What Is the I Ching? The Book of Changes and How Hexagram Divination Works

The I Ching — Yi Jing, the Book of Changes — is one of the oldest books in continuous use anywhere on earth. It is at once a divination manual, a philosophical classic at the root of Chinese thought, and a literary object that has fascinated readers from Confucius (tradition says he wore out the binding of his copy three times) to Leibniz, who was struck by its binary structure, to Jung, who wrote the foreword to its most famous Western translation.

At its heart are sixty-four six-line figures: the hexagrams.

From cracked bones to sixty-four figures

Chinese divination begins with heat-cracked oracle bones in the Shang dynasty. The Zhou dynasty's method — casting yarrow stalks to build figures of lines — produced the core text of the I Ching roughly three thousand years ago: sixty-four hexagrams, each with a name, a judgment, and a short text for every line. Later generations wrapped the oracle in layers of commentary (the "Ten Wings," traditionally linked to Confucius's school), which turned a diviner's handbook into a book of philosophy about change itself.

How a hexagram is built

Every hexagram stacks six lines, each either solid — yang — or broken — yin. Two stacked sets of three lines (the eight trigrams: heaven, earth, thunder, wind, water, fire, mountain, lake) give each hexagram its imagery: water over fire, mountain above thunder, wind following wind.

The classical way to consult the oracle is to generate the six lines randomly, bottom to top. The yarrow-stalk method is slow and ceremonial; the popular method for centuries has been three coins: toss them once per line, and the combination of heads and tails yields yang or yin — and sometimes an "old" line, which brings us to the oracle's signature idea.

Changing lines: the book's deepest trick

Some casts produce changing lines — old yang about to flip into yin, old yin into yang. A reading then involves two hexagrams: the present situation, and the situation it is turning into, with the changing lines' texts as the hinge. This is the Book of Changes living up to its name: it never describes a frozen state, always a moment in motion.

Liuyao: the diviner's craft

On top of the classic text, Chinese practice built a technical divination method called liuyao (six lines). It assigns each line an earthly branch and element, marks the "self" and "responding" lines, and reads the relationships — which line generates or controls which — against the day's calendar. Where a philosophical reading contemplates the hexagram's imagery, a liuyao reading works the structure like a chart, traditionally for concrete questions: this deal, this journey, this decision.

Asking a good question

Tradition is opinionated here: ask one clear question at a time, sincerely meant, and don't re-ask because you dislike the answer. The oracle's texts are terse and imagistic — "crossing the great river," "the well needs lining" — and their usefulness lies in how a serious question refracts through them.

A mirror of change, not a machine of answers

Three millennia of use have not made the I Ching a scientific instrument: a coin toss cannot know your situation, and no hexagram determines an outcome. What the book actually offers is a structured way to think about change — a random image, a disciplined vocabulary, and your own reflection doing the real work. At ORACUL, I Ching readings are for entertainment and cultural reference only — not medical, legal, financial, or other professional advice, and never a basis for real decisions.

Have a question on your mind? Our liuyao page casts the coins, builds the hexagram with its changing lines, and reads it in the traditional vocabulary — free.