Casting the I Ching
How to throw the coins, build a hexagram, and read what the changing lines tell you.
The building blocks
A hexagram is six stacked lines. Each line is either yang (solid ▬▬▬) or yin (broken ▬ ▬). That binary distinction is the entire vocabulary.
Three stacked lines make a trigram. Eight combinations are possible — Heaven (☰), Earth (☷), Water (☵), Fire (☲), Mountain (☶), Lake (☱), Thunder (☳), and Wind (☴).
Two trigrams stacked make a hexagram: 8 × 8 = 64 combinations. Here is Hexagram 13 — Fire (☲) below Heaven (☰), called Tóng Rén or "Fellowship with Others". Once you can read the trigrams, you can read any hexagram. Browse them all at /hexagrams.
The three-coin method
The coin method is the practical successor to the older yarrow-stalk procedure. It gives a slightly different probability distribution but is far quicker, and is the standard contemporary technique.
What you need
Three coins of the same denomination. Traditionally Chinese cash coins are used (round with a square hole) but any three identical coins work. You will throw them six times.
Assign values to each face
Before you start, decide which face counts as 3 and which as 2. The conventional assignment is:
- Heads (or, on a cash coin, the inscribed side) = 3
- Tails (or, on a cash coin, the blank side) = 2
Either assignment works — just be consistent throughout the reading.
Throw the coins and sum the values
Hold all three coins, focus on your question, and throw them. Sum the three values. The total will always be 6, 7, 8, or 9. That sum tells you which kind of line you've just generated:
| Sum | Line | Glyph | Meaning |
|---|---|---|---|
| 6 | Old yin | ▬ ▬ ⊗ | Broken line, changing — about to flip to yang. |
| 7 | Young yang | ▬▬▬ | Solid line, stable. |
| 8 | Young yin | ▬ ▬ | Broken line, stable. |
| 9 | Old yang | ▬▬▬ ⊗ | Solid line, changing — about to flip to yin. |
Build the hexagram from the bottom up
Throw the coins six times. The first throw gives you the bottom line (line 1). Each subsequent throw stacks above the previous one. The sixth throw gives you the top line (line 6). The completed figure of six stacked lines is your primary hexagram.
Look it up in the index of 64 hexagrams by reading the lines bottom-up.
Changing lines
Any line you threw as a 6 (old yin) or a 9 (old yang) is a changing line. It carries extra energy and is in the process of flipping to its opposite.
To find the resulting (or relating) hexagram, flip every changing line — old yin becomes young yang, old yang becomes young yin — and read the new figure. This second hexagram represents the direction the situation is moving toward.
Worked example
Hex 13 · Tóng Rén
Fellowship
Line 5 flips
old yang (9) → young yin (8)
Hex 30 · Lí
The Clinging
Throw the coins six times
Following the convention heads = 3, tails = 2:
- Line 1 (bottom): H T T = 7 → young yang
- Line 2 : T H H = 8 → young yin
- Line 3 : H T T = 7 → young yang
- Line 4 : H T T = 7 → young yang
- Line 5 : H H H = 9 → old yang ⚡
- Line 6 (top) : H T T = 7 → young yang
Read off the primary hexagram
The six lines you've built, reading bottom to top, are Hex 13 · Tóng Rén (Fellowship) — Fire below Heaven.
Find the resulting hexagram
Line 5 came up as a 9, so it's a changing line. Flip it (yang ⟶ yin) and the new figure is Hex 30 · Lí (The Clinging) — Fire above Fire. That's the direction the situation is moving: fellowship intensifying into shared illumination.
A reading with no changing lines describes a stable situation; the primary hexagram's overall judgment applies as-is. A reading with one or more changing lines tells a story of motion — and the next section explains which line texts to focus on when there's more than one.
Three styles of reading the changing lines
All three traditions agree that every changing line flips to produce the resulting hexagram. They disagree on which line texts to read for guidance when more than one line is changing. This app supports all three:
| Modern | Chu Hsi | Master Yin | |
|---|---|---|---|
| Origin | Contemporary practice | Zhu Xi, 12th c. | Master Yin (via Alfred Huang, 1998) |
| Approach | All changing lines as narrative | Rule by line count | Rule by line count + yin/yang priority |
| Best for | Layered, holistic reading | Single decisive answer | Single answer with yin/yang sensitivity |
Modern (default)
Read all changing line texts together as a narrative, then consider the resulting hexagram as the direction of change. The most common contemporary approach — it treats the changing lines as a layered story rather than isolating a single line.
Best for: readings where you want the fullest picture and are comfortable holding multiple threads of meaning at once.
Chu Hsi (classical)
Codified by the 12th-century Neo-Confucian scholar Zhu Xi. The number of changing lines determines what to read:
- 1 line: read that changing line.
- 2 lines: focus on the upper changing line.
- 3 lines: read the judgments of both the primary and resulting hexagrams.
- 4 lines: focus on the lower of the two non-changing lines.
- 5 lines: focus on the single non-changing line.
- 6 lines: read the judgment of the resulting hexagram.
Worked example
You cast Hex 11 (Peace) with changing lines in positions 2 and 5. Under Chu Hsi, you read the upper changing line (line 5) and consider Hex 26 (Great Taming) as the direction the situation is moving.
Master Yin
Attributed to Master Yin and documented by Alfred Huang in The Complete I Ching (1998). Similar to Chu Hsi but with yin/yang priority rules for selecting the key line:
- 1 line: read that changing line.
- 2 lines: if one is yin and one yang, read the yin line. If both are the same type, read the lower one.
- 3 lines: read the middle changing line.
- 4 lines: focus on the lower non-changing line.
- 5 lines: focus on the single non-changing line.
- 6 lines: read the judgment of the resulting hexagram.
Worked example — where Master Yin diverges from Chu Hsi
Suppose two changing lines: line 2 is yang and line 4 is yin. Chu Hsi reads the upper one (line 4). Master Yin also reads the yin one — same line here, but had line 2 been the yin one (and line 4 the yang), Master Yin would read line 2 while Chu Hsi would still pick line 4.
How to choose between them
- Modern — pick this if you want the fullest picture and don't mind holding multiple threads.
- Chu Hsi — pick this if you want classical authority and a single decisive line.
- Master Yin — pick this if you want a single line chosen by yin/yang balance rather than purely by position.
In the app you can pick a style per reading when you cast, or set your default in Profile → Preferences.