The Eight Trigrams and the Two Halves

Three lines give eight combinations

In the first lesson we stacked yin and yang six layers deep. Step back and stack only three.

Each layer can be yin or yang, so three layers give 2×2×2 = 8 arrangements — no more, no fewer. Each of the eight has a name, and together they are called the eight trigrams.

The trigrams are not a separate system. They are just a way of treating three lines as one unit. Six lines are hard to hold in mind at once; split in half, you only need to remember eight names.

What the eight trigrams look like

As always, read from the bottom up. "Yang yang yang" means the bottom line is yang, the middle is yang, and the top is yang too.

Qian ☰ yang yang yang, traditionally paired with heaven. Dui ☱ yang yang yin, paired with lake. Li ☲ yang yin yang, paired with fire. Zhen ☳ yang yin yin, paired with thunder. Xun ☴ yin yang yang, paired with wind. Kan ☵ yin yang yin, paired with water. Gen ☶ yin yin yang, paired with mountain. Kun ☷ yin yin yin, paired with earth.

Heaven, lake, fire and thunder are traditional images attached to the trigrams as memory aids and sources of association. They are not what the symbols mean by definition. The definition is only this: the arrangement of yin and yang across three lines.

Split a hexagram in half yourself

A six-line hexagram can be read as two trigrams stacked: the bottom three lines (first, second, third) are the lower trigram, and the top three (fourth, fifth, sixth) are the upper one. Change only the bottom three and only the lower trigram changes; the upper one is untouched, and the same holds the other way round. The two halves are independent — that is what “upper and lower trigram” means.

Which three lines are the lower half

The split never varies from hexagram to hexagram. Lines one, two and three together are the lower trigram, also called the inner trigram. Lines four, five and six are the upper trigram, also called the outer trigram.

Note that the direction is still bottom-up. Within the lower trigram, the bottom stroke is that trigram's own first line. Within the upper trigram, line four is that trigram's own first line.

The next lesson uses this split: eight possible lower trigrams times eight possible upper trigrams produce exactly sixty-four hexagrams.

Try it yourself

This lesson has a hands-on exercise. It is built into the Traditional Chinese lesson page, where you can try it straight away: open the interactive exercise.

Remembering the eight trigram names with a short rhyme

There is a traditional set of mnemonics that describe each of the eight trigrams by its shape: Qián is “three unbroken” ☰, Kūn is “six broken” ☷, Zhèn is “an upward-facing bowl” ☳, Gèn is “an overturned bowl” ☶, Lí is “hollow in the middle” ☲, Kǎn is “full in the middle” ☵, Duì is “broken at the top” ☱, Xùn is “broken at the bottom” ☴. Each phrase says what the symbol looks like, not what it means.

Qián has all three lines unbroken; Kūn has all three broken, so there are six gaps in total. In Zhèn only the bottom line is yang, like a basin opening upward; in Gèn only the top line is yang, like a bowl turned upside down. Lí has yang above and below with yin in the middle, so the middle is empty; Kǎn has yin above and below with yang in the middle, so the middle is solid. In Duì the top line is broken; in Xùn the bottom line is broken.

The eight trigrams also have familiar correspondences: Qián with heaven, Kūn with earth, Zhèn with thunder, Gèn with mountain, Lí with fire, Kǎn with water, Duì with lake, Xùn with wind. These are associations that help you remember each one’s character; you do not need to memorise them to use this app.

How the lower and upper trigram are usually read

Once the six lines are split in two, the bottom three are the lower trigram, also called the inner trigram, and the top three are the upper trigram, also called the outer trigram. The inner and outer names already hint at the reading: the lower trigram is often taken as the part closer to you, the inside, the beginning, and the upper trigram as the part that is more outside, the other party, what follows.

Note that this is a reading habit, not a mechanical rule. The same hexagram can have its two halves stand for different things depending on what is being asked. On each of the 64 hexagram pages this app states what the two halves of that hexagram are and gives the reason for its interpretation, so you can judge for yourself whether to accept it.

The cut is always in the same place: lines one to three are always the lower trigram and lines four to six always the upper trigram, regardless of which line is a moving line. This has nothing to do with moving lines, which lesson 4 covers.

Swap the top and bottom and you get a different hexagram

When two trigrams are stacked, which one is on top matters. With Qián ☰ below and Kūn ☷ above you get hexagram 11, Tài; swap the two halves, with Kūn ☷ below and Qián ☰ above, and you get hexagram 12, Pǐ. The symbols use the same two trigrams, but the arrangement of the six lines is different, so they are different hexagrams, with different names and different judgments.

This also explains why there are only eight trigrams but sixty-four hexagrams: 8×8 combinations count “which one is on top and which on the bottom” as two different results. Only the eight cases where the upper and lower trigram are identical, such as Qián over Qián or Kūn over Kūn, stay the same when swapped.

Quick Quiz