Primary · 本卦 ben gua
Waiting for six lines (0 of 6 placed).
Resources / Cosmological instruments
Yijing Consultation Caster
Build a hexagram line by line, from the bottom up, with three coins, the odds of the yarrow-stalk procedure, or by hand from a casting you made yourself. The primary, relating and nuclear hexagrams update as each line lands.
The instrument does the arithmetic of the casting and names its figures. It does not quote or interpret the classical texts, and it labels where traditions disagree.
Method
Cast six lines
Three coins per line, one face counted as 3 and the other as 2 (sources differ on which face is which). The sum is 6, 7, 8 or 9.
Cast with coins or yarrow, or switch to manual to transcribe a physical casting.
Lines · read from the bottom up
The casting
0 of 6
- 1Basenext
- 22ndLine 2 not yet cast
- 33rdLine 3 not yet cast
- 44thLine 4 not yet cast
- 55thLine 5 not yet cast
- 6TopLine 6 not yet cast
Each placed line is a button: activate it to cycle 6 → 7 → 8 → 9 → 6. A cross marks 6 (old yin) and a circle marks 9 (old yang).
The lower trigram forms after three lines; the hexagram after six.
Odds for each line
- 6 old yin
- 1/8
- 7 young yang
- 3/8
- 8 young yin
- 3/8
- 9 old yang
- 1/8
Derived figures · recomputed live
Primary, relating and nuclear
Relating · 之卦 zhi gua
Appears once six lines are placed and at least one of them is moving (6 or 9).
Nuclear · 互卦 hu gua
Appears once six lines are placed: lines 2–4 of the primary become the lower trigram and lines 3–5 the upper.
Activate a relating or nuclear figure to make it the primary, as six unmoving lines. English names follow Wilhelm–Baynes; notes are Aetherica study glosses, not translations.
One traditional rule · Zhu Xi, Yixue qimeng (as usually summarised)
Which texts to read
Complete the casting to see which judgment or line statements this scheme points to.
This is one school's rule, not a universal one. Many readers consult every moving line and both judgments, and others weigh the texts differently. The instrument names texts but does not quote or interpret them.
Probability per line
Coins and yarrow compared
| Line | Coins | Yarrow |
|---|---|---|
| 6 Old yin | 1/8 | 1/16 |
| 7 Young yang | 3/8 | 5/16 |
| 8 Young yin | 3/8 | 7/16 |
| 9 Old yang | 1/8 | 3/16 |
| Line moves | 1/4 | 1/4 |
| Yang in primary | 1/2 | 1/2 |
| Yang in relating | 1/2 | 3/8 |
| No line moves (all six) | 17.8% | 17.8% |
Both methods move a line one time in four and give the primary hexagram even odds of yang. They part company over which lines move: yarrow makes old yang three times as likely as old yin, so its relating hexagrams lean towards yin.
The tradition
The Yijing, or Book of Changes, is built from sixty-four hexagrams: stacks of six lines, each solid (yang) or broken (yin), read from the bottom up. Its core text, the Zhouyi, gives every hexagram a judgment and six line statements. It is usually dated to the Western Zhou, and the commentaries known as the Ten Wings gathered around it over the following centuries.
To consult it, six lines are produced by a chance procedure. The Great Commentary (Xici) preserves a terse passage on the 'great expansion' number from which the yarrow-stalk procedure is reconstructed; the step-by-step form most people perform follows Zhu Xi's reconstruction. The three-coin method is later and quicker, and its traditional attributions cannot be securely dated. Either way each line comes out as 6, 7, 8 or 9: 6 and 9 are 'old' lines, taken to be moving, while 7 and 8 are 'young' and stay as they are.
Reading the instrument
- Lines build from the bottom up. A cross marks 6 (old yin) and a circle marks 9 (old yang), the traditional signs for moving lines.
- Every placed line is a button that cycles 6 → 7 → 8 → 9, so a casting done with real coins or stalks can be transcribed exactly. Manual mode adds lines by value with no random draw at all.
- Primary hexagram (ben gua 本卦): the lines as cast. Relating hexagram (zhi gua 之卦, also called the changed or resulting hexagram): every moving line turns into its opposite. When no line moves there is no relating hexagram. Nuclear hexagram (hu gua 互卦): lines 2–4 of the primary form its lower trigram and lines 3–5 its upper.
- The odds depend on the method. Both give each line a one-in-four chance of moving, but yarrow stalks make old yang three times as likely as old yin, which tilts the relating hexagram towards yin. Coins treat old yin and old yang alike.
- English names follow the Wilhelm–Baynes translation. The short notes are Aetherica study glosses, not translations of the judgment texts.
Where it descends from
- Zhouyi (The Changes of Zhou)
- The core text: hexagram figures, judgments and line statements, in the King Wen order used here.
- Xici zhuan (The Great Commentary)
- One of the Ten Wings. Its 'great expansion' passage is the textual basis for the yarrow-stalk procedure.
- Shuo Gua (Discussion of the Trigrams)
- The received source for the trigram images used to name each hexagram's upper and lower halves.
- Yixue qimeng (Introduction to the Study of the Changes)
- Zhu Xi's manual, behind the usual reconstruction of the yarrow procedure and the rule for which moving-line texts to read.
- I Ching, or Book of Changes (Richard Wilhelm, tr. Cary F. Baynes)
- The English naming convention used for the sixty-four hexagrams.
What this does not claim
This instrument casts and derives hexagrams. It does not quote the classical texts, interpret a reading, or predict anything. Random lines come from your browser's cryptographic generator, weighted by the probability tables shown. Whether a chance procedure carries meaning is a question of practice and belief that arithmetic cannot settle. Traditions disagree about which moving-line texts to read and about how much weight the nuclear figure deserves: Han image-and-number commentators used interlocking trigrams, and Wang Bi rejected the practice. The reading rule shown here is one school's.
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