The canon
五行
The five phases — wood, fire, earth, metal and water — are Chinese medicine’s map of how the parts of a whole affect one another. Two cycles run through them: sheng, in which each phase generates the next, and ke, in which each phase restrains a second. Every phase carries a season, an organ pair, a flavour, a colour and a climate.
The word
Wǔxíng is usually printed in English as the five elements, which quietly hands the reader the wrong book. The Greek elements are substances: earth, air, fire and water are what the world is made of, and a thing is a mixture of them. 行 is not a substance. It is a going, a course, a phase — the same character as in 行走, to walk. The five are stages a process passes through, each named after the clearest everyday instance of that stage.
Read that way the scheme stops being mystical and starts being ordinary. Wood is the phase in which things push outward and upward: spring, morning, the first surge of an effort. Fire is the top of the arc. Earth is the turn, the settling, the digesting. Metal is contraction and sorting, autumn, the breath. Water is the bottom of the year, storage, the part nobody sees. Anything with a rise and a fall can be described in five stages, and this is a set of names for them.
The list is older than medicine. Its earliest surviving statement is a chapter of the Book of Documents called the Great Plan, in which each of the five gets a one-line description of what it does — water soaks and descends, fire flames upward, wood bends and straightens — and a flavour attached to it. Salt for water, bitter for fire, sour for wood. Those flavour pairings are still in the table lower down this page, unchanged, two and a half thousand years later.
The two cycles
What makes the five phases a working scheme rather than a list of five words is that they are wired to each other twice, in two different shapes, at the same time.
Around the rim, each phase produces the next. Water feeds wood; wood feeds fire; fire, burning down, makes earth; earth yields metal; metal, in the classical image, gathers water on its cold surface, and the ring closes. This is the cycle of supply. Read backwards it is a cycle of dependency: if fire is thin, the tradition asks first whether wood is feeding it.
Across the middle, each phase checks the one two steps on, which draws a five-pointed star inside the circle. Water puts out fire; fire melts metal; metal cuts wood; wood breaks up earth; earth dams water. This is the cycle of limit, and it is the more interesting half. A system with only generation runs away from itself. The star is what keeps the ring from becoming a spiral.
Restraint can go wrong in exactly two ways, and the tradition names both. Overwhelming, 乘, is restraint pressed too hard, so the checked phase is flattened instead of held. Rebellion, 侮, is restraint running backwards, so the phase that ought to be checked pushes back against the one checking it. Neither is a new force. Both are the same two arrows, out of proportion.
East gives rise to wind; wind gives rise to wood; wood gives rise to the sour; the sour gives rise to the liver.
Correspondence
Chapters four and five of the Suwen do something the earlier texts had not: they run the five phases across a set of columns and fill in the whole grid. Each phase collects a compass direction, a season, a climate that belongs to that season, an organ pair, a flavour, a colour, a sound, an emotion, a grain and a domestic animal. Later writers added more columns; the medical core has stayed the same since the Han.
The grid is what makes the scheme portable. Once wood, spring, wind, the liver network, sourness and the colour 青 are filed in the same row, a physician can enter the row from any column — from a season, from a flavour, from something a person says about their temper in March — and arrive at the same place. That is not a proof of anything. It is a memory that holds relationships, and it is what the diagram below is drawing.
Two cycles
Move to a phase, or tab to one, and its two relationships light: the phase it generates and the phase it restrains. The full table is printed below, and it says the same thing without the drawing.
This table is the page. The drawing above is a way of looking at it, and everything the drawing says is said here, in text, whether or not a browser ever runs it.
| Phase | Season | Organ pair | Flavour | Colour | Climate | Direction | Generates | Restrains |
|---|---|---|---|---|---|---|---|---|
| Fire | Summer | Heart · Small intestine | Bitter | 赤 red | Heat | South | Earth | Metal |
| Earth | Late summer | Spleen · Stomach | Sweet | 黄 yellow | Damp | Centre | Metal | Water |
| Metal | Autumn | Lung · Large intestine | Pungent | 白 white | Dryness | West | Water | Wood |
| Water | Winter | Kidney · Bladder | Salty | 黑 black | Cold | North | Wood | Fire |
| Wood | Spring | Liver · Gallbladder | Sour | 青 green | Wind | East | Fire | Earth |
What it is not
It is worth being blunt about this, because a diagram with arrows in it invites a reader to think it is a causal model. It is not one. Nothing physical passes from the kidney network to the liver network when the tradition says water feeds wood. The five phases are an analogy carried out consistently, and their value is that consistency: they keep a physician thinking about a body as a set of relationships rather than a set of parts.
The scheme was also applied to almost everything else. Dynasties claimed a phase and dressed their court in its colour. Musical notes, grains, planets, numbers and offices of state were all filed into the same five columns. Some of that is careful observation and some of it is Han-dynasty administrative tidying, and Chinese physicians have been arguing about which is which since at least the eleventh century.
So we use it the way the practice uses it — as an index rather than an explanation. It tells you which questions belong near each other. If your sleep, your temper and your digestion all shift in the same fortnight of spring, the five phases are the reason a Chinese physician reads those three answers as one observation instead of three.
In a reading
The five phases sit underneath a reading rather than on top of it. They are why a food note says sour or sweet instead of naming a nutrient: flavour is a column in the grid, and it is the column a kitchen can act on. They are why a report written for you in January would not be the same document in July — season is another column, and the Suwen’s seasonal chapters are explicit that the same person is a different proposition in winter.
They are also why the organ names in a pattern description are capitalised. The Liver of the five phases is a row in a table — spring, wind, sour, green, the free movement of qi — and not the organ a scan photographs. Keeping the capital letter is the smallest honest way of saying so on every line.
And they are why three unrelated-sounding answers can end up in one paragraph. The grid puts a season, a temper and a digestion in the same row, so a physician reading your thirty answers has a reason to read those three answers as one observation rather than three. How a reading is made sets out what happens between your answers and that paragraph.
Questions
Because 行, xíng, means a course or a going, not a substance. The Greek elements are what things are made of; the Chinese five are stages a process moves through, named after the most legible example of each. Wood is not lumber. It is the phase of a year, a day or a body in which things push outward.
Sheng, 生, generation: each phase feeds the next around the rim — water feeds wood, wood feeds fire, fire feeds earth, earth feeds metal, metal feeds water. Ke, 克, restraint: each phase checks the one two steps on, drawing a five-pointed star inside the circle — water checks fire, fire checks metal, metal checks wood, wood checks earth, earth checks water.
The tradition names two failures. Cheng, 乘, overwhelming, is restraint pressed too hard, so the checked phase is flattened rather than held. Wu, 侮, insulting, is restraint running backwards, so the phase that should be checked pushes back against the one checking it. Both are ways of saying a relationship has gone out of proportion.
No, and we do not present it as one. It is a filing system built from analogy: a way of holding correspondences between a season, an organ network, a flavour and a colour so that a physician can move between them. It is useful because it keeps relationships in view, not because it explains a mechanism.
Mostly quietly. The flavour column is why a food note says sour or sweet rather than naming a nutrient. The season column is why a report written in January differs from one written in July. The organ pairs are the vocabulary the pattern description uses. You will rarely see the diagram itself; you will see its filing.
The reading
A reading uses this grid the way a physician does — as the index that decides which of your thirty answers belong in the same paragraph — and then writes the result in plain English.