Chu Shong Tin could send younger, stronger people flying across a room while in a state of complete muscular relaxation. He wasn’t performing a trick. He wasn’t using leverage in any way a biomechanist could diagram on a whiteboard. He was doing something that most people would call impossible, and he could do it on demand, to anyone, at any time.
Chu Shong Tin was one of Ip Man’s oldest and most respected Wing Chun (詠春) students, and he had spent decades developing what he called “Nim Lik” (念力) - mind force. Power generated not by muscles but by focused mental intent, originating at the tailbone and projecting upward through the spine and out through the body.
One of his students, a doctor, arranged an MRI scan to see what was actually happening in his brain when he entered this state. When he switched it on, the machine readings went haywire - the changes were so dramatic the doctors told him to stop. The part of his brain that was lighting up was the cerebellum, the structure that mediates communication across the central nervous system. For decades neuroscience largely dismissed the cerebellum as a motor control centre and nothing more. Only in the last few years has the research caught up with what the masters always knew - a 2024 review1 finally consolidated the evidence that its role in social cognition and higher-order thinking had been systematically overlooked. The emerging view, building on Ito’s earlier work2, is that it encodes internal models not just of the body’s dynamics but of mental representations themselves. In other words, it may be the very substrate of embodied intuition.
Sigong Chu used to attend tea ceremonies with other top masters in Hong Kong - tai chi, baguazhang, and other internal styles - and they discovered that he was generating his force in a fundamentally different way. Where other styles channel power through the body in a wave-like motion, Chu’s force had no such pathway. He would expand the joints themselves, generating full power without any physical lead-up. No wind-up, no weight shift, no telegraphing. That is Nim Lik. I trained with him in Hong Kong and with his students for many years, and being on the receiving end of it is one of the strangest experiences of my life.
State, Not Shape
Even among the internal martial arts - styles that explicitly reject muscular force as the primary engine - there are degrees. Most still rely on structured body mechanics, wave-like transfers of momentum, rooted stances. What Chu was doing sat at an extreme that surprised even the other masters. The internal arts fascinate me because they demonstrate the existence of a force that can’t be generated by muscular exertion alone, and Nim Lik is the purest expression of that I’ve encountered.
The internal arts deal in “concepts” and “ideas” that can be applied in the body to transfer and deal with force. To learn these ideas, the student must feel them physically - not understand them intellectually, feel them - and train them to the point where the neural pathways are so well mapped out that they can be triggered by a single thought. The challenging thing for most people to reconcile is that these ideas don’t exist predominantly in the head. They’re directly related to a movement of energy through the body, and they can only be accessed through the body.
When talking with the masters you hear the same phrase over and over: “state, not shape.” If the underlying idea is working properly, the shape of the body or the technique being applied is irrelevant. The state of mind generates the force. Not the posture. Not the choreography. Not the hand position. The state.
This distinction - between state and shape - is possibly the most important idea I’ve ever encountered. And I didn’t encounter it in a classroom or a textbook. I encountered it through years of getting thrown around by old men who weighed half what I did.
The Body’s Hidden Network
So what is actually happening when a master generates force without muscular exertion? The answer has been inside us all along - literally woven through every layer of the body - but Western science has only recently begun to see it.
Fascia. The continuous web of connective tissue that wraps every muscle, bone, nerve, and organ in the body. For most of medical history it was treated as packing material - the stuff anatomists cut through to get to the important bits. That turned out to be one of the most significant oversights in the history of biology.
The fascial network contains approximately 250 million nerve endings.3 That makes it the richest sensory organ in the human body - not the skin, not the eyes, the fascia. And the type of nerve endings matters. The vast majority are interstitial receptors - type III and IV fibres - with up to seven times more interoceptors than proprioceptors.4 Proprioceptors tell the brain where the body is in space. Interoceptors tell the brain what state the body is in. The fascia isn’t primarily reporting position. It’s reporting condition.
These free nerve endings form a dense mesh woven directly into the fascial extracellular matrix, responding to stretch, shear loading, and mechanical pressure.5 They’re polymodal - each ending responds to multiple types of stimulation simultaneously. And they feed directly into the insular cortex, the brain’s centre for interoceptive awareness, emotional regulation, and self-recognition.4 When the masters say that an idea must be “felt in the body, not understood in the head,” they’re describing interoceptive processing through the fascial network. The felt sense is the fascia talking to the brain.
In 2021, researchers published evidence in Scientific Reports of a previously unknown neural network embedded within deep fasciae6 - a rhomboid lattice of nerve fibres running through the thoracolumbar fascia and deep connective tissues that nobody had mapped before. We didn’t know it was there. The masters had been using it for generations.
Now think about Nim Lik. Mind force that originates at the tailbone and projects upward through the spine. The thoracolumbar fascia is one of the most densely innervated fascial structures in the body - a multi-layered sheath that runs from the sacrum to the thorax, packed with mechanoreceptors, nociceptors, and the free nerve endings that connect directly to the central nervous system.7 It serves as a tensional force transmission system,8 distributing load from surrounding muscles across its layers independently of muscular contraction. The pathway Chu Shong Tin described - tailbone, spine, upward through the body - maps directly onto this fascial architecture. He wasn’t speaking in metaphor. He was describing the anatomy of a system that science hadn’t yet catalogued.
The cerebellum lighting up on the MRI makes more sense now too. It’s processing the largest sensory input in the body - a quarter of a billion nerve endings reporting the state of a continuous tensional network. Not motor control. Internal modelling. Exactly what the cerebellum was doing all along while neuroscience wasn’t paying attention. When Chu Shong Tin entered his condition, he wasn’t just relaxing his muscles. He was switching systems. Turning off the gross muscular apparatus and activating conscious control of a fascial-neural network that most people never learn to access because nobody told them it existed.
This is bidirectional. The mind controls the fascia, and the fascia controls the mind. Studies have shown that patients with chronic depression exhibit measurably higher fascial stiffness and reduced elasticity9 - the tissue literally tightens and loses its responsiveness. The inverse is what the internal arts train: deep relaxation increases fascial elasticity, which means a more responsive sensory network, which means clearer interoceptive signal, which means a more refined internal state. The practice isn’t stress relief. It’s tuning the instrument.
And the instrument runs deeper than biomechanics. Fascia plays a critical role in the regulation of neurotransmitters - serotonin, dopamine, GABA, acetylcholine - and is intimately connected with the autonomic nervous system.10 The “state” the masters access isn’t just a shift in force transmission. It’s a neurochemical event. A change in the operating condition of the entire organism, mediated by a tissue system that Western medicine spent centuries ignoring.
The masters discovered how to consciously operate a sensory-motor system that science didn’t even fully catalogue until 2021. They were decades ahead. And they didn’t need an MRI to know it was there. They found it the only way it can be found - by feeling it from the inside.
The question is what that feeling actually is.
Infusing the Spirit into the Spirit
Most people who practise Siu Nim Tao learn the movements. They stand, they move their arms through the positions, they build patience. What most of them never develop is the Nim Tao itself - the “small idea” that the form exists to cultivate. The form is the vehicle. The Nim Tao is what it’s building: an internal system that connects the spine, engages the cerebellum, and sets up the fascial-neural network as a living conduit. Without the Nim Tao, you’re just waving your arms around. With it, the body changes.
You can feel when it activates. The texture of the flesh transforms - it becomes jelly-like, simultaneously soft and alive, as if the muscular system has gone offline and something else has taken over. When Sigong Chu projected Nim Lik through this state, you could feel pulsations moving through his body. Not muscular contractions - there was no activation at all. Just waves of force moving through flesh that felt like it had no bones.
This is what Chu meant by “infusing the spirit into the spirit.” It’s not the mind directing the body. It’s consciousness intensifying itself until the body responds as a consequence. The Nim Tao establishes the conduit. The Nim Lik is what flows through it. And when someone is using Nim Lik properly, you cannot stop their movement. It doesn’t matter how much stronger you are, how well you’re braced, how ready you think you are. The movement is unstoppable because it isn’t being generated by anything you can oppose.
References
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Van Overwalle, F. (2024). Social and emotional learning in the cerebellum. Nature Reviews Neuroscience, 25, 776-791. ↩
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Ito, M. (2008). Control of mental activities by internal models in the cerebellum. Nature Reviews Neuroscience, 9, 304-313. ↩
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Fede, C. et al. (2022). Fascial Innervation: A Systematic Review of the Literature. International Journal of Molecular Sciences, 23(10), 5674. ↩
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Schleip, R. & Jager, H. (2012). Interoception: A new correlate for intricate connections between fascial receptors, emotion and self recognition. Complementary Medicine Research. ↩ ↩2
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Fede, C. et al. (2022). Innervation of human superficial fascia. Frontiers in Neuroanatomy, 16, 981426. ↩
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Fede, C. et al. (2021). Evidence of a new hidden neural network into deep fasciae. Scientific Reports, 11, 12623. ↩
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Mense, S. & Hoheisel, U. (2016). Evidence for the existence of nociceptors in rat thoracolumbar fascia. Journal of Bodywork and Movement Therapies, 20(3), 623-628. ↩
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Willard, F. et al. (2012). The thoracolumbar fascia: anatomy, function and clinical considerations. Journal of Anatomy, 221(6), 507-536. ↩
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Wilke, J. et al. (2021). Myofascial Tissue and Depression. Cognitive Therapy and Research, 46, 560-572. ↩
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Bordoni, B. et al. (2024). Fascia as a regulatory system in health and disease. Frontiers in Neurology, 15, 1458385. ↩