What is the I Ching?

The I Ching — 易經, the Book of Changes — is the oldest book in the Chinese canon and, for most of its history, the one people consulted before making a decision. It is not a book of predictions. It is a book of situations, and the claim it makes is that the situation you are in right now is one of sixty-four, that the pattern has a shape you can see, and that seeing it changes what you do next.

What it is, in one page

Underneath the poetry the system is unusually tidy. Every line of a hexagram is either unbroken (yang — solid, active, light) or broken (yin — open, receptive, dark). Stack six of them and you get 2⁶ = 64 possible patterns. That is the whole inventory. Not 64 meanings invented by committee — 64 looks, each of which the tradition has spent three thousand years describing.

Group the six lines in threes and you get two trigrams, one above the other. There are only eight trigrams, and each one is a basic image: Heaven, Earth, Thunder, Wind, Water, Fire, Mountain, Lake. So every hexagram is a sentence with two words in it — Water over Mountain, Wind under Heaven — and the relationship between those two images is the reading.

This is why the I Ching reads differently from tarot. A tarot spread interprets symbols in relation to a question; the I Ching tells you which of a fixed set of structural situations you are in, and then lets the text speak. It is closer to a diagnostic chart than a deck.

Where it came from

The oldest layer of the book is the hexagram names and judgments, traditionally dated to the early Zhou dynasty — roughly three thousand years ago. A later layer, the Ten Wings, added the philosophical commentary that turned a divination manual into a cosmology. Confucian scholars folded it into the canon; in the twentieth century C. G. Jung wrote a famous foreword to Richard Wilhelm's German translation, arguing that the I Ching works through what he called synchronicity — meaningful coincidence rather than cause and effect. That foreword is the single biggest reason the book has a Western spiritual audience at all.

For our purposes the history matters for one practical reason: the text is layered, so "what it means" is a conversation across centuries, not a lookup. Good translations disagree. This site does not reproduce any one of them.

The structure of a hexagram

The six lines (爻)	Counted from the bottom up — line 1 is at the base, line 6 at the top. Position matters as much as value: line 5, the ruler's position, is read differently from line 1.
Lower trigram (下卦)	Lines 1–3. Usually read as the inner situation, the starting condition, what is inside the house.
Upper trigram (上卦)	Lines 4–6. Usually read as the outer situation, what is visible, what the world is doing.
Judgment (彖)	The hexagram's overall statement — the situation named and judged.
Image (象)	The poetic image the trigrams make, and the stance it suggests.
Line texts (爻辞)	Six short statements, one per line, only consulted if that line is moving in your cast.

Casting: coins and stalks

There are two traditional methods, and they do not have the same odds. This is not a detail — it is the most commonly faked part of online I Ching.

Each line is decided by a number from 6 to 9, and the number tells you both the line's value and whether it is moving.

Value	Line	Moving?	Three coins	Yarrow stalks
6	old yin — broken	yes ✕	1/8	1/16
7	young yang — solid	no	3/8	5/16
8	young yin — broken	no	3/8	7/16
9	old yang — solid	yes ○	1/8	3/16

Three coins, each worth 2 (tails) or 3 (heads), thrown together, sum to 6, 7, 8 or 9 with the probabilities above. Yarrow stalks require eighteen operations with fifty stalks and produce a flatter distribution — fewer moving lines, and yang more likely than yin. Which method you use changes how often the oracle gives you something in motion. Our online cast implements both honestly.

Full step-by-step: how to cast with three coins →

Changing lines

When a line comes up old — 6 or 9 — it is changing, and it flips into its opposite, producing a second hexagram. The first hexagram is the situation as it stands. The second is where the movement is heading. The changing lines themselves carry the most specific advice in the whole reading, which is why experienced readers go to them first when there are one or two.

Rough conventions, which you should treat as conventions and not law:

• No changing lines — read the hexagram as a whole. The situation is stable; act on the judgment.
• One changing line — that line is the reading. Read it, then the resulting hexagram as the direction of travel.
• Two or three — read them together, and weight the upper one.
• Four or more — the reading has shifted: read the second hexagram as the main statement, with the first as context.
• All six — the situation is being replaced entirely. Concentrate on the second hexagram. (The tradition reserves special language for the case of all six lines changing in hexagrams 1 and 2 — but the plain reading above is enough for practice.)

The eight trigrams

Learn these eight and you can read any hexagram's two-word sentence for yourself.

How to actually read one

1. Name the situation. Read the judgment and the plain-English summary. Ask whether it describes your circumstances accurately. If it does not, you probably asked the wrong question.
2. Look at the two trigrams. What is above, what is below — outer and inner. Most readings click here.
3. Read the moving lines, if any, in the conventional order above.
4. Note the second hexagram. It is the direction of travel, not a second verdict.
5. Write down what you are going to do. Then leave it alone. Recasting the same question tomorrow because you did not like the answer is the one thing the tradition unanimously tells you not to do.

What it is not

It is not a prediction of events, and it is not a substitute for professional advice. If you are making a medical, legal or financial decision, the I Ching can help you clarify what you actually want; it cannot tell you what is true about the world. Used that way — as a structured way to think about a situation you are already in — people have found it useful for three thousand years. Used as a slot machine, it is just a slot machine with better prose.

Where to go next

This page covers the system. These go deeper on one piece of it each.