science

Sanpaku

Sanpaku is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Sanpaku rather than just read about it. In short: Sanpaku (三白; lit. 'three whites') or sanpaku gan (三白眼; Chinese: 三白眼; pinyin: Sānbáiyǎn; lit. 'three-white eyes') is a Japanese term referring to a person with visible sclera on three sides of their irises: the normal left and right, plus above or below. The term is most often used in English to refer to a folk belief whereby it functions as an omen or symptom in alternative medicine.

Key takeaways

Sanpaku belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Sanpaku to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Sanpaku from memory before moving on to harder problems.

Reference excerpt

Sanpaku (三白; lit. 'three whites') or sanpaku gan (三白眼; Chinese: 三白眼; pinyin: Sānbáiyǎn; lit. 'three-white eyes') is a Japanese term referring to a person with visible sclera on three sides of their irises: the normal left and right, plus above or below. The term is most often used in English to refer to a folk belief whereby it functions as an omen or symptom in alternative medicine. It was introduced into English in the mid-1960s by George Ohsawa as a condition supposedly cured by his macrobiotic method. In manga iconography, sanpaku eyes are used to make a character seem dangerous or threatening.

History According to traditional Chinese and Japanese face reading, the eye is composed of two parts, the yin (black, iris and pupil) and the yang (white, sclera). The visibility of the sclera beneath the iris is said to represent physical imbalance in the body, and is claimed to be present in alcoholics, drug addicts, and people who over-consume sugar or grain. Conversely, the visibility of the upper sclera is said to be an indication of mental imbalance in people such as psychotics, murderers, and anyone rageful. In either condition, it is believed that these people attract accidents and violence. In August 1963, George Ohsawa, an advocate for macrobiotics, predicted that President John F. Kennedy would experience great danger because of his sanpaku condition. In 1965, Ohsawa, assisted by William Dufty, wrote You Are All Sanpaku, which offers the following perspective on the condition:

For thousands of years, people of the Far East have been looking into each other's eyes for signs of this dreaded condition. Any sign of sanpaku meant that a man's entire system — physical, physiological and spiritual — was out of balance. He had committed sins against the order of the universe and he was therefore sick, unhappy, insane, what the West has come to call "accident prone". The condition of sanpaku is a warning, a sign from nature, that one's life is threatened by an early and tragic end. According to Ohsawa, this condition could be treated by a macrobiotic diet emphasizing brown rice and soybeans.

Illustrations

Worked examples

Example 1 — a first encounter with Sanpaku

Start with the simplest possible case. Write down what Sanpaku claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Sanpaku before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Sanpaku ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Sanpaku

In research: Sanpaku appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Sanpaku in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Sanpaku is common in secondary-school and first-year university syllabi. It links to neighbouring topics Chinese folklore, Eye, Japanese folklore, so understanding it makes those chapters shorter.
In everyday life: Look for Sanpaku outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Sanpaku in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Sanpaku means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Sanpaku out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Sanpaku in simple terms?

Why does Sanpaku matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Sanpaku?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Sanpaku.