Chapter 7 The Book of Changes and Yushui: Clouds Moving and Rain Bestowed, and the Water-Image of the Kan Hexagram

1. The Twelve Sovereign Hexagrams and the First-Month Tai Hexagram: "Three Yang Lines Open Prosperity"

The Book of Changes is an encyclopedia of pre-Qin thought, containing the most profound insight into the laws governing the cosmos. Although the Book of Changes does not directly discuss the solar terms, its system of hexagram images bears a deep correspondence to the succession of the four seasons. The first month (yin month), in which the Yushui solar term falls, corresponds, within the system of the Twelve Sovereign Hexagrams, to the Tai hexagram (䷊).

The Twelve Sovereign Hexagrams correlate twelve hexagram images with the twelve months, displaying the process by which yin and yang wax and wane over the course of a year: the eleventh month is Fu (Return, one yang line born); the twelfth month is Lin (Approach, two yang lines growing); the first month is Tai (Peace, three yang lines opening prosperity); the second month is Dazhuang (Great Strength, four yang lines flourishing); the third month is Guai (Resolution, five yang lines cutting away yin); the fourth month is Qian (six yang lines, pure yang); the fifth month is Gou (Encounter, one yin line born); the sixth month is Dun (Retreat, two yin lines growing); the seventh month is Pi (Obstruction, three yin lines); the eighth month is Guan (Contemplation, four yin lines); the ninth month is Bo (Splitting Apart, five yin lines); and the tenth month is Kun (six yin lines, pure yin).

That the first month, in which Yushui falls, corresponds to the Tai hexagram is a key to understanding the cosmic significance of Yushui. The image of the Tai hexagram is Qian below and Kun above (䷊)—the lower three lines are Qian (☰, Heaven), and the upper three lines are Kun (☷, Earth). That is, in the Tai hexagram, "Earth is above and Heaven is below." This is the famous "three yang lines opening prosperity" (san yang kai tai).

Why should "Earth above, Heaven below" constitute "Tai" (prosperity, smooth flow)$12 This seems to defy common sense—Heaven is naturally above and Earth naturally below, so how could inverting them be auspicious$13 This is precisely where the Book of Changes' most profound dialectical wisdom lies. The Tuanzhuan commentary on the Tai hexagram says: "Tai: the small departs and the great arrives; good fortune and smooth progress. This is because Heaven and Earth interact, and the ten thousand things flow through; those above and below interact, and their wills are united."

The key lies in the three characters "Heaven and Earth interact" (tiandi jiao). Heaven's nature is to rise (yang qi ascending), and Earth's nature is to sink (yin qi descending). If Heaven remains above and Earth remains below, then Heaven continues to rise and Earth continues to sink, and the two grow ever farther apart, never meeting—this, rather, would be "Pi" (obstruction, blockage). But in the Tai hexagram, with "Earth above and Heaven below," it means: the yin qi of Earth sinks downward, while the yang qi of Heaven rises upward, and the two meet, resonate, and merge in the middle—this is "Heaven and Earth interact, and the ten thousand things flow through." Only when the qi of Heaven and Earth interact and merge can the ten thousand things flow and grow.

This corresponds remarkably closely to the inner spirit of the Yushui solar term. How does rain form$14 Heaven's yang qi causes the water vapor rising from the ground's surface to ascend, meeting and condensing with the yin qi high above, and then falling as rain. This process is precisely "Heaven and Earth interacting"—the rising yang qi and the descending yin qi meeting and resonating high in the sky. In other words, rain itself is the product of "Heaven and Earth interacting," the most direct material manifestation of the Tai hexagram's principle that "Heaven and Earth interact, and the ten thousand things flow through." That the Yushui solar term falls at the time of the first-month Tai hexagram is by no means coincidental—it marks precisely the moment when the qi of Heaven and Earth begins to interact on a grand scale, thereby giving rise to all things. Three yang lines open prosperity, Heaven and Earth interconnect, and so clouds move and rain is bestowed, and so the manifold things flow into form.

2. "Clouds Move and Rain Is Bestowed, and the Manifold Things Flow into Form": The Rain-Water Image of the Qian Hexagram

The Tuanzhuan commentary on the Qian hexagram in the Book of Changes contains a line that might almost have been written expressly for the Yushui solar term: "Great indeed is the originating power of Qian! The ten thousand things depend on it for their beginning, and it governs the whole of Heaven. Clouds move and rain is bestowed, and the manifold things flow into form."

Great indeed is the qi of Qian's originating power! The ten thousand things depend upon it to begin their life, and it governs the entire Way of Heaven. Clouds move across the sky; rain falls to nourish the earth; and each of the ten thousand things takes on its own particular shape.

Let us look closely at these eight characters: "clouds move and rain is bestowed, and the manifold things flow into form." "Clouds move"—clouds move and flow across the sky; "rain is bestowed"—rain falls and spreads across the earth; "the manifold things flow into form"—the ten thousand things (the manifold things) flow and generate their respective shapes. These eight characters place "rain" at the very core of the generation of all things: it is precisely because there is "the bestowal of rain" that the ten thousand things are able to "flow into form." Without the nourishment of rain water, the qi of Qian's originating power, great though it may be, could never be realized into concrete, formed life. Rain is the bridge connecting the abstract "qi of Qian's originating power" with the concrete "forms of the ten thousand things."

Why "flow into form" rather than simply "take form"$15 This character "flow" (liu) is exceedingly subtle. It implies that the forms of the ten thousand things are not rigidly, once-and-for-all "completed," but are, under the nourishment of spring rain, flowing, growing, and continually being generated. A plant, under the spring rain, sprouts, unfurls its leaves, and grows joint by joint day by day—its "form" is generated gradually, in flow. And what drives this "flowing into form" is precisely the flowing water (rain). The "flow" of water gives rise to the "flowing completion" of the forms of the ten thousand things. The Yushui solar term is precisely the moment when the grand overture of this "flowing into form of the manifold things" begins to unfold.

At a deeper level, "clouds move and rain is bestowed" also reveals a core conviction of pre-Qin cosmology: rain is not an isolated meteorological phenomenon, but the concrete manner in which "Qian's originating power" (the Way of Heaven) enacts its virtue of generating and nurturing life. How does the Way of Heaven (Qian's originating power) "provide the ten thousand things with their beginning"$16 Precisely through "clouds moving and rain being bestowed." In other words, rain is the material vehicle of the Way of Heaven's virtue—Heaven, by sending down rain, extends its virtue of generation and nurture to the earth and the ten thousand things upon it. This provides the deepest foundation, in the Book of Changes, for the later notion of "using rain as a metaphor for virtue" and "grace and favor like rain." The grace of Yushui is, in essence, the virtue of the Way of Heaven itself.

3. The Kan Hexagram: The Image of Water and "Its Heart Alone Flows Through"

Among the sixty-four hexagrams of the Book of Changes, the one dedicated specifically to the image of "water" is the Kan hexagram (☵, ䷜). The image of the Kan hexagram is a single yang line dwelling between two yin lines (☵), symbolizing water—soft on the outside (the two yin lines above and below) yet firm within (the single yang line in the middle).

Why symbolize water as "soft outside, firm within"$17 This is an exceedingly profound insight. Water appears to be utterly soft (as discussed above), yet within it is contained a power of utmost firmness—that central yang line symbolizes precisely water's inner vigor, its ability to "enter where there is no gap, having no substance" and to "gallop through the hardest thing under Heaven." The essence of water is firmness concealed within softness, strength contained within weakness. The image of the Kan hexagram captures this duality of water with precision.

The Tuanzhuan commentary on the Kan hexagram in the Book of Changes says: "Doubled Kan means repeated dangers. Water flows without ever becoming full; it moves through danger without losing its trustworthiness. That its heart alone flows through is due to its firmness at the center." The Kan hexagram symbolizes danger upon danger. Water flows and never overflows to excess ("flows without becoming full"); it advances through dangerous terrain, yet never loses its own trustworthiness ("moves through danger without losing its trustworthiness"). The reason it is able to "keep its heart flowing through" (maintain inner smoothness) is that it possesses "firmness at the center"—the inner vigor represented by that central yang line.

This passage's depiction of water is exceedingly profound, and resonates deeply with the spirit of the Yushui solar term. "Water flows without ever becoming full"—water is forever flowing, never stagnant, never self-satisfied. This is precisely a portrait of the streams reviving and flowing ceaselessly during the Yushui season, and another expression of the Master's "what passes away is like this, never ceasing day or night." "It moves through danger without losing its trustworthiness"—even in the most perilous circumstances (crossing gorges, plunging over cliffs), water always follows its own nature (flowing downward), never betraying its own "trustworthiness." This is precisely the Book of Changes' own expression of the "trustworthiness of water" discussed earlier. "That its heart alone flows through is due to its firmness at the center"—water is able to maintain its inner smoothness amid repeated dangers entirely because of its inner vigor (firmness concealed within softness).

The wisdom of the Kan hexagram tells us: true water is not feeble or powerless, but firm within softness, yielding without yet vigorous within. During the Yushui season, that seemingly gentle spring rain in fact contains within it a vigorous power that rouses all things, dissolves solid ice, and gives rise to life everywhere. We must see both water's softness (excelling in benefiting the ten thousand things without contending) and water's firmness (the inner vigor of the Kan hexagram's central line)—only thus can we fully understand water's dual character, and fully understand the profound meaning contained within the Yushui solar term: "softness that nourishes things, firmness that opens up life."

4. "Water over Fire, Already Completed" and "Fire over Water, Not Yet Completed": The Position of Water at the Close of the Hexagram Sequence

The arrangement of the sixty-four hexagrams of the Book of Changes opens with Qian and Kun, and closes with the two hexagrams "Jiji" (Already Completed) and "Weiji" (Not Yet Completed). This arrangement carries deep significance, and water (the Kan trigram) is a crucial component of these two concluding hexagrams.

The sixty-third hexagram, "Jiji" (䷾), has the image of Li below and Kan above (Fire below, Water above)—that is, water above fire. The sixty-fourth hexagram, "Weiji" (䷿), has the image of Kan below and Li above (Water below, Fire above)—that is, fire above water. Why should these two opposing hexagrams of water and fire conclude the entire Book of Changes$18

In the Jiji hexagram, with water above fire, water's nature is to move downward and fire's nature is to blaze upward, and so the two move toward one another and merge into completion—hence it is called "Jiji" (already succeeded, already completed). This symbolizes a state of fullness and completion—water and fire merging, yin and yang in harmony, all affairs already accomplished. Yet the Book of Changes does not take the fullness of "Jiji" as its final destination, but arranges the "Weiji" hexagram after it—water below and fire above, the two moving in opposite directions, not yet merged, hence "Weiji" (not yet completed). Concluding the entire Book of Changes with "Weiji" means this: the operation of the cosmos has no true endpoint; fullness (Jiji) always returns again to incompletion (Weiji), and then a new cycle begins anew.

This concluding arrangement resonates deeply with the cyclical cosmology embodied in the Yushui solar term. Water plays a crucial role in these two hexagrams—it is the key to both "Jiji" (fullness) and "Weiji" (the cycle beginning anew). The Yushui solar term is precisely the manifestation, within the yearly sequence, of this "cycle beginning anew": winter is a kind of "Jiji"-like fullness of storage and withdrawal (yin and yang settling into stillness), while the Yushui solar term is a kind of "Weiji"-like new beginning (yin and yang resonating anew, the ten thousand things germinating afresh). The flow of water, the arrival of rain, mark the moment the qi of Heaven and Earth passes from the fullness of stillness back into the cycle of flow. That the Book of Changes concludes with the two hexagrams of water and fire, returning to "Weiji," is precisely meant to tell us: the Way of Heaven and Earth generates life ceaselessly, without end—and each year's Yushui solar term is one solemn activation, in spring, of this Way of "ceaseless generation."