After reading our previous article on the Yi Jin Jing/Xi Sui Jing, in which I used analogies from bow making and swordsmithing to explain some of the possible mechanisms of Yi Jin Jing practice, my friend Peter wrote me mentioning that in relation to Yi Jin Jing/Xi Sui Jing I might want to look into the “planishing” process which both smooths out and hardens steel plate armour.
Planishing is a process in which metal plate armour is lightly tapped with a metal hammer or a mallet made of rawhide, usually against a firm surface such as an anvil, to smooth out small dents and declivities that occurred during the shaping process. This removes depressions in the smooth surface of the armour that are potential week points, while also rounding the armor so that the force of blow goes into the steel rather than the wearer. At the same time thousands of relatively light taps with the hammer alters the crystalline structure of the steel by stretching and then breaking the bonds between atoms and rearranging them. This reduces the ability of crystals to move within the metal structure and the metal becomes more resistant to further deformation.
Planishing is sometimes referred to as stress-hardening or work-hardening. To a degree the more you compress and work-harden metal, the harder and stronger it gets. There is a limit, which is different with different metals, at which the metal becomes too hard and therefore brittle.Nearly all steels can be work-hardened to a small degree. Jewelers lightly tap wire jewelry with nylon or rawhide hammers to strengthen the wire so that it retains its shape with repeated handling.
Numerous studies have been conducted on how bone becomes stronger when subjected to stress. Gravitational stress is one important element in building healthy strong bones. Another type of stress that strengthens bone is the kind of impacts that are part-and-parcel of martial arts training. Bone hardening from repeated impacts with another practitioner’s arms in Seven Star Arm Banging drills or hitting wooden posts have been shown to compress the bone, creating tiny micro-stresses that lead to thicker bone and increased bone mineral density. In one study on adolescents, those engaged in high-impact sports were shown to have a significantly higher total bone mineral density (BMD) and appendicular muscle mass (AMM) than the controls. Adolescents who participated in combat martial arts (like Judo and Karate) had significantly higher bone material density in their hands, arms, and legs than comparable adolescents who did not. Since the development of bone mass and structure is most significant during adolescence, the potential to increase the bone mineral density is greatest during this time. However, bone mass and bone structure can also be increased or modified through specific training performed after adolescence.
In Yi Jin Jing An-Mo/Pai Da (Pressing Rubbing/Patting Striking) practices, one rubs and lightly strikes different sections of the torso, and later the arms and legs, in order to “fill-in” declivities and thicken and strengthen the tissues. This practice takes place over a year or more with thousands of light, penetrating strokes, pats and strikes. An-Mo/Pai Da is said to develop and strengthen the Wei Qi (Defensive Qi) so that it becomes more resilient and adaptive with an expanding, outward-pushing force. The image of planishing can be very useful here. The light taps of the hammer in planishing that change the crystalline structure of the metal making it stronger and denser are akin to the loose-fisted rebounding strokes used in Yi Jin Jing An-Mo/Pai Da.
In effect, the body’s “armour” is the Wei Qi and its intimate connection with the fascia. Wei Qi has its roots in the deepest layers of the body, but it flows outward to the exterior of the body to warm the skin and protect us from both physical trauma and to prevent the penetration of pathogens into the body. Wei Qi helps us to adapt to external forces acting on the body. The strength and adaptability of the Wei Qi directly flows from three components: the physical structure of the body (physical form), the body’s internal energy (Qi), and a penetrating and lively spirit (Shen). By practicing An-Mo/Pai Da we in effect stress-harden the tissues of the body.
Modern science has found that connective tissue and cells have a quasi-crystalline structure and to some degree, behave like crystals. These crystals are piezoelectric – they generate electric fields or electric pulsations when deformed through compression, shear, or stretching. These electrical fields are thought to have a strong proliferative impact on the tissues in the area being stretched, compressed or sheared.
Subtleties of Forging the Body
In sections of the “original text” on Yi Jin Jing and Xi Sui Jing one can glean practical advice on the importance of the correct approach to training. These classical texts have been reproduced in various contexts and with different translations by different authors. I found the following quote, which first appeared in The Beverages of Chinese Kung Fu, a primary source edition from classical Chinese texts translated into English in the late 19th century by Dr. John Dudgeon. Dudgeon was at that time professor of Western Anatomy and Physiology at the Imperial College in Beijing who had a deep interest in Chinese culture. There is an extensive section on Yi Jin Jing in his book. Although Dudgeon’s English translation is a bit quaint, its very quaintness gives the translation a unique power, hence I find his translation both useful and illuminating. I have added the bracketed words to the text below.
The animal vigor [Qi] and spirit [Shen] are immaterial but the sinews, bones and muscles are material. The method is to discipline the material as the assistants of the immaterial and cultivate the immaterial to aid the material. These two are intimately related. If it is desired to discipline the sinews, the animal vigor comes first in order, then the membranes [fascia] and last of all the sinews, which is then easy. To discipline the membranes is difficult, but to discipline the animal vigor is the most difficult of all. The true plan is to lay the foundation in the difficult.
If the sinews are disciplined and not the membranes, there is nothing for the membranes to govern and vice versa; if the two are disciplined and not the air [respiration and Qi], the two do not increase in strength; and if vice versa, the air remains weak and fails to flow to the blood vessels. But reciprocally if the sinews are strong, but not strengthened by the air and membranes, it is like planting herbs without earth.
Pan-la-mi says that disciplining the membranes comes first, but in order to accomplish this the discipline of the air [Qi] is the lord or root of the matter. Most people do not understand the membranes. These are not the fatty membranes, but rather the membranes of the tendons; the former are in the middle of the breast, the latter are outside the bones. The membranes are the things that connect the vessels, arms and body; they protect and are in contact with the bones and sinews of the body. Comparing the sinews and the membranes, the latter are the softer, they are harder than flesh and are inside the flesh and outside the bones; they are the substances that embrace the bone and support the flesh. In Kung-fu, the air must traverse to the middle of the membranes, protect the bones and strengthen and support the sinews, which together form one body. This is the whole of Kung Fu.
More on How Muscle-Tendon Change & Marrow Washing Mechanisms
In Yi Jin Jin exercises you develop the Qi inside the limbs to strengthen the physical body (skin, muscles, sinews, fascia and bones), filling these structures with Qi. This in turn frees obstructions and blockages in these structures and in the meridians, feeding Qi back to nourish the internal organs. Some of the exercises also increase circulation around and inside the organs and enhancing their intrinsic movement and functioning.
The Mind-Intention plays a very important role in correctly conducting Qi to the tissue and through the meridians so that Qi concentrates and increases without dispersing. There can be no excess external muscular tension, otherwise the elastic qualities of the tissues will not be improved and the sinew and fascia will not be properly nourished and developed. Qi must go out to the limbs and the external structures and then flow back to the Dan Tian, the internal organs, spinal cord and brain.
While the Muscle Tendon Change focuses on Qi, Marrow Washing focuses on Jing and blood (Xue). The Muscle Tendon Change focuses on the membranes and spaces with the fascia, and Marrow Washing focuses on the on the marrow inside the bones. Creating a reservoir of Qi in the various layers of the fascia, and particularly in the layer between the bones and the sinews/muscles, helps to lead breath and Qi to enter the bones and stimulate the production of blood and marrow. In Marrow Washing Nei Gong, Qi and breath are guided into the bones longitudinally through the joints, and into the bones via the small channels (“network vessels”) that wrap the bone. This combination strengthens the bones and stimulates the bone marrow, thereby increasing the production of Jing and blood, while nourishing the tissues and improving circulation to every part of the body.
The “marrow” in Chinese medicine is considered to be a product of Kidney Jing (Essence). The concept Marrow in Chinese Medicine includes the bone marrow, but also fills the brain and the spinal cord. In self-cultivation practices like the Muscle Tendon Change and Marrow Washing Nei Gong, Qi and Jing are lifted upward along the Du Channel inside the spine, to be transformed into a substrate that nourishes the brain and the nervous system. Ancient Chinese medical texts, like the Ling Shu (Spiritual Pivot), tell us that when Sea of Marrow (the brain) is full and sufficient, it results in facile strength, and much power; the self exceeds its limits. When the Sea of Marrow is insufficient, it results in revolving of the brain, noises in the ear, weakness of the legs, dizziness with spots [in front of the eyes], and the eyes without vision. There is a languid idleness with desire to lie down calmly.
In addition to guiding Qi and breath into the bones to stimulate the bone marrow, Marrow Washing Nei Gong also uses the body fluids to augment and replenish Jing. In Chinese medicine, Jing refers specifically to Kidney Essence, the root of the body’s energy and the physical substrate, the root, underlying Qi and Shen. Strong Jing promotes strong Qi and Spirit. In Daoist practices replenishing Jing is often precursor to spiritual transcendence. In shamanic practices and in Qi Gong traditions, Jing also refers to the fluids of the body. We are mostly composed of water and as some Daoist practitioners point out, the body is a container for water. Therefore, refining water (fluids) is a method refining Jing.
In Marrow Washing Nei Gong one swallows saliva, guiding it down to Dan Tian, where it is transformed into a “mist” that is used to nourish Jing, the internal organs, limbs, spinal cord and Brain (the “Sea of Marrow”). The saliva contains a sweet liquid known as Jade Fluid (Yu Ye), which was created by Jing processed in the marrow of the brain. Swallowing this liquid and guiding it to Dan Tian replenishes Kidney Jing and blood, which when guided into the bones and spine creates more efficient production of marrow and blood. Swallowing saliva and moving it throughout the body also replenishes, refines, and adjusts the body’s fluids (another aspect of Jing). The body fluids in turn nourish the organs and the fascia.
In the Marrow Washing closing method, one gently massages body, infusing the head, torso and limbs with Jing and Qi, and sensing that even the lightest strokes penetrate into the bones and sinews to guide fluids, blood and Qi into the small spaces in and around the tissues.
Benefits of Marrow Washing
Marrow Washing is to strengthen and clean four aspects of the marrow:
- Bone Marrow
- Spinal Cord Marrow
- Kidney Tissue
The Benefits Ascribed to Marrow Washing are:
- Strengthens Immune System
- Augments Qi
- Improves Circulation
- Strengthens the Kidneys
- Replenishes Jing
- Purifies the Marrow & Produces Good Quality blood
- Improves Cerebral Function
- Produces a Clear and Penetrating Spirit
Reducing Fat & Turbidity
Together Yi Jing Jing and Xi Sui Jing are said to reduce the four body fats. “Fats” in this context includes turbidity that collects in areas of the body and blocks normal circulation. The Yi Jing Jing and Xi Sui Jing “melt” and transform turbidity so that clear Qi can circulate without obstruction.
- Meat Fat: fat stored in the muscle bands
- Visceral Fat: stored in the organs
- Blood Fat: blood viscosity
- Marrow Fat: in the bones – which blocks bone marrow regeneration and blood cell production and weakens the bones.
In traditional Chinese medicine the essence of turbidity can be understood in terms of abnormal functioning of zang-fu organs, due to the impact of heavenly, earthly and human processes. The turbidity of the heaven includes not only the traditional six evils – cold, hot, damp, summer heat, heat, and dryness, but can also include air pollutants and a large number of pathogenic microorganisms, noise, electromagnetic radiation, etc. The turbidity of earth refers mainly to contaminated water and food, while the turbidity of human processes refers to unclean or improper diet, disease processes, poor living standards, stress and negative emotions and thoughts, and habits like excessive drinking or smoking.
Turbidity can be understood as a greasy, dirty, phlegm-like substance that becomes stuck in the specific layers of the body – blood vessels, channels and collaterals, in and in between tissue and membrane layers, in the organs (for example gooey stuck phlegm in the lungs) and even in the head and brain. Turbidity is often described as phlegm – phlegm that is substantial, that we can see (like coughing up phlegm), and phlegm that is liss obviously substantial, that can be trapped within the network vessels or cloud the head and interfere with mental processes. A number of my colleagues in traditional Chinese medicine have observed that the “brain fog” associated with long COVID seems, from a Chinese medicine perspective to be tied to a form of endogenous turbidity, and herbs that transform and disperse turbidity, phlegm and blood stasis have been clinically effective in treating this condition.
Turbidity includes the concept of substances that cannot be properly decomposed – these could be nutrient substances, and toxins created endogenously, or from the outside that the body that cannot be broken down for one reason or another. These substances are inactive and cannot participate in normal material syntheses and decomposition. If these inactive substances they cannot be degraded, dispelled, or transformed, they will accumulate inside the human body and become a type of endogenous turbidity. Turbid “toxins” can result in pathological changes in the cells, tissues and organs that lead to dysfunctional processes such as inflammation, hypertrophy, hyperplasia, atrophy, and even lead to functional failure.
How do Yi Jin Jing and Xi Sui Jin dispel and transform turbidity (the Four “Fats”). I don’t have a good answer for this yet – again this is something that requires more research. However I suspect that engaging the Mind Intention and the breath to move and open the joints and gently stretch and re-orient the fascia, combined with stroking and patting the body over a long period of time, is a means of breaking up turbid fat deposits so that they can be transformed and dispelled. This process is likely greatly aided by “washing” the marrow and the membranes.
Yin & Yang in Muscle-Tendon Change and Marrow Washing
The Muscle-Tendon Change and Marrow Washing have both Yin and Yang aspects and we can say that they also act together in a global Yin-Yang relationship.
Yin Aspect: Gathering and storing Qi
Yang Aspect: Releasing Qi in the tissues as they stretch and move
Yin Aspect: Cultivation and production of blood, Jing and fluids
Yang Aspect: Promotes movement of blood, Jing and fluids through tissues and membrane spaces
Global Relationship of Muscle-Tendon Change and Marrow Washing
- More Yang
- Focuses more on the Qi
- Guides Qi to the more external parts of the body – fascia, sinews and membranes
- More Yin
- Focuses more on Jing, marrow, blood, and fluids
- Guides Qi and fluids (Jing, blood, etc) to the inside of the bones, the internal organs spinal cord, and brain.
 Andreoli, Angela; Monteleone , Maurizio, Van Loan, Marta ;Promenzio Luigi,; Tarantino, Umberto, De Lorenzo, Antonio;. Effects of different sports on bone density and muscle mass in. highly trained athletes. Medicine and Science in Sports and Exercise 33(4):p 507-511, April 2001
 “Fascial plasticity – a new neurobiological explanation: Part 1” Robert Shleip (Journal of Bodywork and Movement Therapy January 2003).
 The Beverages of Chinese Kung Fu: or Tauist medical gymnastics: the population of China: a modern Chinese anatomist; and a chapter in Chinese surgery – Primary Source Edition. John Dudgeon (Tietsin: the Tietsin Press 1985). The text of this book has largely been reprinted as Chinese Healing Arts by William R. Berk (Unique Publications 1986).
 Ling Shu or the Spiritual Pivot, Wu Jing Nuan , trans. (Washington DC: The Taoist Center, 1993) p. 133.
 Vital Breath of the Tao: Chinese Shamanic Tiger Qi Gong – Laohu Gong. Zhongxian Wu (London: Singing Dragon, 2008).
 Qi Gong Vol. 2 Yi Jin Jing Classic of the change of Muscles and Tendons. Constatin Boboc and Bernd Höhle (Martial Arts Association – International: 2021) p. 23,
 Fan XR, Tang N, Ji YX, Zhang YZ, Jiang L, Huang GH, Xie S, Li LM, Song CH, Ling JH. [Exploration of the Essence of “Endogenous Turbidity” in Chinese Medicine]. Zhongguo Zhong Xi Yi Jie He Za Zhi. 2015 Aug;35(8):1011-4. Chinese. PMID: 26485920.