I Ching, Yijing, Zhouyi, Book of Changes: why so many names?

They are all names for the same book, seen from different angles. I Ching and Yijing are two romanisations of 易經, "the Classic of Changes": the first in the older Wade–Giles system, the second in modern pinyin. Zhouyi (周易, "the Changes of Zhou") is the name of the original divination text at its core. Book of Changes is an English translation of the title, and Yi King and I Ging are older French and German spellings.

The useful distinction is not between spellings but between two things the names can point to: the bare Zhou-dynasty text, and the classic that grew around it.

Zhouyi: the core text

The Zhouyi is the oldest layer. It contains the 64 hexagrams, each with a name, a short Judgment (卦辭) and six line statements (爻辭) — plus the two extra texts for all-yang and all-yin lines under Qian and Kun. That is all. It is terse, full of omens and images, and it was used for divination at the Zhou court; the Zuozhuan records officials consulting it.

Why "Zhou"? The usual answer is the dynasty: this was the Changes of the Zhou, as distinct from two other divination books that tradition attributes to earlier dynasties, the Lianshan (連山) and the Guicang (歸藏). The Rites of Zhou (周禮) names these "three Changes" (三易). A minority reading, going back to Han commentators such as Zheng Xuan, takes 周 in its sense of "all-round, encompassing". Most modern scholars favour the dynastic reading. See Lianshan, Guicang and Zhouyi for what is known about the other two.

Yijing: the classic with its commentaries

易經 adds the word jing (經), "classic" or "canonical text". It marks the book's status after it was adopted as one of the Five Classics in the Han dynasty, when the Zhouyi was read together with a set of commentaries known as the Ten Wings (十翼): the Tuan, the Images, the Great Commentary (Xici), the Wenyan and the rest. Tradition attributed the Wings to Confucius; modern scholarship sees them as the work of several hands from the Warring States into the early Han (see Confucius and the I Ching).

So, strictly:

• Zhouyi — the 64 hexagrams with their Judgments and line statements.
• Yijing / I Ching — the Zhouyi plus the Ten Wings, as a canonical classic.

In everyday use the line is blurred. Chinese speakers say 周易 and 易經 almost interchangeably, and the great commentaries use both: Wang Bi's is called 周易注, Zhu Xi's 周易本義, Cheng Yi's commentary circulated as 易傳. When scholars want to be precise, they say Zhouyi for the early text and Yijing for the classic.

The single character 易 (yi) is also used on its own, as in "studying the Yi". Han commentators said this one word held three meanings — ease or simplicity, change, and constancy (易簡、變易、不易) — a formula Zheng Xuan repeated and later writers often quote. It is an interpretation rather than an etymology, but it captures how the tradition understood the book: a simple pattern, always changing, governed by something that does not change.

Romanisation: I Ching, Yijing, Yi King, I Ging

The sounds are the same; the spelling systems differ.

• I Ching — Wade–Giles, the system most English books used before pinyin. I is the syllable "yi" and Ching is "jing". It became the standard English title through the Wilhelm–Baynes translation, published in 1950 as The I Ching or Book of Changes.
• Yijing (or Yi Jing) — Hanyu Pinyin, the official romanisation of the People's Republic of China, now usual in academic writing. It is also the best guide to pronunciation: roughly "yee jing", with the second syllable like the j in "jeep".
• Yi King — older French-style spelling, also used by James Legge, whose 1882 English translation was titled The Yî King.
• I Ging — the German spelling, from Richard Wilhelm's I Ging: Das Buch der Wandlungen (1924), the translation behind the 1950 English version.
• Book of Changes — a translation, not a transliteration; "Classic of Changes" is a more literal rendering of 易經.

You will also see I-Ching, Yi-King and other variants; none of them points to a different book. Our site uses "I Ching" because it is what most English readers search for, and Zhouyi when the early text specifically is meant.

Why the names matter when you read

Knowing which layer you are reading changes how you weigh it.

• The Judgment and line statements are the Zhouyi: the oldest and most authoritative part of a reading. When you cast and read a changing line, you are reading this layer.
• The Image (大象, "the superior person, in accordance with this…") and the Tuan commentary are Ten Wings: later, moral and philosophical, and in practice indispensable for interpretation. See the Great and Small Image.
• Translations mix the layers differently. Wilhelm interleaves the Wings with the text; some modern translations print the Zhouyi alone. If two books seem to say different things about the same hexagram, check whether one is quoting a commentary.

Excavated manuscripts add one more twist. The silk text from Mawangdui, buried in 168 BCE, has the same hexagrams in a different order and with some different names. Those versions are still "the Changes", but they show that the text was not fixed in a single form from the start.

In practice

When you cast a reading in our I Ching tool, the hexagram page gives you the Zhouyi text first, then the commentaries, so you can tell the oldest words from the explanations around them. A good habit:

• Read the Judgment and the line as the core answer — that is the Zhouyi speaking.
• Read the Image as advice on conduct — that is the classic, the Yijing, speaking.
• When you look something up, do not worry about the spelling. I Ching, Yijing and Book of Changes will all lead you to the same 64 hexagrams; what matters is which layer of the text you are quoting. For the longer story of how the book travelled, see the history and translations of the I Ching.