How a reading is built
Nothing on this page is interpretation. It is the arithmetic. Once you have read it once, you can look at any reading in this app and say exactly where every part of it came from.
1. Three coins make one line
Each coin is worth 2 or 3. Three coins are thrown together and their values added, so a line is always 6, 7, 8, or 9. You throw six times, and the first throw is the bottom line.
| Value | Name | Coins | Now | On change |
|---|---|---|---|---|
| 6 | Changing yin | 2 + 2 + 2 | yin | becomes yang |
| 7 | Stable yang | 2 + 2 + 3 | yang | stays yang |
| 8 | Stable yin | 2 + 3 + 3 | yin | stays yin |
| 9 | Changing yang | 3 + 3 + 3 | yang | becomes yin |
Because there are more ways to add up to 7 or 8 than to 6 or 9, stable lines are three times as likely as changing ones. A 6 or a 9 has a 1 in 8 chance; a 7 or an 8 has 3 in 8.
The yarrow stalks are not the same
The older method divides forty-nine stalks three times per line and counts the heaps off in fours. It is not the coin method with different props: it produces a different distribution, and this app carries out the procedure rather than relabelling a coin toss.
| Value | Three coins | Yarrow stalks |
|---|---|---|
| 6 | 2 in 16 | 1 in 16 |
| 7 | 6 in 16 | 5 in 16 |
| 8 | 6 in 16 | 7 in 16 |
| 9 | 2 in 16 | 3 in 16 |
With coins a changing yin and a changing yang are equally likely. With yarrow a changing yang is three times as likely as a changing yin. Which method you use changes what you are likely to see, which is why a saved reading records the one you chose.
2. Three lines make a trigram
Only the polarity matters here, not whether the line is changing. Lines 1 to 3 form the lower trigram and lines 4 to 6 the upper one. There are eight possible combinations.
乾 qián
Heaven · Initiating
Father · bits 111 bottom to top
兌 duì
Lake · Open
Youngest daughter · bits 110 bottom to top
離 lí
Fire · Clinging
Middle daughter · bits 101 bottom to top
震 zhèn
Thunder · Arousing
Eldest son · bits 100 bottom to top
巽 xùn
Wind · Penetrating
Eldest daughter · bits 011 bottom to top
坎 kǎn
Water · Deep
Middle son · bits 010 bottom to top
艮 gèn
Mountain · Still
Youngest son · bits 001 bottom to top
坤 kūn
Earth · Yielding
Mother · bits 000 bottom to top
3. Two trigrams make a hexagram
Each of the 64 upper and lower pairs has a number in the King Wen sequence, the traditional ordering. That number is looked up in a fixed table. It is not computed from the bits, and there is no formula for it: the sequence is a received ordering that has to be checked against sources, which is why this app keeps a verification note for it.
4. Changing lines make a second hexagram
Flip every changing line and leave the rest alone: a 6 becomes yang, a 9 becomes yin. Look the result up in the same table and you have the transformed hexagram. It is a derived fact about the same six throws, not a prediction about later.
What to do when several lines change is a real disagreement between traditions, not a settled rule. Rather than pick one and present it as law, this app treats a convention as something named and selectable.
Show every changing line
Every changing line is shown in bottom-to-top order. No line is ranked above another.
Deliberately unsourced: it encodes no interpretive claim.
Zhu Xi (Yixue Qimeng)
Rules from Zhu Xi's Introduction to the Study of the Changes (c. 1186). The reading method changes with the number of changing lines: one reads that line, two read both with the upper prioritised, three read the Judgements of both hexagrams, four read the non-changing lines of the transformed hexagram, five read the single non-changing line, six read the transformed Judgement.
Zhu Xi, Yixue Qimeng (易学啟蒙), c. 1186. English: Joseph A. Adler, Introduction to the Study of the Classic of Change, Global Scholarly Publications, 2002.
Huang (governing line)
Alfred Huang's method: each hexagram has a governing line (the host) that carries its central theme. When multiple lines change, the changing line that occupies the host position is shown first. If none of the changing lines is the host, all are shown in bottom-to-top order.
The host of a hexagram is Alfred Huang's teaching, set out in The Numerology of the I Ching (Inner Traditions, 2000). The 64-entry table used here is transcribed from the Wikibooks I Ching compilation, en.wikibooks.org/wiki/I_Ching/Host_Of_The_Hexagrams (CC BY-SA), not from Huang's books directly.
5. Where the words come from
Every block of text in a reading is labelled with its layer, so you never have to guess what you are reading.
- Source text
- The received Chinese text, in a stated edition.
- Translation
- A named translator’s words, with the edition and licence.
- Commentary
- Attributed historical or modern commentary.
- Our explanation
- Written by this project. Carries no scholarly authority, and is never presented as a translation.
- AI reflection
- Model-generated, always optional, always last, and only ever written against passages that are already on the page.
Where a reading says source text has not been imported, that is literal. Showing remembered or generated text in its place would defeat the point of the labels.
6. The book, and what was written about it
Two different things travel under the name I Ching, and a reading shows you both.
- Zhouyi 周易
- The base text, and the older of the two: a judgement for each hexagram, a statement for each line, and the Great Image. This is what the app labels source text.
- The Ten Wings 易傳
- Commentary that grew up around the Zhouyi and that the tradition came to transmit alongside it, turning a divination manual into a philosophical classic. Tradition attributes it to Confucius; the scholarship does not. The app records that as a traditional attribution rather than an author.
Three of the wings attach to something you can point at, and those are the ones a reading shows. The 彖傳 comments on a hexagram’s Judgement and sits under it. The 小象 comments on a single line and sits under that line. The 文言 exists only for the first two hexagrams and is long enough to stand on its own.
The 大象 is the exception: it is a wing, but the received text carries it inline for every hexagram, which is why it appears as the Image rather than as commentary. The remaining wings — the 繫辭, 說卦, 序卦 and 雜卦 — are treatises about the whole book and attach to no particular hexagram, so they are not imported.
Legge translated all of it. His English of a wing is labelled translation rather than commentary, because a translation of commentary is still a translation: the commentary is the Chinese it renders, and that is on the page beside it.
Try it
Cast a reading and every step above is shown for your own six throws.
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