How upper and lower trigrams form one hexagram

One trigram on top of another

Every hexagram is one trigram placed on another: the lower one first, then the upper one, six lines in all. There are eight choices for each half, so the set is an 8 × 8 table, not a ready-made list. For another way of counting to sixty-four, see yin and yang lines.

A six-line figure built this way is called a doubled hexagram, and its building blocks are single trigrams (three-line figures). Lay the upper trigrams along one side and the lower trigrams along the other, and each crossing cell is one hexagram.

Open the full-size diagram

Lookup sketch: row = lower trigram, column = upper trigram. A combination table, not a sequence and not a table of outcomes.

Use the table by finding the row first, then the column. Hexagrams whose plain spelling would repeat are told apart by the Chinese in brackets: Qian (谦) is a hexagram, not the trigram Qian, and likewise Kun (困), Bi (比) and Bi (贲), Yi (益) and Yi (颐), Jian (蹇) and Jian (渐), Lü (履) and Lü (旅). The eight tinted cells lie on the diagonal; each has the same trigram above and below, and their names are written differently, as the fourth section shows.

Lower below, upper above: how positions are counted

The six lines are counted from the bottom: first, second, third, fourth, fifth and top. The first three form the lower trigram, also called the inner trigram; the last three form the upper trigram, also called the outer one. What each position means is the topic of line positions; here we only count.

The lower three lines of Zhun are yang, yin, yin, which is Zhen; the upper three are yin, yang, yin, which is Kan. Exchange them and you get Jie: yin, yang, yin below and yang, yin, yin above. Both use the same two trigrams, but their places differ, so they are not one hexagram. From trigrams to hexagrams in Meihua draws the same contrast with Tai and Pi, with more attention to casting.

The Commentary on the Images (象传) describes above and below in the same way: for Jiji it reads “water above fire: Jiji”. Water is the upper trigram Kan and fire is the lower trigram Li, and the upper one is named first.

Water above fire: Jiji.

From six lines to a name in three steps

There is no need to memorise sixty-four pictures. Split the figure into two trigrams, name each, then find the crossing cell.

Rows and columns follow the same trigram order, which is why every figure with identical halves sits on the diagonal. For the line shapes and images of the trigrams themselves, see the eight trigrams.

1. 1

   Write the six lines from the bottom

   Mark a yang line 1 and a yin line 0, starting with the lowest line, never from the top of the picture.

2. 2

   Split into halves of three

   Lines one to three are the lower trigram and four to six the upper; name each half from the reference chips.

3. 3

   Row for lower, column for upper

   Find the lower trigram’s row and the upper trigram’s column in the table; the crossing cell gives the name.

Two ways to write a hexagram name

One hexagram is commonly written in two forms. In the Zhou Yi text each figure has a single name such as Zhun, Jiji or Tai. Later tables, and Liuyao and Meihua material, often put the images of the two trigrams in front: Water over Thunder, Zhun (水雷屯), Water over Fire, Jiji (水火既济) or Earth over Heaven, Tai (地天泰).

Read “Water over Thunder, Zhun” as follows: water is the upper trigram Kan, thunder is the lower trigram Zhen, and Zhun is the name, which matches the 1 0 0 0 1 0 of the second section. The eight figures with the same trigram on both sides are known together as the eight pure hexagrams (八纯卦); the table below gives their names.

After the lookup: three easily confused things

A name found only tells you which hexagram this is. Three operations look alike and are easy to mix up.

For how each hexagram’s Judgment and line statements are read, see hexagram and line statements.