Nine Paths of the Moon: Which Yellow Path Does the Old Text Mean?
A lunar text moves from directions to seasonal mansion classifications. Spring wood and summer fire show why a shared name does not establish a shared meaning, or turn an old category into a fact about a person.
When opening an old book and seeing the four characters "the Moon travels the Nine Paths" (月行九道), it is easy to assume that the ancients drew nine orbital tracks for the Moon. As you read further, you discover that the "Yellow Path" (huangdao) is at one moment the central path in the sky, and at another becomes a designation assigned in accordance with the four seasons and the lunar-mansion groups. The same name performs different tasks across different passages; this is precisely what requires the closest attention when reading this kind of text.
Look first at the formulation in "Taiyin huangdao lun" (Treatise on the Moon and the Yellow Path) in Zhang Guo Xingzong. It states that the Moon has nine courses, taking the Yellow Path as the master of the warp and weft, and then divides into two Azure Paths emerging to the east of the Yellow Path, two Red Paths emerging to the south of the Yellow Path, two White Paths emerging to the west of the Yellow Path, and two Black Paths emerging to the north of the Yellow Path, with the four seasons shifting in accordance with the Yellow Path. Here, the Yellow Path resembles a baseline, with the other paths extending out from its four cardinal directions. It then recites the starting directions for spring, summer, autumn, and winter respectively—spring begins in the east, summer in the south, autumn in the west, and winter in the north—and explains that "the Lunar Body (Taiyin) is the master of the bodily self (shen)," linking the Moon to the "bodily self" used in assessing fate. Reading to this point, one can already sense that this passage is not merely describing how the Moon travels; it organizes celestial vocabulary into a framework that can be employed for discourse.
Coming to "Taiyin jiuxing li" (Examples of the Moon's Nine Courses), the very same "Yellow Path" changes its usage. At the outset it still states, "the Sun travels the Yellow Path and the Moon travels the Nine Paths; the Yellow Path is the central path," seemingly continuing the celestial picture from the preceding text. But very quickly the writing shifts, offering a set of rules for assigning the names of the paths according to the lunar mansions traversed by the Moon: in the spring season of birth, traversing the Wood mansions of Jiao, Dou, Kui, and Jing is called traveling the Yellow Path; traversing the Fire mansions of Wei, Shi, Zui, and Yi is called traveling the Azure Path; traversing the Water mansions of Ji, Bi, Shen, and Zhen is called traveling the White Path; traversing the Metal mansions of Kang, Niu, Lou, and Gui is called traveling the Red Path; traversing the Earth mansions of Di, Nü, Wei, and Liu is called traveling the Black Path. The same passage uses generation and overcoming relationships to explain each path, and points out the role of seasonal timing with the phrase "its assessment takes whatever is in season as the Yellow Path." Further along, that which is prosperous (wang) is the Yellow Path, that which is assisted (xiang) is the Azure Path, that which is resting (xiu) is the White Path, that which is trapped (qiu) is the Red Path, and that which is dead (si) is the Black Path.
This makes it very clear: in this passage, the criterion for determining the "Yellow Path" is not that line in the sky, but conditions such as being "in season" or "prosperous." The name has not changed, but what it designates is already the coordinated relationship among the seasonal orders, the Five Phases, and the lunar-mansion groups.
"Sishi taiyin suo jing zhi du" (The Degrees Traversed by the Moon across the Four Seasons) articulates this coordination in even finer detail. In accordance with the four seasonal nodes—the Start of Spring, Start of Summer, Start of Autumn, and Start of Winter—it lists in sequence four mansions each under Wood, Fire, Water, Metal, and Earth, noting that Jiao, Dou, Kui, and Jing are the four Wood mansions; Wei, Shi, Zui, and Yi are the four Fire mansions; Kang, Niu, Lou, and Gui are the four Metal mansions; Ji, Bi, Shen, and Zhen are the four Water mansions; Di, Nü, Wei, and Liu are the four Earth mansions; Fang, Xu, Mao, and Xing are the four Sun mansions; and Xin, Wei, Bi, and Zhang are the four Moon mansions. Reading the entire passage feels like looking at an allocation chart of lunar mansions rotating with the seasonal orders. For instance, in the spring season, the Wood mansions are ranked first and called the Yellow Path; the Fire mansions follow and are called the Azure Path; the Water mansions are the White Path; the Metal mansions are the Red Path; and the Earth mansions are the Black Path. In the summer season, the Fire mansions are ranked first and become the Yellow Path, the Earth mansions are the Azure Path, the Wood mansions are the White Path, the Water mansions are the Red Path, and the Metal mansions are the Black Path. Once the order changes, the path names change along with it. Here the "Yellow Path" is more like a position label—whichever slot is in season is assigned this name.
For the same term, several interconnected expressions can be discerned across these consecutive passages: first, the central path baseline on the celestial sphere; second, the in-season slot when seasonal orders and lunar mansions are coordinated; and third, the status determined by the set of conditions of prosperous, assisted, resting, trapped, and dead. They are written within the same body of text, yet each relies on a different ground. We need not rush to claim that they are two mutually exclusive entities, nor have we yet sorted out the complete theoretical relationship among these expressions. A sounder way to read them is: first acknowledge that this body of text actually draws upon multiple vocabularies, and then return each instance of "Yellow Path" to the sentence where it resides to see what question it is ultimately answering.
A simple comparison can be made here. Suppose someone is born in the spring season, and the Moon traverses the Wood mansions of Jiao, Dou, Kui, and Jing; according to the rules of "Taiyin jiuxing li," this is called the Moon traveling the Yellow Path. If the time is summer, and the Moon traverses the Fire mansions of Wei, Shi, Zui, and Yi, this is likewise called the Moon traveling the Yellow Path. Both instances are the "Yellow Path," but one relies on Wood mansions being in season in spring, while the other relies on Fire mansions being in season in summer. The name is identical, but the underlying conditions are not. If one seizes solely upon the two characters "Yellow Path" and takes them as some personal birth coordinate or personality fact, one has mistaken a classification label used in the book for a judgment about a specific person.
The passage "Taiyin jiudao duan" (Judgments on the Moon's Nine Paths) indeed carries evaluations of morality, nobility, and baseness. It says that a person of the Yellow Path is intelligent, clear, harmonious, and pure; an Azure Path person is mostly upright and principled; a Red Path person possesses much tactical calculation, relies on circumstance, and acts boldly; while a Black Path person is foolish yet opinionated, base yet prone to arbitrary action. These sentences cannot be prettified into a set of neutral astronomical descriptions, nor should they be adopted as today's personality typology. They are judgments given by an old text within a specific discursive framework, possessing their own context and limits. In reading, we can treat them as material showing "how the ancients used path names to organize descriptions of people," rather than evidence that "path names can truly appraise personality."
Therefore, when reading "the Moon travels the Nine Paths" in old books, the first step is not to memorize the names of the nine paths, but to ask: what is this term doing in this sentence? Is it speaking of celestial directions, or the coordination between seasonal orders and lunar mansions, or the conditions of prosperous, assisted, resting, and trapped? The second step is to see what conditions it subsequently uses for classification. Having the same name does not equal having the same referent; elegant ancient phrasing does not mean the ancients have already settled conclusions for today's readers. This set of texts weaves together the central path, orientations, four seasons, Five Phases, lunar mansions, and auspicious or inauspicious evaluations. What we can do is identify which grounds it actually employed, rather than invent for it a complete system that it never wrote down.
If you encounter different accounts of the Nine Paths in other old books, or discover layers within this set of passages that this article has not fully clarified, you are welcome to provide counterexamples or corrections; we are willing to amend our account accordingly.
This article is based on fixed digital transcriptions of "Taiyin huangdao lun," "Taiyin jiuxing li," "Sishi taiyin suo jing zhi du," and "Taiyin jiudao duan," and has not yet been collated page by page against a facsimile edition.