How to Read Changing Lines in the I Ching
When three coins are tossed, numerical sums of 6 and 9 produce moving lines that transform yin into yang or yang into yin. Here is how moving lines arise and how they have traditionally been read.
The Four Numerical Sums of Three Coins
Each coin has two faces: an inscribed character face valued at 2 (even, yin) and a plain face valued at 3 (odd, yang). Tossing three coins yields 2³ = 8 equally probable permutations:
| Sum | Face values | Traditional name | State | Probability |
|---|---|---|---|---|
| 6 | 2 + 2 + 2 (3 inscribed) | Old Yin (老陰) | Moving line (transforms into Yang —) | 1 in 8 (12.5%) |
| 7 | 3 + 2 + 2 (1 plain, 2 inscribed) | Young Yang (少陽) | Static line (remains Yang —) | 3 in 8 (37.5%) |
| 8 | 3 + 3 + 2 (2 plain, 1 inscribed) | Young Yin (少陰) | Static line (remains Yin -- --) | 3 in 8 (37.5%) |
| 9 | 3 + 3 + 3 (3 plain) | Old Yang (老陽) | Moving line (transforms into Yin -- --) | 1 in 8 (12.5%) |
Static lines (7 and 8, 37.5% each) come up three times as often as moving lines (6 and 9, 12.5% each). A moving line has reached its extreme and is about to turn into its opposite.
Worked Example: Toss Sequence 7 · 9 · 8 · 7 · 7 · 8
Suppose the six tosses from bottom to top yield 7, 9, 8, 7, 7, 8. Only line 2 is a 9 (Old Yang, moving):
- Line 1 (bottom)
- 7 (Young Yang) → Solid line (—)
- Line 2
- 9 (Old Yang) → Moving Yang (—) turning to Yin (-- --)
- Line 3
- 8 (Young Yin) → Broken line (-- --)
- Line 4
- 7 (Young Yang) → Solid line (—)
- Line 5
- 7 (Young Yang) → Solid line (—)
- Line 6 (top)
- 8 (Young Yin) → Broken line (-- --)
- Primary Hexagram
- Hexagram 58 (兌, Duì · The Joyous)
- Relating Hexagram
- Hexagram 17 (隨, Suí · Following)
Traditional Reading Rules (Zhu Xi's Interpretation Method)
In his treatise Yixue Qimeng (易學啟蒙), Song-dynasty scholar Zhu Xi (朱熹) formulated seven clear guidelines for reading hexagrams based on how many moving lines occur:
| Moving lines | Focus of reading | Traditional rule |
|---|---|---|
| 0 | Primary hexagram judgment | No lines change; contemplate the primary hexagram judgment (卦辭). |
| 1 | Single moving line text | Read the line statement of the moving line in the primary hexagram (本卦動爻爻辭). |
| 2 | Both moving lines | Read both moving lines in the primary hexagram, with the upper moving line as primary focus. |
| 3 | Primary & relating judgments | Read both judgments: the primary hexagram for the present, relating hexagram for the outcome. |
| 4 | Two static lines in relating | Read the two non-moving lines of the relating hexagram, with the lower static line as primary focus. |
| 5 | Single static line in relating | Read the sole remaining static line of the relating hexagram. |
| 6 | Special lines or relating | For Qián use Yong Jiu (用九); for Kūn use Yong Liu (用六); for all other hexagrams read the relating hexagram judgment. |
The Time Method (Plum Blossom Numerology)
Unlike the coin method which can produce between zero and six moving lines, the Plum Blossom (梅花易數) time method calculates exactly one moving line deterministically via the formula (T - 1) mod 6 + 1. It therefore always leads directly to rule #2 (one moving line).