The I Ching (Yijing, the “Book of Changes”) is one of China's oldest classics. Originally a manual of divination, it was later expounded by Confucius and generations of scholars and came to head the Confucian canon. This tool reproduces its simplest casting method — the six-line coin method, also called the “copper-coin oracle” — together with the Judgments and line texts of all sixty-four hexagrams.
1. What is the six-line coin method?
The ancient method cast yarrow stalks by the “great expansion” procedure, which is elaborate; later ages simplified it to tossing three coins six times, hence the name “coin method”. An old coin carries an inscription on one side, called the “face” (zi); the other side is blank and is called the “back” (bei). By the ancient rule the back is yang and the face is yin: each toss of three coins counts backs and faces to fix one line's yin or yang and whether it is “moving” or “static”:
- Three backs (three yang) → old yang (number nine, a moving line, drawn as “○”)
- Two backs, one face → young yin (number eight, static)
- One back, two faces → young yang (number seven, static)
- Three faces (three yin) → old yin (number six, a moving line, drawn as “×”)
Tossing six times from the bottom up gives, in order, the first, second, third, fourth, fifth and top lines — one hexagram, the primary hexagram.
2. How a hexagram is built: eight trigrams and sixty-four hexagrams
Of the six lines, the lower three form the “lower trigram” and the upper three the “upper trigram”, each one of the eight primary trigrams:
- Qian ☰ (Heaven), Dui ☱ (Lake), Li ☲ (Fire), Zhen ☳ (Thunder)
- Xun ☴ (Wind), Kan ☵ (Water), Gen ☶ (Mountain), Kun ☷ (Earth)
Stacking an upper and a lower trigram yields the sixty-four hexagrams (numbered in the King Wen sequence). For every hexagram this tool gives the Judgment — the original I Ching verdict on the hexagram as a whole — and six line texts, a note on each line, plus a one-line plain-language gist to help you read them.
3. Primary hexagram, moving lines and changed hexagram: what “transformation” means
Among the six lines cast, old yang and old yin are the moving lines. By the principle that an extreme reverses, they transform: old yang becomes yin, old yin becomes yang. Change each moving line of the primary hexagram and you obtain another hexagram — the changed hexagram.
- Primary hexagram: the present state and shape of the matter.
- Moving lines: where the change lies; their texts are usually the heart of the reading.
- Changed hexagram: the tendency and outcome the matter is moving toward.
If all six lines are static (no moving line), there is no changed hexagram; judge by the Judgment of the primary hexagram alone.
4. How to read it
- Read the primary hexagram's Judgment first: grasp the overall character of the situation (fortune, misfortune, regret, difficulty).
- Then read the moving lines: if there are moving lines, go through their texts one by one; they usually offer concrete reminders.
- Then read the changed hexagram's Judgment: it shows where things are heading and can be set against the primary hexagram, beginning against end.
- For a static hexagram, the primary alone: with no moving line the matter changes little, and the primary hexagram's Judgment suffices.
Traditional readings also consult the “nuclear”, “opposite” and “reversed” hexagrams; this tool keeps it simple and shows only the main line — primary hexagram → moving lines → changed hexagram.
5. The right attitude
The I Ching says, “When at rest the gentleman observes its images and plays with its texts; when active he observes its changes and plays with its judgments.” The ancients used it to cultivate themselves, read situations and resolve doubts — not to court luck. Divination rests on sincerity and stillness: having cast, look inward and weigh reason and circumstance. Never let a hexagram replace your own judgment and action, and never use it for medical, legal or investment decisions.