioning is like an electric current. Qi animates our being. Qigong practices assist qi circulation and flow, storage, and regeneration. Our qi circulation and flow is dependent on quantity and the quality of qi we received at birth from our ancestors, diet and nutrition, and overall lifestyle. Qigong Practices can transform qi into shen or jing and healing energy.
When the qi flow is disrupted, we accumulate the residue of incomplete vital process (toxins and blockages to the Qi/vitality). This is how many illnesses form. In the beginning of this disruption, there is stagnation. If the residue accumulates over time, they eventually manifest as disease.
All the forms of Qi ()are able to be replenished except the Yuan Qi(original Qi/prenatal Qi –gift from the universe/ancestors) Ken Cohen calls it Personal Original Qi
Our (hou tan qi-postnatal qi Qi can be augmented by cultivating the postnatal qi that comes from nutrition, TCM Herbal Tonics and breathwork(Breathing and Qigong) –Ken calls this Transpersonal Original Qi
We can learn to absorb this transpersonal original Qi, from the Heaven Qi and Earth Qi in Qigong practices, and through Meditation – Ken says that this transpersonal Qi is not part of our constitution it dissipates easily and thus requires dedication, persistence and consistent practice and sustained effort in order to sustain an abundance of it.
Qi corresponds to the heartmind,middle elixir field(middle dantien- roughly about the heart/thymus region) Qi is Zheng Qi, and it corresponds to the state of Harmony between Yin and yang(it is both), it is cultivated by Qigong, focused meditation,lifestyle focus should be upon calming emotions and having clear thought. Corresponds to the Human realm(dao realm)
As an interesting side note Qi corresponds to the Ayurvedic concept of Prana,
Shen can be roughly translated as spirit , and it is dependant on abundant Jing and Qi in order to develop and unfold and “bring forth the brilliance of the eternal self” it implies consciousness, mental health, vitality, and presence it is associated with luminosity .
Shen corresponds Spirit ,to the energy of heaven, and Yang energy, expansion, Heaven elixir(the Upper dan tien ) found around the 3rd eye to where the soft spot of the human head is (in children), it is cultivated through internal alchemy, and meditation, and spiritual practices. It corresponds to the Heaven Dao realm.
Shen can be reflected or seen in the brilliance or radiance of their presence, especially their eyes, Shen is also seen as disturbed in any serious mental illness,
Shen parallels the Ayurvedic concept of Tejas/Atman
I found the below text while researching Shen and liked it..
”Shen is not an automatic given to all who live and breathe like jing and qi are. It is achieved and augmented in the higher levels of meditation, taiji and qigong practice and through a lifestyle that is integral to these practices. Shen has to do with the hun, or Ethereal Soul. Shen is spirit and it is everywhere. It comes to us when we reach a higher level in our practices after much time and perseverance; it goes elsewhere when we neglect our practices, when we abuse ourselves, or live in an unvirtuous fashion. The shen is sparked and nurtured by music and dancing, participation in the arts and creative activities. The character for shen contains the idea of a bird. A bird is free to fly away. It is free to go when conditions aren’t favorable and may choose to remain when they are. We all have the capability through cultivation to have the kind of roost that the shen will be attracted to.
Healthy Shen depends on the strength of the Essence (stored in Kidneys) and Qi (produced by Spleen and Stomach). Thus, Shen is dependent on the Prenatal Jing and the Postnatal Jing. If Essence and Qi are healthy, the Shen will be nourished. As mentioned above, the Shen lives in the Blood Vessels, part of the Heart system in TCM. Blood is closely related to Qi in TCM, and is formed from the Postnatal Jing derived from food and fluids, hence Blood formation is simultaneous with that of the formation of Qi. “