Zi Ping Zhen Quan — On the Ten Heavenly Stems and Twelve Earthly Branches: Original Text, Translation & Interpretation

Between Heaven and Earth there is one qi (vital breath). There is movement and stillness, and thus yin and yang; there are the young and the old, and thus the Four Images. The old are the points at which movement and stillness reach their utmost: these are Greater Yang and Greater Yin. The young are the beginnings of movement and stillness: these are Lesser Yin and Lesser Yang. With these Four Images, the Five Phases (wuxing, also called the Five Elements) are contained within them. Water is Greater Yin; Fire is Greater Yang; Wood is Lesser Yang; Metal is Lesser Yin. Earth is formed from the qi in which yin and yang, the old and the young, and Wood, Fire, Metal, and Water intermingle.

“Old and young” here refer to stages of movement and stillness, not to a person’s age. “Greater Yang” and “Greater Yin,” together with Lesser Yang and Lesser Yin, name four states of yin and yang; they do not refer to celestial bodies. The text begins with the One Qi, distinguishes it by movement and stillness and by their beginnings and culminations, and then places Wood, Fire, Metal, and Water within the Four Images. Earth is described separately as formed from the intermingling qi, rather than simply being assigned as a fifth image.

Xu Lewu’s commentary explains Wood, Fire, Metal, and Water as the qi of the four seasons—spring, summer, autumn, and winter—and describes Earth as bearing the other four. This adds a seasonal way of reading the passage: Wood corresponds to spring, Fire to summer, Metal to autumn, and Water to winter. The passage itself states the correspondence between the Four Images and Five Phases; the seasonal reading and the account of Earth as bearer come from Xu’s commentary. The two layers should be kept distinct.

If the Five Phases are already present, why are there also the Ten Heavenly Stems and Twelve Earthly Branches? Yin and yang give rise to the Five Phases, and within each phase there is also yin and yang. Take Wood: Jia (甲) and Yi (乙) are its yang and yin. Jia is the qi of Yi; Yi is the substance of Jia. In Heaven, that which is life-generating qi and flows through the myriad things is Jia; on Earth, the myriad things that receive this life-generating qi are Yi. To distinguish them further: the spreading of life-generating qi is Jia within Jia, while its congealing is Yi within Jia; what enables the myriad trees to have branches and leaves is Jia within Yi, while the branches and leaves of the myriad trees themselves are Yi within Yi. In the Jia aspect, the qi of Yi is already complete; in the Yi aspect, the substance of Jia has become firm. With Jia and Yi, the yin and yang of Wood are complete.

The text first divides Jia and Yi into qi and substance, then further distinguishes yin and yang within each of those aspects. “Jia within Jia” and “Yi within Jia” are not two additional Heavenly Stems: within the aspect of life-generating qi, they distinguish its spreading from its congealing. “Jia within Yi” and “Yi within Yi” distinguish, within the aspect of substance, what enables branches and leaves to arise from the branches and leaves that have actually formed. To follow these four expressions, first identify which level is under discussion; the distinctions cannot be flattened into the labels “Jia is yang” and “Yi is yin.”

“Jia is the qi of Yi; Yi is the substance of Jia” emphasizes that the two aspects are connected, rather than making them two unrelated kinds of Wood. The final sentence likewise says that the aspect of Jia already contains Yi’s qi, while the aspect of Yi makes Jia’s substance firm. This continues the explanation of their mutual inclusion. The passage does not use this to state a rule of production, restraint, combination, transformation, or favorability when the two Stems meet in a chart.

Xu’s commentary goes on to explain the Heavenly Stems as the qi flowing through the Five Phases and the Earthly Branches as the sequence through which the four seasons flow; later it discusses Jia and Yi together as qi flowing in Heaven. That interpretation concerns the overall relationship between Stems and Branches. The text’s contrast between qi and substance here instead differentiates Wood and Jia-Yi internally. These explanations have different scopes: the former should not be used to rewrite the latter as “Yi represents only physical trees,” nor should the branch-and-leaf analogy be treated as a fixed method for reading chart symbols.

Why are Yin (寅) and Mao (卯) also present? They set Yin and Mao alongside Jia and Yi to speak of yin and yang in relation to Heaven and Earth. If yin and yang are distinguished between Jia and Yi, Jia is yang and Yi is yin: these are the yin and yang of Wood moving in Heaven. If they are distinguished between Yin and Mao, Yin is yang and Mao is yin: these are the yin and yang of Wood abiding on Earth. If Jia, Yi, Yin, and Mao are grouped together and divided into yin and yang, Jia and Yi are yang, while Yin and Mao are yin: Wood takes form as an image in Heaven and as a shape on Earth.

The passage makes three divisions, each with a different basis of comparison: Jia against Yi, Yin against Mao, and the group Jia-Yi against the group Yin-Mao. Yi is yin within the Stems Jia and Yi, but the two Stems together are yang in relation to Yin and Mao. Yin is yang within the Branches Yin and Mao, but the two Branches together are yin in relation to Jia and Yi. This does not reclassify Yi as a yang Stem or Yin as a yin Branch; it changes the level of comparison.

Xu’s commentary explains the distinction between Heaven and Earth by saying that “Jia and Yi are the qi that flows” and “Yin and Mao are the sequence of the seasons.” Read in that light, the Heavenly Stems and Earthly Branches each have their own inner yin-yang division, and they can also stand in contrast as two groups—qi and seasonal sequence. “Taking form as an image in Heaven and as a shape on Earth” belongs to the text’s language of Heaven, Earth, qi, and substance. It should not be reduced to saying that Stems have no form or Branches have no qi: the next passage still speaks of Jia and Yi acting upon Yin and Mao, and Yin and Mao receiving Jia and Yi.

Jia and Yi move in Heaven, while Yin and Mao receive them; Yin and Mao abide on Earth, while Jia and Yi act upon them. Thus Jia and Yi are like officials, and Yin and Mao like the territories under their administration. Jia’s Lu (禄) position is in Yin, and Yi’s Lu position is in Mao, just as a prefectural official is stationed in his prefecture and a county official in his county, each overseeing the command of one month.

The analogy of officials and territories explains how the Stems’ activity corresponds to the seasonal order received by the Branches. The text gives a specific correspondence: Jia’s Lu position is in Yin, and Yi’s Lu position is in Mao. Here “Lu position” denotes a relationship between a Stem and a Branch; it does not mean that a chart containing Yin or Mao necessarily grants a salary or an official post.

Following the official analogy, Xu’s commentary says that only when a Stem is rooted in the month command (yue-ling) and receives the qi that is in season can it be considered timely and well placed. It also says Jia and Yi can both take Yin and Mao as roots, and mentions Hai (亥), Wei (未), and Chen (辰) as well. This distinguishes the “Lu position” from the broader idea of a root: the text’s listed Lu positions, Jia-Yin and Yi-Mao, do not exhaust every Branch with which Jia and Yi may be associated. Xu’s explanation of rooting is supplementary; its broader set of roots should not be renamed the Lu positions listed in the text.

“Each overseeing the command of one month” also cannot by itself establish that the Stem of the Yin month must be Jia or that of the Mao month must be Yi. The next passage rejects precisely this fixed pairing. The analogy of officials and territories must be read together with the account of the Stems’ rotation.

Jia and Yi are in Heaven, and so they move rather than remain fixed. In a month established on Yin, must the Stem necessarily be Jia? In a month established on Mao, must it necessarily be Yi? Yin and Mao are on Earth, and so they stay in place rather than shift. The Stem paired with the Yin month may change in succession, but the month-Branch remains Yin; the Stem paired with the Mao month may change in succession, but the month-Branch remains Mao.

“Established on Yin” and “established on Mao” refer to the Branches of the months; they do not refer to the Day Stem, nor do they require the month’s Stem to form Jia-Yin or Yi-Mao. The preceding passage gives the Lu positions of Jia and Yi, and this passage immediately cautions that those correspondences do not replace the actual rotation of Stems through the months.

Xu’s commentary uses the first month of a Jia (甲) or Ji (己) year, which is Bing (丙)-Yin (寅), to illustrate that the Heavenly Stems move rather than remain fixed; it then identifies the first and second months with Yin and Mao. In this example, the Yin month is paired with Bing, which is enough to show that “established on Yin” does not mean “necessarily Jia.” This is an example supplied by the commentary. The passage itself says only that the month-Branch has a fixed sequence while the paired month-Stem changes; it does not give the complete rules for deriving month-Stems.

“Stay in place rather than shift” is relative to the changing Stem paired with a month. It does not mean that the year stays in Yin or Mao, nor that the twelve Branches have no progression. The sequence of month-Branches and the Stem paired with each month must be kept distinct; otherwise the seasonal order and the Stem-Branch combinations are conflated.

In terms of qi, Jia is more flourishing than Yi; in terms of substance, Yi is firmer than Jia. Yet common books make the mistaken claim that Jia is a great forest, flourishing and therefore fit to be cut down, while Yi is a small seedling, frail and therefore not to be harmed. This shows a failure to understand the principle of yin and yang. Wood may be used to infer the same for the other phases. Earth alone is the qi formed from the intermingling of Wood, Fire, Metal, and Water, and so has its periods of flourishing within the four seasons; the principles of yin-yang, qi, and substance apply to it as well. Anyone wishing to study fate must first understand the Stems and Branches; only then can they enter the subject.

The phrases “in terms of qi, Jia is more flourishing than Yi” and “in terms of substance, Yi is firmer than Jia” compare them on different levels. They do not say that Jia is stronger than Yi in every chart, nor that Yi is necessarily a harder kind of tree than Jia. In light of the preceding discussion, qi emphasizes generation and flow, while substance emphasizes congealing and reception. The two comparisons cannot be compressed into a single fixed ranking of strength.

The text criticizes inferring “fit to be cut down” or “must not be harmed” directly from the images of a great forest and a small seedling. Xu’s commentary further holds that these images originated as analogies used in Na Yin (纳音) and were distorted in later books. That account of their origin belongs to Xu’s commentary; the text itself only rejects the fixed image-based judgment and does not give the analogy’s history. The claim “Jia is a great tree and Yi is a seedling” therefore cannot be treated as a method for determining what to use in a chart established by this chapter.

Xu’s commentary also explains the difference in qi and substance through Jia’s yang firmness and Yi’s softness, and adds verses and comments on the favorable and unfavorable qualities of the ten Stems. These are further explanations of qualities and uses; they do not remove the text’s qualification that qi and substance are two distinct bases of comparison.

At the end, the text extends the account of Wood to the other phases, while singling out Earth’s “periods of flourishing within the four seasons.” This gives Earth a distinct role in the account of how the Five Phases form, while the distinctions of yin-yang, qi, and substance still apply. The text does not specify particular months or degrees of flourishing here; it cannot establish that Earth is equally flourishing in every month.