Significance of Sun and Moon in the Yi Jing

Why does Stuart render the Yijing as the Book of Sun and Moon instead of using the standard translation, Book of Changes?

To answer that, we have to look carefully at what the character Yi (易) actually means and how Stuart interprets it in his introduction.

This is not a poetic flourish. It is not metaphorical decoration. Stuart is pointing to something structural and foundational within the text itself.

The Character Yi: Sun and Moon Embedded in the Ideogram

Stuart explains that the title comes directly from the structure of the Chinese character Yi.

He writes:

“The use of sun and moon in the title comes from the two radicals that comprise the ideogram Yi.

Ra is the upper radical and that translates as the Sun, and Wu, the bottom radical, is an older variant of Yue, the moon. Therefore Yi is an ideogram denoting the Sun and Moon—or better said, the constant interchange of movements of the Sun and Moon.”

The word Yi does not simply mean “change” in an abstract sense. It refers to a specific kind of change—the patterned, rhythmic interchange modeled on the movements of the sun and moon.

A Specific Kind of Change

The change described in the Yi is not random or chaotic. It is rhythmic alternation:

• Brightness and darkness

• Activity and receptivity

• Appearing and withdrawing

These patterns mirror the daily and monthly movements of the sun and moon.

So when Stuart uses “Sun and Moon,” he is naming the structural cosmology embedded in the character itself. The Yi is describing patterned illumination moving through time.

The Meaning of Jing

Stuart is equally precise about the second half of the title: Jing (經). He explains that Jing does not simply mean “book.”

It means:

• A classic

• A foundational text

• Something that gives structure and meaning over time

A Jing is not something you read once. It is something you return to repeatedly as a reference point.

Taken together, Yijing—Book of Sun and Moon—is not a reinterpretation. It names what the text actually is:

A foundational classic that lays out how change works according to the patterned movement of Sun and Moon.

Sun and Moon as Yin and Yang

Stuart reinforces this understanding by connecting Sun and Moon to yin and yang.

Importantly, yin and yang here are not philosophical abstractions or moral opposites. They are observable natural processes.

He discusses the image of the chameleon in relation to Yi:

“The chameleon was symbolic of how the sun and moon likewise changes in brightness and darkness.”

In this context:

• Yin and yang are patterns of illumination and obscuration.

• They are rooted in natural cycles.

• They describe how light appears, fades, and returns.

Built into the Structure of the Trigrams and Hexagrams

Sun and Moon are not only symbolic—they are structurally embedded in the Yi.

Stuart explains:

• The trigram for Heaven is associated with and revealed by the trigram of Fire (the Sun).

• The trigram for Earth is associated with and revealed by the trigram for Water (the Moon).

Sun and Moon operate simultaneously on multiple levels:

1. Cosmically

• Heaven and Earth

2. Terrestrially / Humanly

• Fire and Water

3. Structurally

• Odd-numbered hexagrams correspond largely to Sun (yang).

• Even-numbered hexagrams correspond largely to Moon (yin).

4. Logically

The hexagrams are paired.

If you take an odd-numbered hexagram (a Sun image) and reverse it, you often get the following even-numbered hexagram (a Moon image). The second reflects the first.

For example:

• Hexagram 3

• Hexagram 4 is its reflected pair

This pairing is one way of moving through the book—by studying the Sun/Moon reflections.

Reflection, Not Opposition

Stuart emphasizes that this pairing establishes reflection, not opposition.

He says:

“The moon can only be viewed when it is reflecting the light of the Sun. So too, Yin images arise in response to Yang images.”

The pattern appears through:

• Alternation

• Response

• Reflection

Not randomness. Not dualistic conflict. The Moon does not fight the Sun. It reflects it.

Classical Foundation: The Ten Wings

Stuart further anchors this interpretation by quoting the Ten Wings:

“The Sun departs and then the moon arrives. The moon departs and then the Sun arrives. The Sun and Moon each take the other’s place and so their illumination is created.”

This shows that the Sun–Moon logic is not Stuart’s invention. It is classical and foundational.

The Mathematical and Logical Structure

Finally, Stuart points out that the Book of Sun and Moon is mathematical and logical in nature.

He writes:

“Instead of using the values of zeros and ones… the Book of Sun and Moon uses yin and yang to accomplish the same thing. It makes an image.”

In this sense:

• Yin and yang function like binary code.

• Sun and Moon form the operating structure.

• The hexagrams are generated through patterned alternation.

Sun and Moon are the binary engine of the Yi.

They govern:

• How images are formed

• How they transform

• How meaning unfolds through time

Conclusion: What the Title Really Means

In Stuart’s introduction, “Sun and Moon” names the engine of the Yi. The Book of Sun and Moon is not about abstract change. 

It is about:

• Rhythmic alternation

• Reflection

• Response

• Illumination moving through time

Change is not chaos. It is patterned light and darkness taking each other’s place. That is why Stuart does not call it the Book of Changes. He calls it the Book of Sun and Moon.