You can cast the I Ching online here, free: open the I Ching casting tool, hold one honest question in mind, and press cast. Six virtual coin throws build your hexagram from the bottom line up, using the three-coin method. The tool marks any changing lines, shows the resulting hexagram they produce, and links each hexagram to its full page on this site. You can also save the cast as a link and return to it later.
The I Ching (易经 Yì Jīng, the Book of Changes) is a tool for reflection, not prophecy. The rest of this page explains what the tool is doing, so you can read what it gives you.
Before you cast: asking a good question
The quality of a reading depends heavily on the question. In practice, the questions that work share three traits.
- One question, one situation. “Should I take the new role, and what about my relationship?” is two casts.
- Open, not yes or no. “What should I understand about taking this role?” gives the text something to answer. A bare yes or no rarely fits the way hexagrams speak.
- About your own conduct. The book speaks to how you meet a situation. It is weakest when asked to predict what someone else will do.
Write the question down before you cast, and cast once. Recasting until you like the answer is the classic mistake; it turns a mirror into a slot machine.
How the three-coin method builds a hexagram
Each line comes from a toss of three coins. Heads counts 3 and tails counts 2, so the three coins always add up to 6, 7, 8 or 9.
| Coins | Sum | Line | Changing? |
|---|---|---|---|
| Three tails | 6 | Yin (broken) | Yes, becomes yang |
| One head, two tails | 7 | Yang (solid) | No |
| Two heads, one tail | 8 | Yin (broken) | No |
| Three heads | 9 | Yang (solid) | Yes, becomes yin |
Six tosses give six lines, written from the bottom up: the first toss is line 1 at the base, the sixth is line 6 at the top. The lower three lines form one trigram and the upper three another, and a hexagram is always named as the upper trigram over the lower. There are eight trigrams (八卦 bā guà), so 64 possible hexagrams, each with its King Wen number. The eight trigrams guide covers the building blocks, and I Ching casting methods compares coins with the yarrow-stalk method.
Reading your cast: primary, changing lines, resulting
A reading has up to three parts, and the I Ching online tool shows all of them.
1. The primary hexagram
This is the hexagram as cast, and it describes the situation as it stands. Read its overall meaning first, before any line. Every hexagram has its own page; the list of all 64 hexagrams is the index.
2. The changing lines
Any 6 or 9 is a changing line: the point where the situation is under tension and about to turn. These lines carry the most specific advice in a reading, so give them weight. When several lines change at once, schools differ on how to weigh them; I Ching changing lines sets out the approaches.
3. The resulting hexagram
Flip every changing line, yin to yang and yang to yin, and you get the resulting hexagram: where the situation tends if it runs its course. If no line changes, there is no resulting hexagram; the situation is stable, and you read the primary hexagram as it stands.
A worked example
Suppose the six tosses, bottom to top, come out 9, 8, 8, 8, 8, 8. The bottom line is yang and the five above it are yin. The lower trigram is Zhen (震 zhèn, Thunder) and the upper is Kun (坤 kūn, Earth): Kun over Zhen is hexagram 24, 復 fù, Return, the hexagram traditionally paired with the winter solstice. The bottom line was a 9, so it changes. Flip it to yin and all six lines are yin: Kun over Kun, hexagram 2, 坤 kūn, The Receptive. One reads Return, then the first line, then the Receptive as the direction of travel.
I Ching online or coins in hand: an honest note
The online cast follows the same arithmetic as three coins on a table: each virtual coin has an even chance of heads or tails, and the line values follow the same table. What changes is the ritual. Tossing real coins six times slows you down, and that pause is where much of the value lies, because it keeps the question in front of you. If you are comparing tools, we set out what a good I Ching caster needs, from coin-line casting to changing lines.
So use whichever lets you ask more honestly. If you cast the I Ching online, take the same care: a quiet minute, the question written down, one cast. If you own three coins, the table above is all you need to cast by hand and check the result against the hexagram pages. For the reading method in depth, see how to read the I Ching, and for the book’s background, the I Ching hub.
Cast your hexagram
The book works best on decisions you are actually facing. Cast your hexagram now with the free I Ching tool. When a decision carries real weight and you want it read alongside your Ba Zi chart, book a reading: one hour, chart on the table, a written summary, and no fear-selling.