Applied systems

Constitutional medicine

Between the Supreme Polarity and the eight trigrams sit the four images. A Korean physician took those four as a typology of human beings, gave each its own physiology, temperament and pharmacy, and produced a system still taught in Korean medical schools and practised in clinics today.

4
constitutional types
1894
year of publication
8
Korean medical colleges teaching it

The types and their machinery

Four types, each defined by a pair of strong and weak organ systems, with a characteristic temperament, physique, disease tendency and treatment set.

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The four images

China and Korea from the Great Treatise

Greater yang, lesser yang, greater yin and lesser yin, the stage between the two modes and the eight trigrams. In the classic they are a cosmological step; Lee Je-ma read them as a classification of people.

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Taeyang, greater yang

Korea 1894

Strong lungs, weak liver. Described as decisive, socially assertive and prone to overreach, with a developed upper body. The rarest type by a wide margin, which limits clinical experience of it.

☀️

Soyang, lesser yang

Korea 1894

Strong spleen, weak kidneys. Quick, outgoing and impatient, with a fuller chest than lower body. Digestive heat and urinary complaints are the characteristic vulnerabilities.

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Taeeum, greater yin

Korea 1894

Strong liver, weak lungs. Steady, patient and inclined to accumulate, often heavier in build. Respiratory and metabolic problems are the pattern to watch, and this is the commonest type in Korean populations.

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Soeum, lesser yin

Korea 1894

Strong kidneys, weak spleen. Careful, inward and easily chilled, usually slighter in frame. Digestive weakness and cold patterns are the recurring difficulty.

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Strong and weak organ pairs

Korea 1894

Each type is defined by one over-strong and one under-strong organ system. Health is the management of that imbalance rather than its correction, since the pairing is considered constitutional and lifelong.

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Temperament as diagnosis

Korea 1894

Lee Je-ma treated emotional disposition as physiologically causal, not merely correlated. Sorrow, anger, joy and calm are each tied to a type, and their excess is a mechanism of disease.

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Determining the type

Korea 1894 onward

By build, facial structure, voice, temperament, digestion, sleep, sweat and response to particular foods and herbs. It is the central clinical act, and the hardest part of the system to do reliably.

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Type-specific pharmacy

Korea 1894 onward

Each type has its own materia medica, and the same herb may help one type and harm another. This is the system's sharpest departure from standard East Asian medicine, where formulas follow the pattern rather than the person.

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Type-specific diet

Korea 20th century onward

Food lists by constitution are the most popular application, widely circulated in Korean health publishing. Also the part with the loosest connection to the original text.

↔️

Against pattern diagnosis

Korea and China 1894 onward

Standard Chinese medicine treats the presenting pattern, which can change from visit to visit. Sasang treats the constitution, held to be fixed for life. The two produce different prescriptions for identical symptoms.

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The research programme

Korea 1990s onward

Korean groups have looked for genetic, metabolic and anthropometric correlates of the four types, and produced standardised typing questionnaires. Results are mixed and the search continues.

Origins, texts and standing

Where the system came from, how it is used now, and what the evidence does and does not support.

Lee Je-ma

1837–1900 Hamgyong province

Physician, soldier and official who published the system in 1894 after decades of practice. He is said to have been driven partly by his own poor health, and he revised the work until his death.

Dongui Susese Bowon

1894 Korea

The founding text, whose title is usually rendered as Longevity and Life Preservation in Eastern Medicine. It sets out the four types, their physiology, their temperaments and their treatments.

The four images in the classic

c. 3rd century BCE China

The Great Treatise says the Supreme Polarity generates the two modes, which generate the four images, which generate the eight trigrams. Lee Je-ma took the intermediate step and made it a human typology.

The Confucian psychology

Joseon Korea

His account of sorrow, anger, joy and calm sits inside the Joseon debate about the four beginnings and seven emotions. Sasang is as much a product of Korean philosophy as of medicine.

The Korean medical tradition

1613 Korea

Heo Jun's Dongui Bogam had already established a distinctively Korean medical literature. Lee Je-ma was working within a mature national tradition rather than importing one.

In Korean medical education

contemporary South Korea

Sasang is a required subject in Korean medicine degrees and a recognised clinical specialty, with its own academic society and journals. This is not a fringe practice in its home country.

Eight-constitution medicine

1965 onward Korea

Kwon Do-won's extension splitting each of the four into two, with its own diagnostic pulse method. A separate school, sometimes confused with Sasang proper.

Standardised typing instruments

2000s Korea

Validated questionnaires such as the QSCC series were developed to make typing reproducible between practitioners, which had been the system's most obvious methodological weakness.

Genetic and metabolic studies

2000s onward Korea

Association studies have reported correlations between constitutional type and certain markers. Findings are inconsistent and sample sizes often small; nothing is established.

The Korean intellectual context

Joseon Korea

Sasang belongs to a wider tradition in which the Changes supplied the working vocabulary of Korean philosophy. The Juyeok school page covers that background.

Popular constitutional diets

late 20th century onward Korea

Type-based food advice is widely published and consumed in Korea, well beyond clinical settings, and is where most Koreans encounter the system.

The clinical caution

contemporary everywhere

Because the system holds that a remedy correct for one type can harm another, self-typing from a questionnaire and self-prescribing herbs is exactly the use its own logic warns against.

From cosmology to bodies

The Great Treatise describes a sequence: the Supreme Polarity generates the two modes, the two modes generate the four images, and the four images generate the eight trigrams. The four images, greater and lesser yang and greater and lesser yin, are usually passed over as a step on the way to the trigrams.

In 1894 a Korean physician named Lee Je-ma stopped at that step and asked what would follow if the four images described kinds of people. His answer was Sasang medicine, and it is the most fully worked-out clinical application the Book of Changes has produced anywhere.

The four types

Each type is defined by a pair of organ systems, one constitutionally over-strong and one under-strong. That imbalance determines physique, temperament, disease tendency and what will treat the person safely.

Taeyang, greater yang, has strong lungs and a weak liver: assertive, decisive, developed in the upper body, prone to overreach. It is much the rarest type, which means clinical experience of it is thin.

Soyang, lesser yang, has a strong spleen and weak kidneys: quick, sociable, impatient, fuller above than below, with digestive heat and urinary vulnerabilities.

Taeeum, greater yin, has a strong liver and weak lungs: patient, steady, accumulating, often heavier in build, watching for respiratory and metabolic trouble. It is the commonest type in Korean populations.

Soeum, lesser yin, has strong kidneys and a weak spleen: careful, inward, easily chilled, generally slighter, with digestive weakness the recurring problem.

Why it is not ordinary Chinese medicine

The difference is fundamental rather than one of emphasis. Standard East Asian medicine diagnoses a pattern, a configuration of signs that a patient presents with today and may not present with next month, and prescribes to that pattern.

Sasang diagnoses the person. The constitution is held to be fixed for life, and treatment aims to manage its inherent imbalance rather than to correct a transient state. The consequence is sharp: a herb or a food appropriate for one constitution may be actively harmful to another, so identifying the type correctly is the central clinical act, before any question of symptoms.

Lee Je-ma also made emotional disposition physiologically causal rather than merely associated. Sorrow, anger, joy and calm are each tied to a type, and their excess is a mechanism by which disease arises. That move sits inside the Joseon debate about the four beginnings and the seven emotions, which is one reason Sasang reads as a product of Korean philosophy as much as of medicine.

Its standing today

This is the part usually got wrong in English-language writing about the Changes. Sasang is not a historical curiosity or a folk practice. It is a required subject in Korean medicine degree programmes, a recognised clinical specialty with its own academic society and journals, and a routine part of practice in Korean clinics.

Since the 1990s Korean research groups have worked on two problems. The first is reproducibility: because typing depends on the practitioner's judgement of build, voice, temperament and response, different clinicians could type the same patient differently, so standardised questionnaires such as the QSCC instruments were developed. The second is whether the four types correspond to anything measurable, with association studies looking at genetic, metabolic and anthropometric markers.

The honest summary of that second programme is that results are mixed and nothing is established. Studies are often small, findings do not consistently replicate, and the typology has not been validated in the way its proponents hoped. That is a real limitation and it is worth stating plainly.

What is actually being claimed

It is worth separating three things.

That the Book of Changes supplied the framework is straightforwardly true and documented: Lee Je-ma says so, and the four images are the structure.

That the system is clinically institutionalised in Korea is also true and easily checked.

That the four constitutions correspond to biologically real categories is a further claim, and it is the one that has not been demonstrated. A reader can hold the first two without the third.

The system's own logic supplies a practical caution as well. If a remedy correct for one type can harm another, then typing yourself from a magazine questionnaire and prescribing yourself herbs is precisely the use the framework warns against.

The Juyeok school page covers the wider Korean intellectual tradition Sasang grew out of, in which the Changes was the working vocabulary of philosophy for five centuries.

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