I Ching · Structure

The Eight Trigrams 八卦

The eight trigrams (八卦 Bā Guà) are the alphabet of the I Ching. Each is a stack of three lines, solid (Yang) or broken (Yin). Three binary positions give exactly eight combinations — and those eight, paired two by two, generate the 64 hexagrams.

How they are formed

The trigram is read from the bottom up: the first line is the base, the third the top. Solid line writes Yang, broken line writes Yin. There is nothing arbitrary in the count: with three positions and two possible values, eight is all there is.

Each trigram carries a natural image, a family position and a movement. The image is not decoration — it is the shortest way to remember what that configuration does.

The eight

• Qian 乾 — Heaven. Three solid lines. Pure initiative, the force that begins.
• Dui 兌 — Lake. Openness at the top: pleasure, exchange, what receives.
• Li 離 — Fire. Empty at the centre: clarity that depends on what it burns; adherence.
• Zhen 震 — Thunder. Movement from below: shock, the impulse that starts.
• Xun 巽 — Wind. Penetration that is gentle and persistent, gradual influence.
• Kan 坎 — Water. Full at the centre, open at the edges: danger, depth, what flows through.
• Gen 艮 — Mountain. Stillness at the top: the limit, the pause, what holds.
• Kun 坤 — Earth. Three broken lines. Pure receptivity, what sustains and gives form.

From trigram to hexagram

A hexagram is two trigrams stacked: the lower one describes the inner situation, what belongs to the querent; the upper one, the outer situation, what comes from outside. Eight times eight gives the 64 — and reading the pair is the first thing to do with any hexagram.

The cosmology page carries a selector where each trigram is built line by line, showing its name, image and family — useful for fixing the set in memory.

Further

• The 64 hexagrams — each with its two trigrams and classical meaning.
• Yin and Yang — the pair the lines write.
• Consult the I Ching online — three free themes a day.