Rotting Grass Transforms into Fireflies: The Philosophy of Metamorphosis and the Earth Virtue of Late Summer in the Great Heat
This article offers a deep reading of Great Heat (Dashu), the twelfth of the twenty-four solar terms, through the lenses of pre-Qin Confucian and Daoist philosophy, classical etymology, and astronomical phenology. It reveals the cosmic significance of the sun reaching ecliptic longitude 120°, when summer heat attains its zenith, and explores the Earth virtue of late summer, the metamorphosis of rotting grass into fireflies, and the hexagram Dun with its two rising yin lines — illuminating the ancient wisdom of reversal at the extreme and counterbalancing excess.
Chapter Three: The Month of Late Summer in the Monthly Ordinances: The Scene of Fire Virtue's Coming Retreat
I. The Nature of the Monthly Ordinances: A Manual for Heaven-Human Action
Among all pre-Qin texts, the most detailed and systematic description of Great Heat and its month of late summer belongs to the Monthly Ordinances (Yueling) of the Book of Rites (whose content closely parallels the "Late Summer Records" of the Lushi Chunqiu; scholars generally regard the two as sharing a common source). The Monthly Ordinances are not a simple calendrical record but a complete manual for heaven-human action — telling us, at each specific temporal node, what the celestial phenomena are, what the earthly signs are, and how human affairs should be conducted.
The Monthly Ordinances outlines the Five-Phase attributes of late summer: "Its days are bing and ding; its sovereign is the Flame Emperor; its spirit is Zhurong; its creature-class is the feathered; its note is zhi; its number is seven; its flavor is bitter; its odor is scorched; its sacrifice is to the hearth; at the sacrifice, the lungs are offered first."
This passage is identical to those for early and mid-summer, because the entire summer (all three months) belongs to Fire. Let us review this system of correspondences, paying special attention to the distinctive significance it assumes in late summer, at the "extreme of Fire" that is Great Heat:
"Its days are bing and ding" — The month of late summer corresponds to the Heavenly Stems bing and ding, which belong to Fire among the ten stems. But here lies a crucial foreshadowing: although the whole summer season has bing-ding Fire as its elemental assignment, late summer is also precisely the month when wu-ji Earth presides — this inner tension is the core of the "late summer Central Earth" question we shall treat at length.
"Its sovereign is the Flame Emperor; its spirit is Zhurong" — The presiding sovereign of late summer is the Flame Emperor (Yandi), and his attendant spirit is Zhurong. The Flame Emperor is named for "flame" (yan), a character composed of two "fire" radicals — fire upon fire, the very image of extreme heat. Zhurong is the fire god of high antiquity; the Classic of Mountains and Seas records: "In the south, Zhurong has the body of a beast and the face of a man, and rides two dragons." At Great Heat, the hottest moment of the year, the Fire virtue of the Flame Emperor and Zhurong is exerted to its utmost. Yet the more extreme the zenith, the nearer the turning — this is the reminder of pre-Qin dialectical thought.
"Its creature-class is the feathered" — The representative animal category of late summer is "feathered creatures," that is, birds. Birds soar through the sky, embodying the image of "ascending," consonant with fire's upward-moving nature. The fireflies of Great Heat's "rotting grass transforms into fireflies," though insects, are characterized by light emission and nocturnal flight — faint light and weightless flight, a lingering trace and transformation of Fire virtue at its most tenuous.
"Its note is zhi" — The musical tone of late summer is zhi, the most impassioned and elevated of the five tones (gong, shang, jue, zhi, yu), corresponding to fire's ardent quality. Yet it is particularly noteworthy that the pitch-pipe to which late summer "accords" is Linzhong — and Linzhong in the five-tone system corresponds to the gong tone, which corresponds to Earth. Here again fire and earth interweave, a point we shall discuss further in the chapter on pitch-pipes.
"Its number is seven" — Late summer's symbolic number is seven. In the pre-Qin numerological system, one and six are Water, two and seven are Fire, three and eight are Wood, four and nine are Metal, five and ten are Earth. Seven belongs to Fire, hence its assignment to summer.
"Its flavor is bitter" — Late summer's flavor is bitter. Among the five flavors (sour, bitter, sweet, pungent, salty) correlated with the Five Phases: sour belongs to Wood (spring), bitter to Fire (summer), sweet to Earth (late summer), pungent to Metal (autumn), salty to Water (winter). Bitter belongs to Fire — a point of central importance in Great Heat regimen: consuming bitter foods (such as bitter gourd, bitter tea, lotus-seed hearts) to purge excess fire is the wisdom of "using bitter to counter fire."
"Its odor is scorched" — Late summer's characteristic smell is the scorched odor, the smell of matter seared by fire, directly related to summer's affinity with Fire. At Great Heat, the "utmost of hot energy," heaven and earth seem pervaded by the acrid scent of being baked by a fierce sun.
"Its sacrifice is to the hearth; the lungs are offered first" — Late summer's sacrifice is to the hearth god, and the organ first offered is the lungs. The hearth is the place where fire is employed; to sacrifice by fire, to offer at the hearth in summer — the logic is entirely consistent.
II. The Son of Heaven's Conduct in the Month of Late Summer
The Monthly Ordinances prescribe the Son of Heaven's behavior in late summer in detail: "The Son of Heaven occupies the right wing of the Hall of Light, rides the vermilion carriage, drives red-bay horses, flies the red standard, wears vermilion robes, and dons red jade. He eats beans and chicken; his vessels are tall and coarse."
The Son of Heaven should dwell in the southwest wing of the Hall of Light ("right wing"), ride a red carriage, drive red horses, fly red banners, wear red garments, and wear red jade. All this red answers to the Fire virtue — summer belongs to Fire, and fire's color is red.
But note one detail: "occupies the right wing of the Hall of Light." The Hall of Light (Mingtang) was where the Son of Heaven conducted government in accord with the seasons, its chambers divided by Five-Phase directions. In early summer the Son of Heaven occupied the "left wing" (south-southeast); in midsummer, the "great temple" (due south); in late summer, the "right wing" (south-southwest). From left to center to right, the Son of Heaven's position within the southern side of the Hall shifted as summer progressed — this spatial movement symbolized Fire virtue's passage from rising (early summer) through zenith (midsummer) to impending decline (late summer). By late summer, the Son of Heaven had reached the "right wing" — the western end of the south; his next step would be the "center" (late summer Earth) and the west (autumn Metal). Spatial orientation precisely recorded the flow of time and the waxing and waning of cosmic energy.
III. The Edicts of Late Summer: Restraint and Nurture
The Monthly Ordinances specify the edicts to be issued in late summer, their tone closely attuned to the season's character: "In this month, the Fishing Master is ordered to slay flood-dragons, take alligators, register turtles, and capture soft-shell turtles. The Marshland Officers are ordered to collect timber and reeds." These are productive activities arranged in accordance with the late-summer phenology of abundant wetlands and thriving aquatic life.
The Ordinances further state: "In this month the earth is moist, the heat sultry; great rains descend in their season. Burn the cut weeds and channel the water — this is advantageous for killing weeds, as though with hot water. One may manure the fields, one may enrich the soil." This passage directly names Great Heat's core phenological condition — "the earth is moist, the heat sultry; great rains descend" — and arranges agricultural work accordingly: taking advantage of the humid heat and the rains, one burns the mown weeds, channels water for irrigation, and exploits this environment of combined moisture and heat ("as though with hot water") to eliminate weeds, compost organic matter, fertilize fields, and improve soil.
Here we see the ancients' supremely brilliant agricultural wisdom! They did not view Great Heat's humid heat as mere disaster but made full use of it — humid heat accelerates the decomposition of weeds and organic matter, so one burns weeds, composts, and improves soil at this time. The phrase "as though with hot water" is especially vivid: Great Heat's humid heat is like a pot of boiling water, able to "cook" weeds to mush and "steep" manure to maturity. This is precisely the power of "transformation" (hua) — and "transformation" is the fundamental function of the Earth virtue. The reason "the earth is moist, the heat sultry" favors composting and weed-rotting lies in the fact that Central Earth presides, and Earth governs transformation.
IV. The Monthly Ordinances' Warning: The Consequences of Untimely Edicts
After describing what should be done in late summer, the Monthly Ordinances sternly warn of the consequences of improper action: "If in late summer one issues spring edicts, the grain will be sparse and will fall early, the country will suffer wind-sickness and coughing, and the people will migrate. If one issues autumn edicts, the hills and lowlands will be flooded, the crops will not ripen, and many women will suffer calamity. If one issues winter edicts, winds and cold will come unseasonably, hawks and falcons will hunt too early, and the people of the four borders will flee into their strongholds."
The logical foundation of these warnings remains the core belief: each season has its specific "energy," and the nature of political edicts also carries specific "energy"; if the two do not accord, calamity follows. The late-summer warning specifically mentions: "If one issues autumn edicts, hills and lowlands will flood, and crops will not ripen" — in a season that should be given over to humid-heat transformation, prematurely imposing autumn's edicts of severity and contraction will instead cause flooding and crop failure. This reminds us: though Great Heat is hot, it is precisely the critical period when all things draw upon the humid heat to grow wildly, fill their grain, and mature. At this time "gathering" and "killing" are most to be avoided; one should accord with the Way of Heaven's "growing" and "transforming," allowing all things to complete their final expansion in the humid heat.
From a modern standpoint, the causal connection posited by this heaven-human resonance theory naturally lacks rigorous scientific basis. But its core insight — that agricultural timing must not be disordered, and that in a season of vigorous growth one must not impose the work of killing and harvesting — contains a simple yet profound agricultural and political wisdom.