Methods · 6 min read

I Ching Yarrow Stalk Method and Hands-on Practice with 49 Stalks

Yarrow stalks and three coins produce the same four line values, 6, 7, 8, and 9, but with different probabilities. Following the 49-stalk procedure helps you track each step of traditional practice and read the resulting values.

The Great Expansion procedure in the classical text

The Great Expansion procedure, or Dayan shifa, appears in the Great Treatise, Part One, chapter 9. It describes dividing stalks, taking one aside, counting in fours, and retaining remainders. Zhu Xi explains its practice in Introduction to the Study of the Changes and in the Stalk Divination Procedure appended to his Original Meaning of the Zhouyi. Distinguish the classical passage from the later practical explanation.

Begin with 50 stalks, set one aside unused, and work with 49 active stalks. Three changes make one line; six lines require 18 changes. Record the bottom line first and work upward. The text gives the operations symbolic meanings, while their arithmetic can still be followed step by step.

大衍之數五十，其用四十有九，分而為二以象兩，掛一以象三，揲之以四以象四時，歸奇於扐以象閏，五歲再閏，故再扐而後掛。

Dà yǎn zhī shù wǔ shí, qí yòng sì shí yòu jiǔ, fēn ér wéi èr yǐ xiàng liǎng, guà yī yǐ xiàng sān, shé zhī yǐ sì yǐ xiàng sì shí, guī jī yú lè yǐ xiàng rùn, wǔ suì zài rùn, gù zài lè ér hòu guà.

The Great Expansion has fifty as its number, with forty-nine in use. Divide them in two to represent the two powers; hold one apart to represent the three powers. Count by fours to represent the four seasons, and place the remainders between the fingers to represent an intercalary month. Five years have two intercalations, so gather remainders twice before holding one apart again.

Zhouyi, Great Treatise, Part One, chapter 9; wording here follows Zhu Xi's explanation of the procedure.

What happens during one change?

At the first change of each line, divide the 49 stalks into left and right bundles, then take one stalk from the right. Both bundles must still contain stalks to count. Count each in groups of four and keep its remainder. If it divides exactly, keep the final four as the remainder instead of recording zero.

Set aside the single stalk together with the two remainders. Combine what remains for the next change. Setting stalks aside simply removes them from the current count. Do not restore the total to 49 between changes of the same line. Start again with 49 only when beginning the next line.

How three changes produce 6, 7, 8, or 9

The first change removes 5 or 9 stalks, leaving 44 or 40. The second and third each remove 4 or 8. After three changes, only 24, 28, 32, or 36 stalks can remain. Divide that remainder by 4 to obtain the line value.

For example, remove 5 from 49 to leave 44, then 4 to leave 40, then 4 to leave 36. You have set aside 13 in total, and 36 / 4 = 9, old yang. Here 9 names the line type; it does not mean a ninth position in a six-line hexagram.

Why are the probabilities different from three coins?

In the ideal model following Zhu Xi's explanation, the first change removes 5 with probability 3/4 and 9 with probability 1/4. At each subsequent change, removing 4 or 8 has probability 1/2. A value of 6 requires removals of 9, 8, 8, giving 1/4 × 1/2 × 1/2 = 1/16. A value of 9 requires 5, 4, 4, giving 3/4 × 1/2 × 1/2 = 3/16.

Both yarrow and balanced three-coin casting give a moving line with probability 1/4 and a primary yang line with probability 1/2. The difference is within the moving types: yarrow's moving yang is three times as frequent as moving yin, while coins give equal shares. Line probabilities describe how the cast is generated, not how likely your situation is to turn out a particular way. They do not establish the reliability of an interpretation.

Practice with physical stalks or counting sticks

Prepare 50 yarrow stalks or counting sticks, along with paper and a pen. Set one aside and use the remaining 49. Follow the three changes described above, writing the count left after each change on the same row. After the third change, divide the remaining count by 4 and record the line value.

Restore the active total to 49 only when starting a new line. Record the bottom line first and work upward until you have six rows, so you can check the counts after every change and the complete sequence of line values.

A computer simulation must follow the ideal probabilities stated above. Choosing a random split point does not necessarily produce that distribution; the way the split is sampled affects the probabilities.

Six-line example: Jie changes to Zhun

Read the following example from the bottom line upward, restarting at 49 for each line. It gives 7, 9, 8, 8, 7, 8. Only line 2 is moving. The intermediate counts let you check each subtraction as well as the resulting line type.

Dui (Lake) below Kan (Water) gives Jie (Limitation), hexagram 60. Reversing line 2 from yang to yin turns the lower trigram into Zhen (Thunder), producing Zhun (Difficulty at the Beginning), hexagram 3. The nuclear hexagram takes lines 2, 3, 4 below and 3, 4, 5 above, giving Zhen below Gen, or Yi (Nourishment), hexagram 27. Under Zhu Xi's rule for one moving line, the text of Jie's second line, Nine in the Second Place, is the focus within the whole figure.

Bring the result back to your question

Yarrow casting can produce no moving lines, one, or several; the Jie example is just one possible pattern. Check all six values, the primary hexagram, and every position valued 6 or 9 before examining the changed hexagram. No moving lines is a valid result, so there is no need to cast again to obtain movement.

Yarrow readings emphasize the classical text and the choice of focus according to the moving lines. Relate what you read to something concrete, such as time boundaries within a plan, and check the actual conditions before acting. The reading is a reference for reflection, not a prediction.

Kinh Dich Online currently casts with three coins; the Plum Blossom Body (Ti) / Function (Yong) method appears only as a supplementary cross-check in the reading.

Quick answers

Why begin with 50 stalks but count only 49?
The Great Expansion procedure sets one stalk aside unused. Each line begins with 49 active stalks; after three changes, divide those remaining by 4.
Can counting sticks replace yarrow stalks for practice?
You can use 50 counting sticks, set one aside, and follow the procedure with the remaining 49; record the count after each change and the six lines from bottom to top.
Does yarrow produce more moving lines than coins?
In the ideal model, both methods give a moving line with probability 1/4. They differ in the relative frequencies of moving yin and moving yang.

Hexagrams in this article

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