Yin and Yang in Equal Measure: The Way of Central Harmony and the Equilibrium of Day and Night at the Spring Equinox
This article offers a multi-dimensional exploration of the Spring Equinox (Chunfen) among the Twenty-Four Solar Terms, drawing on pre-Qin Confucian and Daoist philosophy, the original meanings of Chinese characters, and astronomical phenomena. By analyzing the character 'fen' (divide/equalize), the sun's alignment with the equator, and seasonal signs such as the return of swallows and the onset of thunder, it reveals the profound wisdom of 'central harmony' and the unity of Heaven and humanity embedded in the equinox's equal days and nights.
Chapter Nine: Second and Third Phenological Signs of the Spring Equinox -- Thunder Begins to Sound, Lightning First Appears: The Voice and Light of Yang
I. Why Does Thunder Sound at the Spring Equinox$12
The second sign of the Spring Equinox is "thunder begins to sound," and the third sign is "lightning first appears." Thunder and lightning are the two most spectacular forms in which yang energy manifests at the Spring Equinox. This chapter treats both signs together.
Why does thunder begin to sound around the Spring Equinox$13 The ancients understood this deeply. In pre-Qin yin-yang theory, thunder was understood as the product of the violent interaction and collision of yang and yin qi. In winter, yang lies hidden beneath the earth while yin reigns above; Heaven and Earth's qi is relatively quiet, hence no thunder. Around the Spring Equinox, the hidden yang qi strives upward with great force, meeting and violently colliding with the descending yin qi between Heaven and Earth -- this violent encounter erupts as thunder.
The Xici (Appended Statements) of the Book of Changes says: "Stirring them with thunder, moistening them with wind and rain." The "stirring" of thunder is the force by which Heaven and Earth rouse all things to revival. When spring thunder crashes, the yang energy that lay dormant all winter bursts forth completely, and all things, under this thunderous "stirring," awaken from hibernation and revive. This is why the solar term preceding the Spring Equinox is called "Awakening of Insects" (Jingzhe) -- hibernating creatures are startled awake by spring thunder. By the Spring Equinox, thunder grows louder and more frequent, and "thunder begins to sound" becomes the official phenological marker.
Worth pondering is that thunder was not merely a natural phenomenon but was endowed by the ancients with the import of "Heaven's majesty." The crash of thunder was seen as Heaven "raising its voice" -- though Heaven does not speak in words ("what does Heaven say$14"), it makes its presence and authority known through thunder.
II. "Lightning First Appears": The Manifestation of Light and the Distinction of Yin and Yang
The third sign of the Spring Equinox is "lightning first appears" -- the first flashes of lightning.
The ancients' distinction between thunder and lightning was exquisitely subtle. In their view, thunder is "sound" and lightning is "light"; thunder is the sonic manifestation of yang's surging energy, and lightning is the luminous manifestation. First comes thunder (second sign), then lightning (third sign) -- this sequence also reflects the ancients' careful observation: in their phenological experience, at the time of the Spring Equinox one first hears thunder, and only several days later sees lightning. From sound to light represents a further manifestation and intensification of yang energy.
The progression from "thunder begins to sound" to "lightning first appears" paints a picture of yang energy increasingly manifesting between Heaven and Earth and yin-yang interaction growing ever more intense. This is in perfect consonance with Dazhuang's image of "thunder above Heaven" and yang's robust vigor.
III. "Three Days Before the Thunder, Shake the Wooden Clapper-Bell to Announce to the People"
The Monthly Ordinances, in recording "thunder begins to sound," appends a most interesting decree: "Three days before the thunder, shake the wooden clapper-bell to announce to the people: 'Thunder is about to sound; those who do not discipline their conduct will bear children with defects, and calamity will surely follow.'"
Why did the ancients, on the eve of spring thunder, admonish the people to exercise restraint$15 This reflects a profound worldview of resonance between Heaven and humanity: spring thunder marks the moment when Heaven and Earth's qi is violently stirring and yang energy bursts forth at a peak of intensity. At such a moment, humans -- beings situated between Heaven and Earth -- should also bring their bodies and minds into harmony with the qi of Heaven and Earth. The ancients believed that to be unrestrained and indulgent at such a time would be to collide with and contravene the violently stirring qi of Heaven and Earth, disrupting one's own vital energies and thus affecting one's offspring.
IV. The "Majesty" of Thunder and Lightning and the "Benevolence" of Heaven and Earth
Spring thunder and lightning evoked a complex emotion in the hearts of the ancients -- both awe and gratitude.
On one hand, thunder and lightning symbolize "Heaven's majesty." On the other, they symbolize "Heaven's benevolence." The "stirring" of spring thunder rouses dormant creatures; thunder and lightning typically accompany spring rains that moisten the parched earth. What thunder and lightning bring is the revival and flourishing of life. From this perspective, thunder and lightning are the embodiment of Heaven and Earth's "benevolent" power -- they perform the benevolence of generation through the force of thunder.
This unity of "majesty" and "benevolence" is the ancients' profound understanding of the Way of Heaven. The Way of Heaven is both awesome (thunder and lightning shake, reward and punishment are clear) and benevolent (stirring all things, moistening all creation). Spring thunder and lightning at the equinox unite these two seemingly contradictory aspects of the Way of Heaven in a single phenological phenomenon.