Chapter 9 Yin-Yang and the Five Phases: The Virtue of Water, Heaven-One, and the Mutual Resonance of Yin and Yang Producing Rain

1. The Virtue of Water Within the Five Phases: North, Winter, Wisdom, Storage

To grasp the Yushui solar term in depth, we must understand the complete significance of "water" within the Five Phases system—what is called "the virtue of water" (shuide). Within the correspondence system of the Five Phases (Wood, Fire, Earth, Metal, Water), water is assigned to the North, to winter, to the color black, to wisdom, to storage, to the kidneys, and to the salty flavor.

Why are these correspondences of water so important for understanding the Yushui solar term$24 Because Yushui occupies a particularly delicate position: it belongs to spring (Wood), yet its core element is water. In other words, Yushui is the solar term in which "the virtue of water" exerts its influence within "the season of Wood," the point of handover between winter's virtue of water and spring's qi of Wood. To understand this handover, we must first understand the virtue of water itself.

The core of the virtue of water is "storage" (cang) and "wisdom" (zhi). Water is assigned to winter, and winter's characteristic is "storage"—the ten thousand things withdraw, lie hidden, and accumulate. Winter's water congeals and stores itself in the form of ice and snow, storing vital force deep within. This "storage" is not death, but the accumulation of energy for the coming year's "generation." At the same time, water is assigned to "wisdom"—as discussed earlier, "the wise delight in water"; water's flexibility, penetration, and depth symbolize wisdom. The "wisdom" of the virtue of water is a wisdom that lies deeply hidden, capable of both bending and extending—a wisdom of "great wisdom appearing as foolishness," of "the highest good being like water."

The mystery of the Yushui solar term lies here: it is the moment when the "virtue of water," stored through winter, begins transforming into the "qi of Wood" germinating in spring. In winter, water stores its vital force within ice and snow (the storage aspect of the virtue of water); during the Yushui season, that stored water begins flowing again, becoming spring rain, nourishing plants and trees (water begetting Wood). This is the concrete process of "water begets Wood" in the Five Phases' sequence of mutual generation: the energy stored by winter's water, through the spring rain of the Yushui solar term, transforms into the germinating power of spring's Wood. Thus the Yushui solar term is the transition from the virtue of water to the qi of Wood, the transformation from "storage" to "generation," the sublimation of winter's wisdom into spring's vitality.

2. Revisiting "Heaven-One Begets Water": The Profound Meaning of Water as First Among the Five Phases

We have mentioned "Heaven-One begets water" several times in earlier chapters. Here let us examine it once more, more deeply, from the perspective of the Five Phases' generative sequence.

The "Treatise on Pitch-Pipes and the Calendar" in the Book of Han records the sequence of the Five Phases' generation: "Heaven, by One, begets Water; Earth, by Two, begets Fire; Heaven, by Three, begets Wood; Earth, by Four, begets Metal; Heaven, by Five, begets Earth." In this sequence, water is begotten by "One," the first of the Five Phases, the beginning of the ten thousand things. And "One" holds a supreme position in Chinese philosophy—Laozi says, "The Way begets One"; "One" is the first, and the most fundamental, thing begotten by the Way. That water is begotten by "One" means that water is the element closest to the "Way," closest to the primordial origin.

Why does this matter so much for the Yushui solar term$25 Because it reveals the special status of the Yushui solar term within the entire cosmic picture of generation. If the sequence of a year's seasons is a miniature reenactment of the process by which Heaven and Earth are generated, then the Yushui solar term—the moment when water becomes active once more, the first to awaken—corresponds precisely to "Heaven-One begets water," the very beginning of the generation of all things. Each year's Yushui is an overture to Heaven and Earth's "creation": water (begotten by Heaven-One, the beginning of the ten thousand things) revives first, and only then unfold, in sequence, Wood (plants and trees sprouting), Fire (summer's heat), Metal (autumn's severity), and Earth (late summer's transformative nurture). The Yushui solar term thus carries the cosmological dignity of "the beginning of the ten thousand things"—it is the true starting point of a year's cycle of life.

There is also a numerical symbolism worth pondering here. Water's "generative number" is one, and its "completion number" is six (one plus the Five Phases' governing number, five); Wood's "generative number" is three, and its "completion number" is eight. The Yushui solar term falls precisely at the transition from "water's one and six" to "wood's three and eight." This numerical progression (from one to three, from six to eight) symbolizes the advance of vital force from "the hidden origin" (water's one) toward "the germinating form" (wood's three). Yushui is the crucial turning point of this advance—it is both the end of water (the final blossoming of winter's virtue of water) and the beginning of wood (the first germination of spring's qi of wood).

3. Yin and Yang in Mutual Resonance, Producing Rain: A Philosophical Explanation of Rain's Origin

The core of the Yushui solar term is "rain." From the perspective of pre-Qin yin-yang theory, how, precisely, does rain form$26 Pre-Qin thinkers had their own profound answer to this question.

Within pre-Qin cosmology, rain is the product of "the mutual resonance of yin and yang." The "Great Treatise, Part 1" of the Book of Changes says: "Heaven and Earth intermingle in dense vapor, and the ten thousand things are transformed and matured." The qi of Heaven and Earth intermingles and intertwines densely, and within this intermingling, the ten thousand things are transformed, nurtured, and brought to maturity. And rain is precisely one of the most direct manifestations of "Heaven and Earth intermingling in dense vapor." Specifically: the yin qi of the earth (water vapor), heated and evaporated by yang qi, rises upward; the yang qi of Heaven, meeting the rising yin qi high in the sky, resonates and condenses with it, thereby forming clouds; within the clouds, the yin and yang qi further resonate and condense, thereby transforming into rain and falling to earth. This entire process is one act of resonance and merging between yin (water vapor, earthly qi) and yang (heat, heavenly qi).

This explanation accords perfectly with the Tai hexagram's "Heaven and Earth interacting," discussed in Chapter Seven. The formation of rain is, in essence, "Heaven and Earth interacting"—yang qi rising, yin qi descending, the two meeting and resonating in between. This is why the Tuanzhuan commentary on the Qian hexagram says "clouds move and rain is bestowed"—the bestowal of rain is the result of the resonance between Qian's originating power (Heaven's yang qi) and Kun's originating power (Earth's yin qi). Rain is the crystallization of yin and yang in harmony; every drop of rain is water of life, conceived through one act of "union" between Heaven and Earth.

This notion of "yin and yang resonating to produce rain" contains within it an exceedingly profound philosophy of life. In the ancients' view, the generation of life always arises from the resonance of the two qi of yin and yang—male and female resonate to produce humans, female and male animals resonate to produce offspring, Heaven and Earth resonate to produce rain, and rain in turn nourishes and gives birth to the ten thousand things. Rain thus becomes the product of the grandest "union of life" between Heaven and Earth, the most intuitive symbol of yin and yang's harmonious generation of the ten thousand things. The Yushui solar term, as the season when the first spring rains fall and yin and yang resonate on a grand scale, is thereby endowed with the sacred significance of "the union of Heaven and Earth, gestating the ten thousand things." Small wonder that later ages called a timely spring rain the "grace and favor" of Heaven and Earth—for it truly is the essence of life, conceived through the resonance of Heaven and Earth, nourishing all things.

4. Water Overcomes Fire, Fire Begets Water: The Mystery of Summer Rain and the Dialectic of Water

Here we must address a question that seems contradictory but is in fact profound, one that can help us understand more fully the dialectical position of water within yin-yang and the Five Phases.

According to the logic of the Five Phases' mutual overcoming, water overcomes fire. Water (belonging to winter, to yin) and fire (belonging to summer, to yang) should therefore be mutually opposed, mutually restraining. Yet the Yushui solar term, as a solar term of spring, falls precisely at the transition between water (winter) and fire (summer)—on the one hand continuing winter's virtue of water (rain is, after all, water), and on the other foreshadowing the growth of yang qi (the herald of fire). The water of the Yushui season is no longer the purely yin, congealed, dead water of winter, but living water, roused and set flowing anew by the returning yang qi (the germination of fire). In other words, the water of Yushui is water that contains yang within yin, that harbors fire within water—it is the intermediate link in the transition from winter's purely yin virtue of water to summer's purely yang virtue of fire.

This dialectical relationship of "harboring fire within water, containing yang within yin" finds perfect expression in the image of the Kan hexagram. As discussed earlier, the Kan hexagram (☵) is a single yang line dwelling between two yin lines—yin on the outside (the softness of water), yang contained within (the firmness of fire). This symbolizes precisely the essential nature of water: though water belongs to yin, it harbors within it the power of yang; though water is utterly soft, it harbors within it inner vigor. The water of Yushui is the finest portrait of this water that "contains yang within yin, harbors firmness within softness"—that seemingly gentle spring rain in fact harbors the returning yang qi, harbors a vigorous power that rouses all things and dissolves solid ice.

Understanding this, we can grasp the following: although the Yushui solar term centers on "water," it is by no means a mere continuation of winter's dead water, but rather the moment when water, activated by yang qi, bursts anew with vitality. It is the product of yin and yang's mutual resonance (yin and yang resonating to produce rain), the link in the transition from the virtue of water to the qi of wood (water begetting wood), the revival of living water that contains yang within yin, that harbors firmness within softness. The dialectic of the water of Yushui is, in the final analysis, a dialectic of "generation" (sheng)—through the resonance and transformation of yin and yang, of water and fire, of softness and firmness, it gives rise to the annual renewal of life between Heaven and Earth.