Classical Korean Traditional Medicine worked by projecting the principles of the cosmos — yin-yang and the five phases — onto the human body. It is a coherent approach, and it left problems that would not resolve in the clinic. Sasang medicine attempted something different: analyse the human being first, then assign the organs accordingly. This article covers Sasang and the five phases, and one reassignment in particular.
On the status of what follows
The reassignment described here — spleen-stomach to fire, heart to earth — is best understood as an interpretive lens rather than a formal doctrine attributable to Lee Je-ma or to Dowon Kuon. As I explain below, Sasang practice in many places continues to follow the conventional five-phase assignments. What I am offering is a way of reading that makes a great deal of Sasang medicine legible, and I present it as that.
In Summary
- Classical KTM applied yin-yang and the five phases — a framework for understanding the external world — directly to the body, which left persistent clinical puzzles.
- Lee Je-ma reversed the direction: analyse the human being first, then assign the organs on that basis.
- Read through function rather than substance, the assignments shift: liver–wood, lung–metal, heart–earth, spleen–fire, kidney–water.
- Spleen-stomach as fire: the stomach dissolving food and generating energy works like a furnace. The source of caloric energy sits there.
- Heart as earth: the heart does not emit fire so much as coordinate and mediate the other four organs — the containing, balancing quality of earth.
- The reassignment clarifies the lung–liver and spleen–kidney antagonistic pairs, which is where its practical value lies.
- But conventional assignments persist in practice — the five transport points used in constitutional acupuncture follow classical five-phase reasoning.
- So this is a reading, not a replacement. Seen as fire rather than earth, much of Sasang medicine becomes legible.
- Sasang is not a master key. Some conditions need a human-centred lens; others need an environment-centred one.
The Problem Lee Je-ma Was Solving
Traditional KTM worked hard to project the principles of the universe and nature — yin-yang and the five phases — directly onto the human body.
But those principles are a way of understanding the external world. Applied straight to a person, they left puzzles that never quite resolved in clinical practice: patients who should have responded and did not, patterns the theory predicted that did not appear.
At this point the scholar-physician Lee Je-ma (1837–1900) attempted an innovative reversal of perspective. Rather than starting from the cosmos, start from the human being — analyse the person first, and assign the organs to the five phases according to what that analysis shows.
That reversal is the originality of Sasang medicine, and it is a considerable advance.
Substance Versus Function
The reassignment follows from a single move: read the organs by what they actually do in the body rather than by the form they were born with.
Assigned by function, the arrangement comes out as:
- Liver — wood (목 木): rising and dispersal of life
- Lung — metal (금 金): regulation of gathering and descent
- Heart — earth (토 土): governing and mediating the whole body
- Spleen — fire (화 火): energy production and caloric supply
- Kidney — water (수 水): storage and source of vitality
Compared with classical assignment — heart as fire, spleen as earth — this is a striking change. But consider the actual functions and there is a good deal to nod along with.
Two Kinds of Fire
The key to understanding the change is how one interprets the nature of fire.
The fire of life activity: ministerial fire in the spleen-stomach
Taking in food, dissolving it and producing energy — the stomach’s action works like an enormous furnace. The source of powerful energy, of calories, comes from the spleen-stomach. In terms of actual function, that is fire.
This is the reading behind what this site has said elsewhere about the heart receiving fire rather than producing it, and about stomach heat being the hottest region of the body.
The fire of life maintenance: sovereign fire in the heart
The heart is the symbol of life and maintains a beat that does not stop. But rather than emitting fire directly, it coordinates and mediates the other four organs and the whole body.
That is to say, it performs the function of earth — containing everything and holding the balance.
What the Reassignment Buys You
Through this rearrangement, the lung–liver and spleen–kidney antagonistic relationships become clearly legible. And with them come keys to constitutional diseases that previous frameworks could not resolve.
That is the practical payoff, and it is why the reading is worth holding even though it is not the only one available.
Why Conventional Assignments Persist
A student put a sharp question to me about this, and the answer belongs in the article.
The observation was that Sasang medicine appears in places to follow the conventional five-phase assignments rather than the reassigned ones — for instance in how constitutional identification points are chosen, where the five transport points (오수혈 五輸穴) are used according to classical five-phase reasoning.
That is correct. The conventional assignments are indeed followed in those contexts.
What I would say is this: looking at the symmetrical relationships between organs in Sasang, the spleen-stomach is matched as the pair to the kidney, which water symbolises — and on that basis one can regard the spleen-stomach as fire. And when you do, a great deal of Sasang medicine becomes much easier to understand.
Note the form of that claim. It is not the spleen is fire and the classical assignment is wrong. It is reading the spleen as fire makes the system legible. As the student rightly noted, the five phases were introduced as one way of explaining human physiology rather than as a mechanism physiology obeys — which is precisely why a constitutional medicine is entitled to shift the assignments where doing so explains more.
Is Sasang a Master Key?
Sasang medicine is a considerably advanced system that solved the problem of individual difference that earlier frameworks could not. Examining each patient’s innate vessel first has real affinity with what modern medicine pursues as personalised care.
But it does not follow that Sasang alone should resolve every illness in the world.
- Conditions needing a human-centred lens: chronic illness arising from constitutional imbalance, intractable disease
- Conditions needing an environment-centred lens: acute infectious disease, illness dominated by environmental factors
There are areas that are better treated by looking primarily at the external environment or at cosmological cycles rather than at the person. What we have gained is one more precise lens — and with it a broader, deeper view of how to heal a human being.
Summary
Lee Je-ma’s reversal — person first, cosmos second — is the substantive innovation. The reassignment of spleen to fire and heart to earth is the most visible consequence of it, and the most useful thing to know about it is that it is a lens rather than a correction.
Hold it that way and the antagonistic pairs come into focus. Hold it as doctrine and you will be puzzled by all the places where classical assignment still governs.
Related: What Makes a Heart Race: The Five Organs Behind the Symptom
