What is the I Ching?
The I Ching (also written Yijing) means the "Book of Changes". It is a Chinese text used for divination (seeking guidance by a chance method) and studied as a work of philosophy. Its central idea is that everything is always changing, and that wisdom means understanding the pattern of change and acting in tune with it.
It is one of the oldest books still in use anywhere. For over two thousand years it has influenced Chinese thought, from Confucian and Daoist philosophy to medicine, art and government.
Roots in early China
Long before the I Ching, rulers of the Shang dynasty (around 1600 to 1046 BCE) asked questions of their ancestors by heating animal bones and turtle shells until they cracked, then reading the cracks. Many of these "oracle bones" survive, with the questions and answers carved into them. They are some of the earliest Chinese writing we have.
The I Ching came from a different method, using counted plant stalks and numbers. Its oldest layer is called the Zhouyi ("Changes of Zhou"), after the Zhou dynasty. Scholars generally date this core text to the Western Zhou period, roughly 1000 to 750 BCE. Tradition credits it to legendary and royal figures, such as Fu Xi and King Wen, but historians see it as a text that grew over time.
A layered book
The I Ching has several layers, written at different times:
- The hexagrams. 64 figures, each with a name.
- The judgements. A short text for each hexagram.
- The line statements. A short text for each of the six lines in each hexagram.
- The Ten Wings. Commentaries added later, probably during the Warring States and early Han periods. Tradition credits them to Confucius, but most scholars think they were written by later followers.
The Ten Wings changed how the book was read. They explained it in terms of yin and yang, cosmic order and good conduct. Under the Han dynasty (from 206 BCE) the I Ching became one of the official Confucian classics, studied by scholars for centuries.
Archaeology keeps adding to the story. A copy written on silk was found in a tomb at Mawangdui, sealed in 168 BCE. It puts the hexagrams in a different order from the version used today, which shows that the text was not always fixed.
How the hexagrams work
Lines
Everything in the I Ching is built from two kinds of line:
- a solid line, called yang: active, firm, bright
- a broken line, called yin: receptive, yielding, dark
Trigrams
Three lines stacked together make a trigram. There are eight possible trigrams, and each is linked to an image from nature: Heaven, Earth, Thunder, Water, Mountain, Wind, Fire and Lake.
Hexagrams
Two trigrams stacked make a hexagram of six lines. Since each line can be one of two kinds, there are 2 x 2 x 2 x 2 x 2 x 2 = 64 hexagrams. Lines are always counted from the bottom up.
Each hexagram has a name and a theme. Hexagram 1 is all solid lines and is called The Creative. Hexagram 2 is all broken lines and is called The Receptive. Hexagram 63, After Completion, is followed by 64, Before Completion, which ends the book on an open note: change never stops.
Centuries later, the German thinker Gottfried Leibniz noticed that the hexagrams could be read as binary numbers, the same 0-and-1 system computers use today. He wrote about this in the early 1700s.
Changing lines
When you consult the I Ching, each line is not just yin or yang. It is one of four kinds, given a number from 6 to 9:
- 6, old yin: a broken line that is changing into a solid one
- 7, young yang: a stable solid line
- 8, young yin: a stable broken line
- 9, old yang: a solid line that is changing into a broken one
The "old" lines are called changing lines. If you get any, you read their line statements, then flip them to make a second hexagram. The first hexagram shows the present situation. The second shows where it is moving.
Two ways to cast
The yarrow-stalk method
The traditional method uses 50 dried stalks of the yarrow plant. One is set aside, and the other 49 are divided, counted off in fours and set aside again in a slow, careful process. It takes three rounds of this to make one line, so a full hexagram can take quite a while. Many people value it as a kind of meditation.
The process produces uneven odds. Out of every 16 lines, on average you get 1 old yin (6), 5 young yang (7), 7 young yin (8) and 3 old yang (9). So changing yang lines turn up three times as often as changing yin lines.
The three-coin method
A quicker method, used since at least the Song dynasty, is to toss three coins. One side counts as 3 and the other as 2, and the total of the three coins gives 6, 7, 8 or 9. Here the odds are even between yin and yang: out of every 8 lines, on average 1 is old yin, 3 are young yang, 3 are young yin and 1 is old yang.
Both methods are traditional. They just give the changing lines slightly different chances.
Asking a question
People who use the I Ching usually suggest asking open questions, like "What should I understand about this decision?" rather than yes or no questions. The answers are short and poetic, full of images like "crossing the great water" or "the well". Their meaning comes from thinking about how the image fits your situation.
What the I Ching is, and is not
- It is a major work of world literature and philosophy, with a long and well-documented history.
- Its casting methods are real procedures with exact probabilities, which our tool reproduces.
- There is no scientific evidence that a cast hexagram predicts what will happen. Its value for most modern readers is as a prompt to think carefully about change, timing and the way they act.
- Translations differ a great deal. If a reading feels unclear, it can help to compare more than one.
It also deserves respect as part of Chinese intellectual and cultural history. Learning about where it came from adds depth to any reading.
Try it
Our I Ching hexagram generator lets you cast with either the yarrow-stalk odds or the three coins, shows any changing lines and the second hexagram, and explains each step. If you enjoy chance-based reflection, you might also like casting runes.