Until very recently in human history, most of the physical power we used in daily life came
from our own body.  Martial arts of this pre-industrial age, what we now call traditional martial
art, is at its most fundamental level the art of using the body’s physical forces:  how to
produce the various types of forces in the amount required, deliver them the most efficient
manner to an opponent’s body to cause him trouble, and prevent the opponent from doing
the same to us, etc.  

Today this large body of knowledge survives in traditional Chinese martial art.  Amongst
those styles, in terms of training and fighting with these forces, Taiji Quan offers the most
formally thought out, the most detailed, and the most clearly articulated set of principles and

Imposing in its breadth and depth, Taiji Quan today is never the less an art that is no longer
used for its original reason for existence.  For vast majority of the practitioners, the
emphasis of training has shifted from fighting to health.  However, if we totally ignore the
fighting aspects of the art, we risk not only losing that part of the knowledge, but
misunderstanding the very essence of Taiji Quan itself.  To do Taiji Quan means to practice
and understand it as what it is - a martial art.  Otherwise we are not really doing Taiji.  If we
are not really doing Taiji, then we will not even get the full health benefits of this training.  
For example, if we do not do any push hands, we will miss out on important lessons that
directly relates to how we should do the form.

To really master Taiji Quan, besides having the correct view of what Taiji Quan is, what the
end goal should be, and the training methodology for getting there, we need to have a
complete and accurate understanding of its principles and theories.  Here we will offer a
basic introduction on Taiji Quan theories on jin, one of the most important foundations for all
Taiji Quan skills.

1.  Li and jin

Martial art is like any other types of knowledge, it took a very long time to develop.  At first,
people had no principles or concepts, only hands-on experiences.  At some point those
experiences accumulated to a point where it was possible to summarize them as general
theories or principles.  People can then test out those ideas.  And if they turn out to be
correct, they could be used to improve the practice.  Better practice in turn leads to further
understanding of underlying principles, thus the cycle continues.

It is only natural that in the beginning, these concepts are undifferentiated, simple, and
coarse, and only became clearer and more refined gradually over time.  In terms of
understanding force, the first major distinction made in Chinese martial art is between that of
li and jin.  

In everyday usage, both of these words mean physical force, and can be used
interchangeably.  Very often, people use jin to denote a very large force.  In martial art,
these are technical terms with more precise definitions.  Li is simple muscular force, what we
call “untrained force”, “natural force”, or “instinct force”, because no prior training is
necessary before using it.  When we contract our muscles in a simple, natural manner,
doing things like bending the arm to bring a fork to the mouth, or extending the arm to push
a drawer shut, we are using li.  
Li is simple, its major attributes are quantitative: how big, and how fast.

If li is the raw, basic material, then jin is the sophisticated, finished product.  It is li transformed by practice,
something that produces the desired results with higher effectiveness and efficiency.  

Example: two identical twins, same size, same muscle composition – same level of li, one is a professional golfer,
the other never golfs.  Stepping onto the course for the first time, the untrained twin, lacking any knowledge of the
sport, can only use what he was born with - li.  If his first drive does not go as far as he hoped, his natural instant
will lead him to use more li – swing the club harder, with more speed.  His trained sibling uses something far more
powerful and sophisticated.  He has jin, and use it to great effect: he is able to drive the ball much further, place it
on the course with much greater accuracy, and often with much less effort.  

Jin is complex, its qualities are not just quantitative but qualitative.  

Li is a product of nature, jin a product of nurture.  Everyone is born with the ability to generate and use li, no one
has jin until they have gone through the necessary training.  As we have seen in the previous example, when we
start on an unfamiliar, new activity, simple muscular force is all we can use because we do not know anything
else.  This force tends to be highly clumsy, awkward, and inefficient.  For this reason in martial art we also call li
zhuo li – awkward, untrained force.  Zhuo also means muddy, the opposite of clearly distinguished, clean,
polished, and refined, characteristics we commonly associate with jin.  As we become trained, that li is gradually
transformed into jin, something much more effective and efficient.  For this reason jin is called “trained force”.

Transforming the primitive li into the sophisticated, refined jin is the one of the main objectives of any
sophisticated martial art practice.

In fact, we can judge the sophistication of a martial art style by its treatment of li and jin.  In less-developed styles,
the ideas about force tend to be very simple and coarse, with little or no distinctions made between li and jin.  
Since jin is more powerful than li, they may just consider jin to be a very large force developed from practice, and
that is the main reason why people think jin is better than li.  

When we try to do something and fail because we are met with resistance, our instinctive response is to try again
with greater force.  This is our human nature.  Martial arts of this level follow that nature, not only in force training
but in its general strategy and tactics.  This makes them very easy to understand and appreciate.  Here they
believe the path to invincibility is simple, through maximizing power and speed.  As a result in fighting, they can
only practice and use jin only in very simple ways.

But as a style matures, the distinction between li and jin becomes clearer and more refined.  People start to have
a fuller appreciation of what can be accomplished with jin.  It is also noticed that even though muscle actions are
involved in both, li and jin work in very different ways, and therefore different training methods are required.  So
the emphasis of force training changes, it becomes far more complex.  Now the goal is nothing less than the
complete development of jin in all its quantitative and qualitative aspects.  

The qualitative aspects of jin can be very subtle and difficult to observe from the outside.  When combined with
high-level principles, we can use jin to do things such as using a small force to defeat a very large one.  Today
these types of things seem incredible to us because most of us in our modern sedentary lives are only familiar
with li, and know very little about jin.  Today high-level martial art is like great works of modern art, to the untrained
eye, it may seem strange, unnatural, counter-intuitive, or even fake.  

2.  Wai Jin and Nei Jin

 In the past 400 years we saw the rise of a new class of martial art.  More effective than ever, their real
significance is that they represent a giant step forward in efficiency. This was made possible by the second major
development in the theory of force in martial art.  By this point people had enough knowledge about jin to make
further distinctions between two main types of jin:  wai jin - external jin, and nei jin – internal jin.  New knowledge
gained from the research into internal jin gave birth to internal martial art.  Its members are Xingyi Quan, Taiji
Quan, and Bagua Zhang.

To be called an internal martial art does not mean it uses only nei jin.  No martial art can be complete without the
use of wai jin.  So internal martial art just means the emphasis during training and fighting is on nei jin, with wai jin
playing the supporting role. Conversely, to be called external martial art means it uses mostly wai jin and very little
nei jin.  

So what exactly are wai jin and nei jin, and why does internal martial art favors the use of nei jin?  To answer that,
we will first take a look at what they are, and then how they are tied to the central philosophy of internal martial
art.  As Taiji Quan is the most systematic and detailed in making these distinctions, we will use it to illustrate these

2.1 Definition

Wai means outside or external.  To be outside is to be visible.  So wai jin means the type of jin where, when used,
an observer can, just by seeing it, understand every aspect of that force:  how that force is stored and released,
its speed, angle, direction, etc.  We are using wai jin for example when we do a quick and hard punch.

By definition wai jin is yang.  Yang in Taiji is not the pure yang, it has a little bit of yin in it.  This is called gang
zhong rou – hard containing the soft.  The advantages of wai jin are that it is quick, hard, sudden, and powerful.  
When released, the feeling is like that of an explosion or eruption, unstoppable, capable of destroying everything
in its path.  It can be used to seriously injure or kill the opponent.

The disadvantages of wai jin are: generally the movements are large, and given its external nature, making it
relatively easy to detect and defend against.  The duration of its power tends to be short. And once released, you
cannot easily change its trajectory or any other attributes of that force easily.  Finally, the storage and release of
power here are completely separate processes.

The key points of using wai jin are speed, power, and accuracy.  Practicing wai jin is about fulfilling our potential.
Some internal martial arts masters can release incredible power.  It is about absolute quantity; we want to build up
as much of it as possible during practice.

Common types of wai jin used in Taiji Quan are:  duan jin – breaking force, chuang jin –ramming force, cun jin –
one inch force, leng jin – cold force, dou jin – shaking force, and chong jin – charging force, etc.

Nei means inside or internal.  To be inside means it is something that cannot be seen, only felt.  An example of nei
jin is nian jin in Taiji Quan.  When we can stick to our opponent perfectly without either struggling against or lose
connection with him, there is almost no physical movement at the contact point between two of us, yet inside our
force is having its effect.  The external movement is so minimal and subtle that it escapes the eye.

By definition nei jin is yin.  Yin in Taiji is not the pure yin, it has a little bit of yang in it.  This is called rou zhong
gang – soft containing hard.  The advantages of nei jin are that it is small, long, changeable, and combines the
storage and release process.  Small means the movements required are in general very small, sometimes not
even visible externally.  Long means when the force is released, the effect can continue on for a relatively long
time.  Changeable means its quantity and direction can be altered during its release.  The processes for storing
and releasing are one, with no clear separations and breaking points in between.  The combination of all these
attributes makes it easy for us to conceal our true intentions. With nei jin, making accurate determinations about
its amount, direction, angle, direction, etc, are very difficult, making it much harder to defend against.  

The main disadvantage of nei jin is that, although you can use it to move people easily, it is not powerful enough
in itself to be truly destructive.  

The key points of using nei jin use are changeability, subtlety, and concealment.  Practicing nei jin is about
developing more subtle and refined skills.  Nei jin is more about the relative than the absolute.  It is qualitative in
that it is more about how to control and use our force.  Most high-level skills in Taiji Quan come from this type of

Common types of nei jin used in Taiji Quan are:  chang jin – long force, chen jin – sinking force, zhan jin –
adhering up force, nian jin – sticking to force, lian jin – linking force, and sui jin – following force, etc.
2.2 Taiji Quan’s approach to fighting with nei jin and wai jin

As we can see, the characteristics of nei jin and wai jin complement each other in fighting, so
it is wrong to ignore either one in our training.  As each type of jin has its own unique set of
features, advantages, and disadvantages, during training we must strive to understand all of
them in detail, so that when fighting we can use each when appropriate, as dictated by the
principles of Taiji Quan.  

So what is the principle of Taiji Quan, and how is it different from external martial art?  

How we fight – tactics, is always constrained by what we have available for fighting –
weapons.  Before internal martial art, before we knew a lot about nei jin, our main weapon
was wai jin.  As we have discussed above, wai jin’s main attributes tend to be quantitative,
and that had an effect on how people fought.

The other major factors that influenced tactics are human nature and level of
understanding.  Skills in martial art, whether for attack or defense, are always designed with
the opponent’s possible response in mind.  What do we do instinctively when a force comes
- fight or flight.  In the former scenario, we basically try to prevent the force from landing on
our body by resisting it directly with an equal or greater force.  
Taken these things together, one arrives at the logic conclusion that, if I just make myself stronger, then people
will have a harder time to defend my attacks directly.  This line of thinking follows our natural instincts.  It is what
drove the development of wai jin, pushing it to a very high level.  But fighting this way, the bigger and stronger
person tends to win rather easily. Although the skills can make some differences, all skills base on this principle.   

By the late Ming Dynasty and early Qing Dynasty, people started to get away from this purely quantitative
approach.  People started to investigate the other characteristics of force, things like timing, angle, and direction.  
This is a more sophisticated, more comprehensive approach that also takes into account all the qualitative
aspects of force.  People still cared about winning, but the emphasis of research has shifted from effectiveness to
efficiency.  How can we win with less effort?

Traditional Taoist philosophy says the soft can overcomes the hard.  Applied to martial art, it means we do not try
to resist directly against an incoming force with an equal or greater force, and instead of having all the force come
from us, we try to borrow our opponent’s force to use it against him, etc.

In Taiji Quan we always want to achieve maximum results with minimum effort.  Translated into tactics, that means
we do not just use wai jin to attack the opponent directly.  We only do that after we have destroyed his balance
and have him under our control.  This is a highly complex process involving a lot of changes.  For this stage of
fighting, nei jin is the best choice.  Once we gained control, we need a finishing strike.  For that wai jin is the best

2.3 Popular Misconceptions

Li is external force, jin is internal force:  

Many people confuse li with wai jin.  The implication being external martial art people do not practice jin, they only
use li.  This is simply not true.  All martial art are based on use of jin.  External martial art people uses mostly wai
jin.  Some people think jin is an unique feature of internal martial art.  Internal martial art people use the term jin
more because they research and make distinction between the various types of jin in far greater detail.  If we do
not make this type of distinctions, then we do not even have to use that term – it is all just force to us.

Confusing wai jin for nei jin – be careful when other groups talk about nei jin:  

Judging by our long history, internal martial art is a fairly recent phenomenon.  This distinctions between wai jin at
nei jin is only made clear in a few styles.  So in most groups, when people mention jin or nei jin, usually they really
mean wai jin.  For people in those groups, this is not a big deal: if they do not make clear distinctions, than most
likely nei jin does not play a big part in making their skills work.  However, if we confuse the two in our Taiji Quan
practice, we may never get real Taiji Quan skill.  We maybe able to fight, but we will be using mostly wai jin and
using principles associated with wai jin.   We maybe able to win, but we are not using the highly efficient skills of
Taiji Quan.

So be careful, practicing internal martial art means the primary focus of your training is on learning how to use the
various types of nei jin.  

Nei jin’s are much more complex and difficult to understand and practice than wai jin.  To relax and follow when
confronted by a large force is not something that comes naturally to us.  But this how Taiji Quan fighting should
be, this is one of the central ideas.  Unless we can do this, we are not using real Taiji Quan skill.  This is the most
import thing, and it must be learned first.  

The other reason for learning nei jin fist is that it is higher level than wai jin.  The idea is, if we can master nei jin,
then we can master wai jin rather easily.  But if we devote most of our time to wai jin and ignore nei jin, we will
never understand nei jin and therefore internal martial art skills.

Wai jin’s by comparison are fairly easy to understand and practice because they are closer to our natural ability.  
Most people can understand them very quickly.  The difference in skill level amongst people comes down to how
well they can execute them - how much force can they produce, and how quickly can they release it.  

Confusing wai jin for nei jin – be careful when Taiji people talk about nei jin:  

Since Taiji Quan is an internal martial art, when people talk about jin in Taiji Quan practice, they are usually
referring to nei jin.  This can cause a lot of confusion, leading people to believe they are practicing/using nei jin
when in fact they are doing wai jin.  Remember not every jin used in internal martial art is nei jin.

In the early records of Taiji Quan principle, somewhere people even used li instead of jin. It is because the terms
are not normalized at that time. So even today, some people still talk in this way in their oral teaching. Actually it
really makes a lot confusing.
Yin Cheng Gong Fa Association North American Headquarters
Copyright © 2000 YCGF_NAH. All rights reserved.
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Zhang Yun (left) pushes hands
with Strider Clark
Great Master Wang Peisheng
(center) pushes hands with
Master Luo Shuhuan. Zhang
Yun stands behind.

Wai Jin
Nei Jin
Great Master Wang Peisheng
pushes hands with Zhang Yun