1 Divination and Zhouyi readings

For readers interested in the Zhouyi, the yarrow-stalk method and the three-coin method are useful starting points. The former has a strong classical background; the latter is easier to perform. Divination has taken many forms, and there is insufficient statistical evidence to rank their popularity across all historical periods.

Casting a hexagram and interpreting it are separate tasks. Casting establishes the six lines and which ones change. Interpretive rules determine which hexagram and line statements to read and how to understand them. The same coin-casting procedure can be used with different interpretive systems.

This article explains traditional practices and ways of reading their texts. A divinatory result is not proof that an event must occur. Modern readers may use it to reflect on a situation, formulate questions, and organize possible actions, while checking decisions against real-world evidence.

2 Representative traditional and later methods

Turtle-shell and animal-bone divination: heat was applied to shells or bones, and the resulting cracks were interpreted as signs. Numerous Shang-period oracle bones survive. This practice did not simply consist of looking up the 64 hexagrams and 384 lines of the Zhouyi.

Yarrow-stalk divination: stalks are divided and counted to generate six lines, after which the relevant texts are read. The traditional Great Expansion procedure is closely connected with passages in the Appended Statements, although later interpretations of its operational details differ.

The three-coin method: three coins are tossed together six times to produce six lines. This is a casting tool; the use of coins alone does not identify the interpretive school being followed.

Six-line Najia divination: after casting, the hexagram is assigned stems and branches, relational categories, and subject and counterpart positions. Interpretation also considers the Five Phases, calendrical factors, and changing lines. This differs from a reading based primarily on the hexagram and line statements.

Plum Blossom Numerology methods: hexagrams may be derived from times, numbers, or observed events. Interpretation often draws on hexagram imagery, the ti–yong relationship, and the Five Phases. Different versions should be explained separately rather than combined without distinction.

Drawing oracle lots and casting divination blocks: lots are interpreted through their numbers and associated verses, while paired blocks are used according to temple conventions. These practices do not usually apply the 64 hexagrams and 384 lines directly, and procedures may vary between temples.

3 The basic yarrow-stalk procedure

The Appended Statements describes a total of fifty stalks, of which forty-nine are used. The following outlines a common later procedure; it does not imply that the method was identical in every historical period.

1. Prepare fifty yarrow stalks or equal-length counting sticks. Set one aside and begin with forty-nine.

2. Follow a specified version of the procedure: divide the stalks, set one apart, count in groups of four, and handle the remainders. Together these steps form one transformation. Apply the same remainder-handling rules consistently.

3. Three transformations produce one line, represented by 6, 7, 8, or 9. After completing a line, restart with forty-nine stalks for the next one.

4. Build the six lines from bottom to top. Eighteen transformations complete a hexagram. Here, transformation refers to a counting operation, not to a changing line in the resulting hexagram.

This is an introductory outline rather than a complete practical manual: it does not specify every division and remainder step. Anyone wishing to perform the method should first select a complete procedure and follow it consistently.

4 Casting three coins and the four line types

Conventions for assigning values to the two faces of a coin vary. This article uses an explicit example: face A is worth 2 and face B is worth 3. Identify the two faces before starting and keep the assignment unchanged for all six casts.

Toss all three coins together and add their values. The order of the coins does not matter. Record the first cast as the bottom line and the sixth cast as the top line.

The values 6 and 9 indicate changing lines; 7 and 8 indicate unchanging lines. For three fair, independent coins, the probabilities of 6, 7, 8, and 9 are 12.5%, 37.5%, 37.5%, and 12.5%, respectively—not 25% each. These probabilities describe the casting mechanism, not the reliability of a favorable or unfavorable prediction.

5 The initial and resulting hexagrams

The initial hexagram consists of the six lines as first cast. Lines with values of 6 or 9 are changing lines. Reverse the polarity of every changing line and leave the others unchanged to obtain the resulting hexagram. If no lines change, the figure remains the same.

Example: the values from bottom to top are 9, 7, 7, 7, 7, 7. All six initial lines are yang, so the initial hexagram is Qian. Only the bottom line changes, becoming yin. The resulting hexagram is Gou; the reading may be described as Qian changing to Gou.

The resulting hexagram provides imagery for interpretation; it is not a guaranteed future outcome. When several lines change, reverse all of them to obtain the corresponding resulting hexagram.

6 Selecting hexagram and line statements

The changing-line rules associated with Zhu Xi's Introduction to the Study of the Changes are frequently cited in later tradition. The following is an introductory summary, not a universal standard shared by all schools. In this context, the term tuanci in the traditional sources means the hexagram statement in the core text, not the Tuan Commentary among the Ten Wings.

Higher means closer to the top line, and lower means closer to the bottom line; these terms do not compare the numerical values 6 and 9. When four or five lines change, read the specified statements in the resulting hexagram, not at the same positions in the initial hexagram.

For the priority rule and all twenty combinations of three changing lines, see the supplement on three-coin casting and Zhu Xi’s rules.

Under this system, Qian's Use of the Nines applies when all six lines are 9, and Kun's Use of the Sixes applies when all six lines are 6. Merely obtaining Qian or Kun does not call for these special texts. Later interpreters also disagree about some selection rules.

7 How the Ten Wings support interpretation

First select the core text according to the chosen rules, then consult the relevant commentary. Pair a hexagram statement with its Tuan Commentary and a line statement with its Lesser Image Commentary. Consult the Greater Image for broader principles of conduct and self-cultivation. For Qian and Kun, the Commentary on the Words of the Text offers further discussion.

In the example of Qian changing to Gou, only the first nine changes. Read its statement, understood here as a hidden dragon for which action is not yet appropriate, and then the Lesser Image explaining the yang line's low position. Qian's Greater Image adds a broader principle of sustained self-improvement modeled on Heaven's vigor.

A modern analogy might ask whether further preparation is needed and which conditions remain unmet. This is a question prompted by the text, not proof that conditions are inadequate. Gather evidence before deciding whether to pause, conduct a trial, or proceed.

8 Principles for reading and practical use

Before casting, define the question, its time frame, and the available actions. Choose the casting method and text-selection rules in advance rather than switching rules after seeing a result.

Record all six values in bottom-to-top order and distinguish the initial hexagram, changing lines, and resulting hexagram. Recording only the hexagram name loses essential information about change.

In interpretation, distinguish the core text, the explanations in the Ten Wings, and your own modern analogy. Do not equate line positions rigidly with job ranks or treat the Sequence of the Hexagrams as a guarantee of the next event.

When planning action, identify assumptions to test, the next step, and a review date. Repeated casting until a preferred answer appears can reinforce prior expectations. Health, legal, and financial decisions should rely on relevant evidence and professional judgment.

9 Basic rules of three-coin casting

Product configuration: use three coins to cast the lines and Zhu Xi’s Yixue qimeng system to select the texts. These are separate procedures used together. This does not attribute coin casting to Zhu Xi or give it the same probabilities as yarrow casting.

Before casting, record one question and its time frame. Assign A = 2 and B = 3 on each coin, with images or labels identifying the faces. Do not assume that “heads” and “tails” have a universal assignment. Keep the assignment fixed throughout a reading.

Toss three coins together and add the upward-facing values. Repeat six times. Cast 1 becomes the bottom line, followed by lines 2–5 and finally the top line. Store values bottom to top; display the top line at the top of the diagram.

The original yin and yang lines form the initial hexagram. Reverse every 6 and 9 simultaneously, retaining 7 and 8, to obtain the resulting hexagram. If no lines change, the two hexagrams coincide and need only be displayed once.

For physical casts, if a coin stands on edge, leaves the agreed area, or cannot be read, recast all three and record the invalid attempt. This is a product convention. Do not recast a valid line merely because its result is unwelcome.

10 Zhu Xi’s rules for zero to six changing lines

This section follows the rules in the “Examining Changes in Divination” system of Yixue qimeng, with explanations from Yixue qimeng tongshi. [S1] It is a particular interpretive tradition, not a universal rule across all schools. Here, tuanci means the hexagram statement, not the Tuan Commentary among the Ten Wings.

“Higher” and “lower” refer to positions, numbered 1 at the bottom through 6 at the top. With two changes, prioritize max(changing positions). With four, prioritize min(unchanged positions), and read that statement in the resulting hexagram.

The Qian and Kun exceptions apply only when all six lines change: six 9s select Qian’s Use of the Nines, and six 6s select Kun’s Use of the Sixes. Store these as special statements, not as a seventh line.

Reading the core text with the Ten Wings

First show the selected core statements, labeling primary and companion readings. Link a hexagram statement to its Tuan Commentary and Greater Image; link a line statement to the Lesser Image for the same hexagram and position. Distinguish classical text, modern explanation, and translation. For four or five changes, the Lesser Image must also come from the resulting hexagram.

12 Data fields and decision logic

The following is a proposed implementation specification. Field identifiers are shared across languages. Record casting and interpretation versions separately so future rule changes do not rewrite historical readings. Interface translations must not drive the algorithm.

Algorithm: validate input → sum each cast → build the initial yin/yang pattern → locate 6s and 9s → flip all changing bits → look up both hexagram IDs → select texts by change count → attach commentary references. Use value % 2, where 1 is yang and 0 is yin, with the bottom line at the left of the string. A binary integer is not a King Wen ID.

Content model: Hexagram links guaci, tuanzhuan, and daxiang by ID. Line links yaoci and xiaoxiang by (hexagram_id, position). SpecialText stores use9/use6. Preserve classical text, locale, translation, source, and version. Require 64 unique patterns and 384 line positions, plus the two special statements.

For three changes, return both statements with priorities primary and companion, plus the combination index. Any generative AI explanation is supplementary and must not alter the cast or selected texts.