《天原發微》Vol. 6

Volume 6 of the Tianyuan Fawei (Subtle Origins of Celestial Principles) examines the concept of "Six Affective States," compiled by Yuan dynasty scholar Bao Yunlong (courtesy name Jingxiang) and edited by Fang Hui (sobriquet Xugu). This section primarily explores the theory of the Four Images from the Yijing (Classic of Changes).

The Yijing states that the Two Modes (Liangyi, Yin-Yang) generate the Four Images (Sixiang), yet interpretations have varied across dynasties. Eminent Confucians like Wang Bi (courtesy name Fusi) and Cheng Yi (sobriquet Yichuan) held differing views. Only Shao Yong (Shao Kangjie)'s transmission of the Innate (Xiantian) learning could resolve this millennium-old conundrum. Zhu Xi had already elucidated this thoroughly in his Yixue Qimeng (Introduction to Yi Studies), yet some still fail to comprehend. In truth, grasping eight key characters unlocks the entire volume.

The Yijing speaks of five celestial numbers and five terrestrial numbers, preserving one fundamental principle while employing four transformations. In divination, these manifest as 7, 8, 9, 6; in geography as water, fire, earth, stone; in astronomical observation as sun, moon, stars, and constellations; and in trigrams as the Eight Bagua—merely different applications of the same principle.

Shao Yong maintained that nothing surpasses Heaven and Earth among all phenomena. Heaven's essence lies in the transformations of Yin-Yang, forming the four seasons; Earth's essence in the interweaving of hardness and softness (Gang-Rou), shaping the four directions (Siwei). Qian represents all yang phenomena, Kun all yin phenomena—Heaven and Earth being the supreme embodiments of Yin-Yang. Through the waxing and waning of Yin-Yang and the alternation of cold and heat, Heaven establishes the four seasons—this is the Dao of Heaven. Through the interplay of hardness and softness, level and rugged terrain, Earth forms the four directions—this is the principle of Earthly patterns. The Four Images manifest in celestial phenomena as constellations, in annual cycles as seasons, in topography as directions—all constituted by the dual qi of Qian-Kun and Yin-Yang.

Cheng Yi interpreted the Four Images as Yin, Yang, hardness, and softness: Yin-Yang generates Heaven, hardness-softness generates Earth. Zhu Xi supplemented this, noting Shao Yong's mathematical derivation beginning with one Yin and one Yang. Heaven's Four Images divide into Great Yang (Taiyang), Great Yin (Taiyin), Lesser Yang (Shaoyang), and Lesser Yin (Shaoyin)—corresponding to sun, moon, stars, and constellations. Earth's Four Images comprise Great Hardness (Taigang), Great Softness (Tairou), Lesser Hardness (Shaogang), and Lesser Softness (Shaorou). The interaction of Yin-Yang produces Heaven's Four Images, while the interaction of hardness-softness yields Earth's Four Images.

This passage explains the fundamental principles of cosmic generation. Initially, there exists only the Taiji (Supreme Ultimate, the cosmic origin), which then divides into the two Qi (energies) of Yin and Yang, further differentiating into the Four Symbols (four basic states), and ultimately evolving into the Bagua (Eight Trigrams). Both heaven and earth contain complete systems of the Four Symbols, each embodying the operational laws of Taiji, which ultimately manifest as the cyclical movements of the Five Phases (Wood, Fire, Earth, Metal, Water).

Regarding the composition of the Chinese character "易" (Yi, meaning "change"): its upper part "日" represents Yang (the sun), while its lower part "月" represents Yin (the moon). This is why Zhuangzi stated that the "Yijing" (Book of Changes) elucidates the Dao of Yin-Yang. Shao Yong, a Northern Song Dynasty Neo-Confucian scholar, proposed: the Great Yang is represented by the sun, the Great Yin by the moon, Lesser Yang by the stars, and Lesser Yin by the hour of Chen (time). The interwoven movements of the sun, moon, and stars constitute the complete system of heaven. Water represents ultimate softness, fire represents ultimate hardness, earth represents secondary softness, and stone represents secondary hardness—the interactions of these four form the complete manifestation of earth.

Shao Bowen (Shao Yong's son) explained: The classic "Huangji Jingshi" replaces the traditional Five Phases of "Metal, Wood, Water, Fire, Earth" with "Water, Fire, Earth, Stone" because the former represent primordial forms while the latter represent applied forms. The primordial forms are the root of the Five Phases—metal comes from ore, and wood originates from soil. When the Five Phases operate between heaven and earth, they inherently contain the essence of water, fire, earth, and stone.

The specific correspondences are as follows: The sun corresponds to the Qian trigram in the due south position, the moon to the Dui trigram in the southeast; stars correspond to the Li trigram in the east, while the hour of Chen corresponds to the Zhen trigram in the northeast. Water corresponds to the Kun trigram in the due north, fire to the Gen trigram in the northwest; earth corresponds to the Kan trigram in the west, and stone to the Xun trigram in the southwest. Among celestial phenomena, the sun belongs to Yang and the moon to Yin, with stars being strong and the hour of Chen gentle. Among terrestrial phenomena, water belongs to Yin and fire to Yang, with earth being gentle and stone strong. The celestial image manifests as the sun, while the earthly substance manifests as fire—in essence, fire and the sun share the same origin, which is why ancient yangsui (solar ignition tools) could extract fire from sunlight.

This scripture elucidates the correspondences and interactions between heaven, earth, and all things. The sun manifests as the image of fire in heaven and takes form as the moon on earth; the moon manifests as the image of water in heaven and appears as water on earth. Water and the moon share the same essence, which is why the ancients could collect water by holding a square water-catching vessel (fangzhu) toward the moonlight.

Similarly, stars manifest as celestial constellations in heaven and appear as stones on earth; the Polar Star (Chenxing) manifests as the image of time in heaven and takes form as soil on earth. Beyond the sun, moon, and stars, the vast expanse of the sky belongs to the domain of time; beyond water, fire, soil, and stones, the boundless earth belongs to the category of soil. The sun, moon, and stars resemble human eyes, ears, mouth, and nose, while water, fire, soil, and stones are like human blood, qi, bones, and flesh—these constitute the physical forms of heaven and earth. Yin-Yang and hardness-softness resemble human spirit (shen), serving as the fundamental source that generates these physical characteristics.

The scripture further explains: The sun brings summer heat, the moon brings winter cold, stars govern daylight, and the Polar Star governs nighttime. The alternation of heat, cold, day, and night constitutes the transformations of heaven. Water transforms into rain, fire into wind, soil into dew, and stones into thunder. The convergence of rain, wind, dew, and thunder forms the transformations of earth. Summer heat alters the innate nature of all things, winter cold modifies their emotional states, daylight changes their forms, and nighttime transforms their physical substance. Together, these changes influence the responses of plants and animals.

Rain nourishes walking creatures, wind strengthens flying birds, dew fosters grasses, and thunder stimulates trees. The growth and development of walking creatures, flying birds, grasses, and trees all represent responses to the transformations of heaven and earth. The sun, moon, and stars influence all things through heat, cold, day, and night, while water, fire, soil, and stones transform the earth through rain, wind, dew, and thunder. The changes of heaven guide the transformations of earth, and earth's transformations in turn resonate with heaven's changes—this call-and-response allows all things to come into being.

Heat, cold, day, and night affect the nature, emotions, forms, and bodies of all things, while rain, wind, dew, and thunder alter the growth of walking creatures, flying birds, grasses, and trees. The nature, emotions, forms, and bodies of all things originate from heaven and resonate with earth, whereas walking creatures, flying birds, grasses, and trees originate from earth and respond to heaven. This mutual resonance and reciprocal interaction constitute the operating principles of heaven and earth and the natural order of all things' growth.

Heaven belongs to the Yang category, earth to the Yin category. Yang governs movement, Yin governs stillness. The Yang within Yang manifests as flying birds (intimate with heaven), while the Yin within Yang appears as walking creatures (close to earth). Heaven contains the purest qi, earth holds the most refined substance. Humans are the most enlightened and intelligent beings; among flying birds, the phoenix (luanfeng) stands as their representative; among walking creatures, the qilin serves as their emblem; among shelled creatures, the turtle and dragon are exemplary; among grasses, the lingzhi mushroom and orchid are preeminent; among trees, pine and cypress are paramount.

This scripture primarily explores the operational principles of heaven, earth, and all things, as well as the Dao of Yin-Yang transformation.

Between heaven and earth exist extreme phenomena: the heavens manifest the most violent meteorological events, while the earth contains the most profound depths. Humans may transform into demons, birds into ominous creatures (like owls), beasts into tigers and wolves, insects into venomous serpents, plants into toxic vegetation, and stones into hardened gravel. All things have their predetermined cycles—when these cycles are exhausted, phenomena perish; where phenomena exist, cycles must exist, and when phenomena end, their cycles conclude. Heaven and earth nurture all things differently, thus their various interactions create transformations.

Shao Yong (a Northern Song Confucian scholar) proposed: The sun's movement follows the principle of "one," the moon follows "two," the year follows "three," and time periods follow "four." "One" represents the cosmic cycle (Yiyuan), "two" signifies the twelve earthly branches cycle, "three" denotes the 360 days, and "four" corresponds to 4,320 time periods—this is described from the perspective of one year.

The celestial operational principles are: the sun follows the celestial sphere's rotation, the moon follows the sun's movement, and the stars follow the moon's manifestation. Thus stars emulate the moon, the moon emulates the sun, and the sun emulates the celestial sphere. The celestial sphere is half-bright and half-dark; the sun moves with varying speeds; the moon waxes and wanes; stars exhibit motion and stillness—all manifesting the Dao of Yin-Yang transformation. Although the sun appears to move rightward, it actually follows the celestial sphere's leftward rotation; though the moon moves swiftly, it always follows the sun; stars follow the moon primarily manifesting at night. The interplay of one Yin and one Yang embodies the Dao (the Way).

The celestial sphere emulates the Dao through its half-bright/half-dark nature; the sun emulates heaven through alternating speeds; the moon emulates the sun through phases; stars emulate the moon through motion and stillness. Where "one" exists, "two" must follow—neither solitary Yin nor Yang can exist independently. The sun's speed variations manifest as faster movement in Yang positions and slower in Yin positions; stellar motion appears as planetary movement (Weixing) versus fixed stars' (Jingxing) stillness. Cai Yuanding (a Song dynasty scholar) explained: The sun determines orbital paths, the moon governs lunar phases, stars divide into fixed and planetary, while Chen refers to the twelve celestial meeting points of sun and moon (zodiac signs).

The celestial sphere remains constantly visible day and night, yet the sun appears only by day, the moon only by night (and remains invisible half the time), while stars manifest partially at night—revealing celestial hierarchy. Though half-bright/half-dark, the celestial sphere is always visible; the sun necessarily dominates daytime skies, while the moon sometimes dips below horizons at night making it half-invisible, and stars appear less distinctly than the moon. This hierarchy manifests as higher encompassing lower, greater containing lesser. Partial stellar visibility occurs because the five planets and twenty-eight constellations appear in rotation.

The moon can also be seen by day, thus belonging to Yang-within-Yin (the feminine within masculine); stars appearing at night represent Yin-within-Yang (the masculine within feminine). This further illustrates the principles of mutual containment and transformation between Yin and Yang.

This passage expounds the Daoist philosophical understanding of celestial Yin-Yang transformations and the formative principles of the Yi Jing (Book of Changes) hexagrams.

Regarding the Yin-Yang attributes of celestial bodies: while the moon belongs to Yin, its visibility during daylight makes it "Yang within Yin"; stars visible at night represent "Yang within Yin"; whereas Chen (referring to polar stars and other fixed celestial bodies), though invisible to the naked eye, bear the movement of other stars and thus embody "Yin within Yin." The author particularly notes that although Chen stars remain unseen, the sky that carries them is perpetually visible, hence one should not consider Chen stars in isolation but regard the celestial dome as the fundamental whole.

Zhu Xi (Master Zhu) explained the formation of Yi Jing hexagrams thus: the initial stroke divides into the two modes of Yin and Yang, the second stroke forms the four phenomena (Great Yang, Lesser Yin, Lesser Yang, Great Yin). Specifically:

• Great Yang corresponds to the number 9
• Lesser Yin corresponds to 8
• Lesser Yang corresponds to 7
• Great Yin corresponds to 6

These numbers resonate with the patterns found in the Hetu (River Chart) and Luoshu (Luo Writing), ancient mystical numerical diagrams. For instance, in the Hetu, 6 derives from 1 plus 5, 7 from 2 plus 5, and so forth. Zhou Dunyi (Master Zhou) and Shao Yong (Master Shao) employed these principles to interpret the transformations of the Five Phases (Wood, Fire, Earth, Metal, Water) and the four seasons.

The Eight Trigrams (Bagua) form by adding another stroke to the four phenomena, creating three-line symbols corresponding to eight directions: Qian (Heaven), Dui (Marsh), Li (Fire), Zhen (Thunder), Xun (Wind), Kan (Water), Gen (Mountain), and Kun (Earth). Addressing queries about discrepancies with Zhu Xi's sequence of drawing hexagrams, the author clarifies that Zhu's interpretation actually originates from Shao Yong's theory of Prenatal Yi studies, though earlier scholars hadn't explicitly stated this connection.

This passage demonstrates the distinctive Daoist mode of thought that integrates astronomical observation, numerical mysticism, and philosophical reflection, using the waxing and waning of Yin-Yang to explain cosmic operations.

The Tianyuan Fawei scripture primarily explores the relationship between Yin-Yang transformations and celestial phenomena, and how to predict auspicious or inauspicious events by observing these patterns. The text states that all transformations between heaven and earth can be summarized through the Four Symbols (Shaoyang [Lesser Yang], Taiyang [Greater Yang], Shaoyin [Lesser Yin], and Taiyin [Greater Yin]), manifestations that permeate all existence. In the Yijing (Book of Changes), these transformations correspond to the numbers seven, eight, nine, and six, each representing distinct states of Yin and Yang.

Celestial bodies like the sun, moon, and stars also embody Yin-Yang transformations: The sun (Taiyang) represents ultimate Yang, manifesting through seasonal and diurnal cycles of heat and cold; Shaoyang (stars) represents dispersed solar light without intrinsic change; the moon (Taiyin) displays waxing and waning through its phases; while Shaoyin (celestial markers) constitutes the unchanging heavenly framework without formal variation. These celestial phenomena resemble the "yao lines" (constituent trigrams) inscribed in the sky, while the hexagrams themselves represent concealed celestial patterns.

Fuxi created the Bagua (Eight Trigrams) by observing celestial phenomena, while Confucius comprehended the principles of the manifest and hidden by studying astronomy. Divination through the Yijing not only predicts mundane affairs but also reveals the fundamental operations of the Dao between heaven and earth.

Regarding the sun (Taiyang), the text cites various schools: The sun belongs to the Li trigram (one of the Bagua), symbolizing fire. As the quintessential essence of southern fire Qi (vital energy), fire has no form but attaches to physical substances, while the sun represents its celestial manifestation. Though structurally Yin (as the Li trigram is Yin), the sun functionally operates as Yang, hence illuminating daylight. Ancient texts like the Yaodian (Canon of Yao) and Yueling (Monthly Ordinances) document correlations between solar movements and temporal cycles.

The sun begins its ascent at midnight (Zi hour), symbolizing vital energy and universal clarity; after noon (Wu hour) it descends, representing decline and cosmic quiescence. This very rhythm constitutes the mechanism of spirit operations. The Yuanming Bao states the sun's perfect circular form illuminates a thousand li, inspiring ancient kings to model their capital domains after this solar radiance.

Cheng Yi proposed that heaven, earth, sun and moon share one essence, with moonlight being reflected sunlight. Shao Yong advanced the concept of "Yang embracing Yin to form the sun," which Zhu Xi further clarified: The ceaseless movement of Qian (pure Yang trigram) constitutes the fundamental substance, while the cyclical interactions of sun, moon and seasons represent its functional manifestations—where substance exists, function necessarily appears.

This scripture primarily elucidates the celestial patterns of heaven and earth's movements and the transformations of Yin-Yang from an astronomical perspective. The text begins by noting that heaven envelops earth, with earth being relatively small while the sun is immense. Sunlight emerges from the four directions of the earth's surface, while the moon in the sky receives solar illumination to manifest its waxing and waning phases—appearing full when distant from the sun and diminished when near it.

The Han dynasty scholar Zhu Hanshang proposed that heaven and earth achieve harmony through the interaction of the Kan (Water) and Li (Fire) trigrams. When the sun sets in the west, the moon rises in the east; their convergence creates the new moon (Heshuo), and the alternation of cold and heat completes the cyclical rhythm—all representing the state of "Jiji" (Completion). Yet when Kan and Li reach their extremes (Kan above, Li below), they return to their origins, meaning "Weiji" (Incompletion) is concealed within the pinnacle of "Jiji."

Zhang Heng observed that the sun embodies the essence of Yang Qi, taking form as a three-legged golden crow (the three toes symbolizing the odd-numbered Yang principle), resembling a rooster at You hour (5-7 PM), which is Yin within Yang. The moon embodies the essence of Yin Qi, taking form as a rabbit (an even-numbered creature associated with Mao), representing Yang within Yin. Du Yu further noted that the sun's intrinsic nature is red, while the moon's is white. The Yuanming Bao records that the sun symbolizes the sovereign—when the ruler governs with Dao, its radiance brightens, and the appearance of five-colored auspicious light heralds an era of peace and prosperity.

Shao Yong (Master Shao) observed that in summer, the sun moves northward following the Big Dipper, while in winter it shifts southward. At the summer solstice, the sun reaches its northernmost point (the Well constellation) before reversing southward, as Yin Qi gradually strengthens and all things begin to wither. At the winter solstice, the sun reaches its southernmost point (the Ox constellation) before turning northward, with Yang Qi growing and life renewing. The Tai Xuan Jing further explains: when the Big Dipper points north (Hai position), all things withdraw; when it points south (Si position), all things flourish. The sun's path in spring travels westward through seven constellations before turning south (rightward motion), while in autumn it moves eastward through seven constellations before turning north (leftward rotation). Meanwhile, the Big Dipper follows celestial patterns in a leftward rotation, pointing eastward through three celestial markers in spring. Together, these astronomical phenomena form the cosmic rhythm of Yin-Yang's waxing and waning.

This passage elucidates the correspondence between the movement of the Big Dipper in ancient astronomy and the transformations of Yin-Yang. At the winter solstice, the handle of the Dipper points north (Zi position), when Yang qi begins to sprout but has not yet reached its zenith—akin to a seed's initial germination. The celestial Dao moves leftward, and the Dipper's handle follows this motion. Although the sun actually moves rightward, its monthly conjunction with the moon still aligns with the Dipper's position. This period corresponds to 41 hexagrams in the Taixuan Jing (Classic of Supreme Mystery), predominantly odd-numbered, spanning 182.5 days. Here Yang qi circulates through Yang numbers, gradually filling until forming the Qian hexagram (symbolizing Heaven), when all beings begin to flourish.

At the summer solstice, the Dipper's handle points south (Wu position), as Yang qi peaks and then declines—like fruit ripening before withering. The celestial Dao rotates rightward, and the handle follows. This phase corresponds to another 40 hexagrams in the Taixuan Jing, mainly even-numbered, also lasting 182 days. Yin qi circulates through Yin numbers, gradually contracting until forming the Kun hexagram (symbolizing Earth), when all beings enter a state of storage.

The north-south axis represents the fixed orientations (Jing) of Yin-Yang, while the east-west axis serves as their circulating pathways (Wei). The sun's daily motion creates day and night; its annual journey forms the north-south oscillation, mirroring the life-death cycle of all things—when Yang qi arrives, life emerges; when it departs, death follows. The text also mentions ancient calendrical calculations: 364.5 days plus two special intervals ("Qi □ two Zan") complete 365.25 days, matching a tropical year.

Finally, it cites Han dynasty scholar Liu Zhao's record of solar positions: winter in the northern celestial sphere (Bei Lu), spring in the western (Xi Lu), summer in the southern (Nan Lu), and autumn in the eastern (Dong Lu). However, the author notes potential confusion, as Sui dynasty documents place spring in Dong Lu and autumn in Xi Lu, requiring further verification. The north-south axis (Zi-Wu meridian) serves as the fundamental reference—at winter solstice, the nascent Yang qi embodies the profound mysteries of celestial-terrestrial operations.

This passage explains the ancient astronomical patterns governing the movements of celestial bodies and their correspondence with seasonal changes.

The sun, moon, and stars follow fixed celestial patterns: when the sun moves through northern regions it creates winter, while its southern course brings summer—these directional-seasonal correspondences remain constant. The heavenly bodies rotate counterclockwise from north to east (zuoxuan) to generate all things, while the sun's clockwise movement from north to west (youzhuan) forms the latitudinal courses.

Specifically: In the first month (Mengchun, beginning of spring), the sun resides in the Lunar Lodge "Encampment" (northern constellation), corresponding to the Yin month meeting the Hai palace. The second month (Zhongchun, mid-spring) finds the sun in "Stride" (western constellation) during the Mao month conjoining the Xu palace. The third month (Jichun, late spring) positions the sun in "Stomach" constellation during the Chen month meeting the You palace. Since the sun moves westward to eastward, this is called "the sun traversing the western course"—marking spring.

By the fourth month, the Si and Shen palaces converge at the "Actual Depth" constellation as the sun moves southward, when yin qi begins to grow. The celestial Dao moves south-to-north, completing creation through clockwise rotation, while the sun forms latitudinal courses via eastward leftward movement. The seventh month (Mengqiu, early autumn) sees the sun in "Wings" constellation with Shen-Si convergence called "Quail's Tail"; the eighth month (Zhongqiu, mid-autumn) places it in "Horn" constellation during You-Chen convergence termed "Longevity Star"; the ninth month (Jiqiu, late autumn) positions it in "Chamber" constellation as Xu-Mao converge as "Great Fire." Here the sun moves east-to-west, termed "the sun traversing the eastern course"—marking autumn.

The text deliberately associates the east with autumn rather than spring, and the west with spring instead of autumn, demonstrating how north-south meridians remain immutable while east-west parallels can mutually complement. The yang sun governs daytime, moving southward from east to midnight, lengthening days as growing yang brings warmth and heat; yin governs night, moving northward from summer solstice noon, shortening days as flourishing yin brings cold and coolness.

At winter solstice the sun reaches its southernmost point with longest shadows; summer solstice finds it northernmost with shortest shadows. Should the sun fail to reach these extremes, climatic abnormalities occur: insufficient southern winter solstice brings excessive warmth, while inadequate northern summer solstice causes extreme cold.

Shao Yong (Northern Song Neo-Confucian scholar) observed: Heaven's rotation creates day and night, while the sun's course generates cold and heat. Summer's yang remains shallow, winter's yin runs deep—this results from heaven-earth interactions. Heaven completes one daily rotation while the sun advances one degree daily, rising from Yin position at dawn and setting at Xu position in summer, ascending from Chen to setting at Shen in winter, and moving between Mao rise and You set during spring and autumn.

The rising and setting of the sun determine day and night. While it appears the sun is moving, this is actually the result of celestial motion. When the sun is below the horizon, the weather is cold; when at its zenith, it becomes hot. In winter, the sun travels through the northern celestial region (Northern Path), bringing cold as it moves deep beneath the earth. In summer, it passes through the southern region (Southern Path), creating heat as it nears the surface. During spring and autumn, the sun crosses the western (Western Path) and eastern (Eastern Path) celestial regions respectively, resulting in moderate temperatures.

The sun's trajectory creates seasonal temperature variations: as it moves southward, it gradually rises from the earth's depths, while moving northward causes it to descend from shallower regions—this reflects the natural interaction of heaven and earth's energies. Some compare this to human posture, suggesting the south celestial pole tilts upward in summer (shallow sunlight) and downward in winter (deep sunlight), but this misunderstands the ecliptic (the sun's apparent path across the celestial sphere). In reality, the summer solstice sun reaches its zenith at the southern meridian (Wu position), while the winter solstice sun aligns with true north (Zi position)—both manifestations of celestial mechanics.

At winter solstice, the sun begins moving rightward from the Jixiu position (one of twelve ecliptic sectors), advancing one degree daily, while the celestial sphere rotates leftward, gaining ten degrees annually. After completing a sixty-year Jiazi cycle, the sun meets the Big Dipper—this is celestial rhythm. Winter solstice nights equal summer solstice days in length, and vice versa. Winter nights only match spring/autumn days because daylight encroaches on darkness by approximately five ke (ancient time units, ~15 minutes each). Sunrise and sunset follow fixed patterns, yet dawn arrives two-and-a-half ke before sunrise, and dusk lingers two-and-a-half ke after sunset.

The sun's apparent east-west movement follows the celestial sphere's rotation, while its summer-north/winter-south shift results from heavenly intersections. Each celestial rotation overshoots one lunar mansion, synchronizing with solar motion. The four seasons' cardinal positions are: spring at due west (You), summer at due south (Wu), autumn at due east (Mao), and winter at due north (Zi). At winter solstice's Zi hour (midnight), the sun begins rightward motion from Jixiu while the celestial sphere shifts left—thus the sun remains at Zi position, creating the illusion of "eastward sunrise, westward sunset." This is actually celestial rotation, not solar movement. In summer the sun trends northward; in winter southward: nearest the north celestial pole at summer solstice, casting shortest shadows with longest days; farthest at winter solstice, producing longest shadows and shortest days. The sun advances one degree daily while the celestial sphere gains one degree annually (matching lunar mansion intervals)—this is the resonant order of heaven and earth.

This passage describes the ancient astronomical method of determining seasonal changes and Yin-Yang balance through gnomon measurements (using an eight-foot pole to observe shadow lengths).

At the winter solstice, the sun reaches its southernmost position near the Ox constellation (牵牛), casting the longest shadow (13 feet). At the summer solstice, it reaches its northernmost position near the Well constellation (东井), producing the shortest shadow (1.5 feet). During the spring and autumn equinoxes, the sun aligns with the Lou (娄) and Horn (角) constellations respectively, resulting in equal day and night lengths and moderate shadows (7.5 feet). These shifting celestial positions form the sun’s "central path" (日行中道) in its annual motion.

The ancients observed that when the sun approaches the North Pole (summer solstice), shadows shorten while days lengthen; when it moves farther away (winter solstice), shadows lengthen while days shorten. By precisely measuring shadow lengths, they could verify whether solar terms arrived on schedule. If the shadows matched expected standards, it indicated harmonious seasonal transitions; deviations signaled unfavorable conditions for the year.

The text also notes that abnormally long shadows (excessive Yin qi) foretold floods, while unusually short shadows (excessive Yang qi) predicted droughts. A sudden shadow increase of 1.2 feet might herald a lunar eclipse. These observations were even used to assess governance—proper rule correlated with balanced celestial phenomena, while political disorder manifested in astronomical anomalies.

(Note: Ox, Well, Lou, and Horn are names from the ancient twenty-eight lunar mansions; the "gnomon" (表) was a pole for shadow measurement; "晷" refers to shadow length.)

This passage explains the ancient method of calculating solar terms by observing the changing lengths of sun shadows (gnomon measurements). When the solar shadow recedes by one chi and two cun, a complete eclipse cycle is achieved, with ten as its numerical base. The advancement of the shadow signifies the growth of Yang Qi (expansion), while its recession indicates the waning of Yang Qi (contraction). By observing these shadow variations, one can determine the arrival of solar terms.

The sages, by studying the movements of the sun and moon, correlated them with the trigrams Kan (representing water) and Li (representing fire) from the Bagua (Eight Trigrams), thereby revealing the deeper meanings of the trigrams. The Yijing (Book of Changes) states that the brightest phenomena suspended in the heavens are none other than the sun and moon. Zhu Xi explains that this resembles the Najia method (a divination technique matching the Heavenly Stems and Earthly Branches with the trigrams), where Kan corresponds to Wu and Li corresponds to Ji. The first line of the Qian (Heaven) trigram belongs to Wu, while the first line of the Kun (Earth) trigram belongs to Ji. Only by retaining Wu and returning to Ji can the Kan and Li trigrams be formed. This is because Qian and Kun are the supreme parent trigrams, while Kan and Li are the secondary parent trigrams.

The Han dynasty scholar Yu Fan said: The sun and moon suspended in the sky form the symbolic imagery of the Bagua. At the beginning of the lunar month, the moon is obscure like the Kan trigram (flowing water), corresponding to Wu; at noon, the sun resembles the Li trigram (flame), corresponding to Ji. Wu and Ji represent the central earth position, and the alternating movements of the sun and moon generate illumination. The interaction of the Qian and Kun trigrams produces Kan and Li, through which the sun and moon manifest. On the third day of the month, the moon appears like the Zhen trigram in the direction of Geng; on the eighth day, it resembles the Dui trigram in the direction of Ding; on the fifteenth day, the full moon is like the Qian trigram, fully present in the directions of Jia and Ren; by the sixteenth day, it begins to wane like the Xun trigram in the direction of Xin; on the twenty-third day, it diminishes like the Gen trigram in the direction of Bing; and by the thirtieth day, it completely vanishes like the Kun trigram in the direction of Yi. In summary, Kan and Li represent the sun and moon: the initial light of the moon emerges from Zhen, its waning form appears from Xun, the first quarter moon is seen in Dui, the last quarter in Gen, the full moon in Qian, and its disappearance in Kun. The ten-day cycle from Jia to Gui is also fully reflected within the Bagua.

The Liji (Book of Rites) records that the sun rises in the east, while the moon emerges in the west. The Shijing (Book of Songs) similarly mentions "the sun in the east" and "the moon in the east." The moon first appears in the west but reaches its zenith in the east. Although the sun rises in the east, before dawn it is already moving beneath the earth, just not yet visible above the horizon. Ancient scholars explain that the character for "sun" (日) signifies fullness, while "moon" (月) signifies deficiency, because the sun's movement is eternally constant, whereas the moon undergoes phases of waxing and waning.

The greatest awakening of heaven and earth occurs in summer (the Wu hour), and the human spirit resides in the heart. At noon, the sun follows the heavens to the south; at midnight, it moves to the north—this is the daily cycle of awakening and rest. In summer, the sun is at the Wu position, while in winter, it is at the Zi position—this is the yearly cycle of awakening and rest. Thus, summer is called "the Vast Heaven," and the Li trigram (symbolizing fire and the sun) represents the flourishing of all things.

This scripture primarily elucidates the relationship between the celestial Yin-Yang, the movements of the sun and moon, and the human body's Jing (essence) and Qi (vital energy).

When the sun (the Shen/spirit of heaven) moves across the sky during the day, human mental activity is primarily centered in the heart (associated with summer). When the sun sets at night, the Shen withdraws into the kidneys (associated with winter). By day, the spirit engages with the external world; by night, it returns inward. The phrase "storing the heart in the abyss" refers to settling the heart-mind in the Qihai (Dantian, the energy center) to nurture and preserve the Shen.

From the perspective of celestial movement, at the summer solstice, the sun occupies seven parts of the sky, while at the winter solstice, it occupies seven parts beneath the earth. Overall, the sun spends seven-tenths of its time above the earth and three-tenths below, which is why the Yang number (seven) is abundant. The sun’s path shifts between north and south, differing from the constant motion of heaven.

At night, when the sun descends into the earth, it resembles winter’s state of withdrawal and storage. At midnight (the Zi hour) during the winter solstice, the Yang Qi of heaven and the Yin Qi of earth converge in the "Yellow Spring Palace" (the deep subterranean realm), generating the vitality of all things. Just as the union of male and female Jing produces life, the merging of the sun’s Yang Qi with earthly Qi gives rise to all beings. The sun represents the Yang Hun (luminous spirit) of heaven, while the moon embodies the Yin Po (shadowy form) of earth—each balancing the other.

Zhu Xi remarked that the sun and moon rise from water and return to water. When questioned about the "Huntian Theory" (an ancient cosmological model), he explained that beyond heaven, it is not entirely water but rather Qi, while below the earth lies water. This aligns with Mencius’ statement that water flows within the earth and Su Shi’s observation that water permeates the earth’s depths. Thus, the subterranean realm is filled with water, while the space beyond heaven consists of clear and vigorous primordial Qi. Each night, the sun completes a full circuit beneath the earth—generating water to nourish all things while also evaporating excess moisture to prevent disasters. The rising of vapor to form clouds and rain is the natural circulation of heaven and earth’s dual Yin-Yang Qi.

This passage explores the interaction between water and fire (the sun) within the Yin-Yang and Five Phases framework, along with astronomical concepts of the ecliptic and celestial equator.

When water overflows without solar evaporation, catastrophic floods occur. Historical records mention ten suns appearing simultaneously during Emperor Yao's reign (though likely mythical), yet heaven's compassion for human suffering reflects this natural balancing of Yin-Yang. The sun, belonging to fire, maintains constant brightness, while the moon, associated with water, displays waxing and waning phases. Tidal phenomena provide clear evidence—the moon's movement governs ocean tides.

The Yijing (Book of Changes) describes the Mingyi hexagram ("brightness entering earth") as representing the sun's subterranean passage. Daoist cosmology holds that "heaven first generated water" (天一生水), with the sun as Yang and water as Yin. At sunrise, Yin qi dissipates; when the sun moves underground, water vapor recedes—creating day-night cycles. Cosmic operation never ceases its Yang-brightness (Yangming) activity. The Sui Shu·Astronomy Treatise similarly records the sun's water-evaporating quality.

Regarding celestial motion, ancient astronomers observed the ecliptic and celestial equator (Shen Kuo argued these weren't physical but calendrical reference lines). The celestial sphere resembles two inverted bowls: the celestial equator encircles its midline like a bowl's rim, with northern stars as the upper bowl and southern stars as the base. The ecliptic resembles the seam where two bowls join, crossing the celestial equator like a box's central crease. These two paths intersect at east-west nodes, dividing the sky into measured degrees.

When ecliptic and equator form a cross (called hui "conjunction"), solar eclipses may occur during sun-moon meetings. Lunar eclipses happen during opposition (e.g., moon at northern zi position, sun at southern wu position). New moon (shuo) solar eclipses occur when the moon blocks the sun; full moon (wang) lunar eclipses manifest Yin qi daring to confront Yang qi.

The path of the sun's movement is called the "Yellow Path" (the apparent path of the sun on the celestial sphere), also known as the "Central Path." The central positions of Wu and Ji correspond to Earth in the Five Phases (Wood, Fire, Earth, Metal, Water). The stars shift their positions with the changing seasons: westward in spring, eastward in autumn, northward in summer, and southward in winter. The sun, however, moves in the opposite direction: eastward in spring, westward in autumn, southward in summer, and northward in winter. During the transitional months of Chen, Xu, Chou, and Wei (the third, sixth, ninth, and twelfth months of the lunar calendar), which all belong to Earth, the stars also return to their proper positions along the Yellow Path.

The ancient scholar Zheng Xuan, in his commentary on the Hong Fan, noted that the intervals between the four seasons correspond precisely to the Yellow Path. Specifically, the transitional periods between winter and spring, spring and summer, summer and autumn, and autumn and winter—each lasting eighteen days and collectively totaling seventy-two days—are governed by Earth. These intervals lie at the junctions of Fire (summer) and Metal (autumn), among other elements, and spatially correspond to the Kun trigram (southwest). The Yellow Path, occupying the center, is also called the Central Path. Together with the green, red, white, and black paths, it forms an eightfold division, with the center making nine regions, assisting the sun in nurturing all things.

The Treatise on Astronomy records that the moon follows nine paths: two black paths north of the Yellow Path, two red paths south of it, two white paths west of it, and two green paths east of it, totaling nine when including the central Yellow Path. During the beginning of spring and the spring equinox, the moon travels along the eastern green path; during the beginning of autumn and the autumn equinox, along the western white path; during the beginning of winter, along the northern black path; and during the beginning of summer and the summer solstice, along the southern red path. The Yellow Path represents the harmonious and upright Qi, while the green and red paths belong to Yang, and the white and black paths to Yin. If the moon deviates from its path, traveling along a Yang path causes drought and wind, while traveling along a Yin path brings excessive rain. Thus, the Star Compendium states: When a sage ruler reigns, the sun, moon, and five planets all follow the Yellow Path. Though the moon may stray onto other paths, it never strays far from the Yellow Path.

The sun always moves along the central Yellow Path. Its inner side (north) runs from the Kui constellation to the Zhen constellation (roughly northwest to southeast), while its outer side (south) runs from the Jiao and Kang constellations to the Shi and Bi constellations (roughly northeast to southwest). The region of the eastern Jiao constellation is the Celestial Gate, and the region of the Fang constellation is the Celestial Street. The Yellow Path passes through these, forming the common pathway for the sun, moon, and five planets (the Seven Luminaries).

Shao Yong, a Northern Song Neo-Confucian scholar, explained that solar and lunar eclipses result from the intersecting cycles of the sun and moon. A lunar eclipse occurs when the sun directly opposes the moon, and a solar eclipse occurs when the moon obscures the sun—much like the mutual overcoming of water and fire in the Five Phases. Thus, the wise ruler understands and harnesses these patterns, while ordinary people merely experience them as natural phenomena.

This passage explains the correspondence between celestial movements of the sun and moon with human governance. When the sun and moon face each other, it's called "wang" (full moon), while their conjunction is termed "hui" (new moon). Solar eclipses occur during "shuo" days (the first day of the lunar month), when the moon is closest to the sun.

The sun losing its brilliance during "hui" days symbolizes how factions of petty men most easily endanger the ruler. Lunar eclipses during "wang" days resemble petty men gaining temporary dominance, though they ultimately self-destruct—just as water overcomes fire but requires containment, analogous to how noble men use wisdom to overcome petty men. The sun and moon meet twelve times annually, creating twelve full moons, with eclipses occurring when their orbits intersect.

The sun follows the ecliptic while the moon traverses nine orbital paths. Sometimes their paths cross without eclipses: during "shuo" when they share celestial longitude but the moon's orbit deviates north or south from the sun's position, or when the sun occupies the inner orbital position while the moon remains outside.

Zhu Xi observed that while both solar and lunar eclipses are irregular phenomena, lunar eclipses occur more frequently because yin (moon) obscuring yang (sun) violates cosmic principles—hence the Spring and Autumn Annals recorded only solar eclipses. The twelve annual conjunctions between sun and moon create "hui" (complete darkness of the new moon), with light reappearing at "shuo." Fifteen days after "shuo" until fifteen days before the next "hui," their opposition creates the full moon "wang."

If during "wang" they share the same orbital path, the sun overpowering the moon causes lunar eclipses; if during "shuo" they share both longitude and orbit, the moon obscuring the sun creates solar eclipses. Though these follow natural laws, when rulers cultivate virtue and appoint worthy officials—creating abundant yang energy that repels yin influence—eclipses that should occur might not manifest. Conversely, during political decay with treacherous ministers, petty men's ascendancy, or foreign invasions (signifying yin overpowering yang), predicted eclipses will invariably occur as celestial anomalies. The Guliang Commentary documents four types of solar eclipses, including the notable cases of Duke Yin's third year "hui eclipse" and the subsequent "shuo eclipse."

This scripture primarily explains the ancient astronomical observations of solar and lunar eclipses, detailing their formation principles and symbolic significance.

Regarding solar eclipses: When the moon moves between the sun and earth, completely blocking sunlight, it is called "the completion of a solar eclipse" (ri you shi zhi ji). Ancient observers noted that solar eclipses mostly occurred during daytime, though "nocturnal eclipses" (ye shi) could also occur when the sun was below the horizon, making the obscured sun invisible to observers. Nocturnal eclipses typically happened at month's end (hui ri), when starlight also appeared dimmer.

The text cites the solar eclipse recorded in the Book of Songs during the sixth year of King You of Zhou (776 BCE) - China's earliest precisely dated eclipse record. Ancient calendrical astronomy (as in the Zhou Bi Suan Jing) held that the sun travels 1 degree daily while the moon covers 13⁷⁄₁₉ degrees, with the moon catching up to the sun after approximately 29.5 days to form "conjunction" (jiao hui, i.e., new moon). Eclipses only occurred when the moon intersected the sun's path (near the lunar nodes).

Ancient people interpreted solar eclipses as celestial phenomena of "yin encroaching upon yang," symbolizing ministers usurping their ruler. This was explained through heavenly stems and earthly branches: the ten heavenly stems (jia to gui) represented yang-aligned nobility, while branches like hai and chou symbolized yin-aligned subjects. For instance, when an eclipse occurred on xin day (associated with metal) which should theoretically control mao (wood), it portended ministerial rebellion. Such celestial signs served as warnings about ruler-subject relations.

The text concludes by noting that eclipses follow no fixed schedule, though ancient calendars calculated their recurrence in roughly 173-day cycles. Because the moon's path (the white path) intersects the sun's ecliptic (the yellow path) at an angle, eclipses only occur near these intersecting nodes. When the moon orbits closer to earth (perigee), solar eclipses occur more readily, whereas distant orbits (apogee) make them less likely. These understandings reflect the observational achievements of ancient Chinese astronomy.

This passage primarily discusses the astronomical phenomena of solar and lunar eclipses and their symbolic significance, along with the ancient ritual protocols for responding to these events. The text notes that while eclipses follow certain cyclical patterns, their exact timing is not fixed and they are not confined to specific solar terms like the equinoxes or solstices. The ancients regarded eclipses as abnormal celestial occurrences, particularly solar eclipses where the bright sun is suddenly obscured, turning day into night—an extremely ominous phenomenon.

When ancient rulers encountered solar eclipses, they would implement a series of ritual responses: beating drums, offering coin sacrifices, reducing meals, suspending music, and other measures to demonstrate reverence for celestial anomalies and to warn the sovereign. The Dao of Heaven is profound and inscrutable; at times these celestial phenomena indeed correspond to human fortunes and misfortunes. Thus, sages utilized these anomalies to admonish humanity. The wise comprehend their deeper meaning, while ordinary people would heed the omens of fortune and misfortune to cultivate self-awareness. However, divine signs can only assist in moral instruction—they should not be wholly relied upon, and discourse about the divine must be measured.

Du Yu explains that lunar eclipses occur when the full moon is obscured from sunlight, while solar eclipses result from the moon blocking the sun. The text cites the Spring and Autumn Annals to illustrate how Confucius recorded solar eclipses and celestial changes over 242 years but omitted lunar eclipses, as the moon symbolizes feudal lords and foreign tribes—its changes do not affect the stability of the Central States' governance.

The concluding section references commentaries by Zuo Qiuming and Jin Dynasty scholar Du Yu, dividing the day into ten periods, each corresponding to different social classes: midday represents the ruler; breakfast time corresponds to dukes; dawn to high ministers; cockcrow to scholar-officials; midnight to commoners; the hour of human rest (evening) to charioteers; dusk to minor functionaries; sunset to subordinate officials; afternoon to servants; and late afternoon to low-ranking clerks. The periods of sunrise and late morning (禺中, 9-11 AM) are left unassigned to show reverence for royalty. Here, 禺中 corresponds to the Si hour (9-11 AM), while sunrise aligns with the Mao hour (5-7 AM).

This passage elucidates the significant position of the Li hexagram (symbolizing the sun and brightness) in the Book of Changes (Yijing) and its philosophical relationship with Yin-Yang principles.

The Yijing is a classic that venerates Yang qi (vital energy) while restraining Yin qi. The sun symbolizes the sovereign ruler and is thus highly revered. The first thirty hexagrams of the "Upper Classic" conclude with Li, representing the celestial sun upon which all things depend for illumination. The latter thirty-four hexagrams of the "Lower Classic" end with Jiji and Weiji, which also incorporate Li's imagery, as people's livelihoods rely on the sun's radiance. The Qian hexagram (symbolizing the sovereign) interacts with Kun to form Li, embodying the principle of ministers' loyalty to their ruler.

When Li ascends to heaven, it becomes Dayou (signifying widespread illumination); conversely, descending creates Tongren (indicating light shining downward). Li appearing above the earth forms Jin (symbolizing sunrise), while its absence results in Mingyi (representing the sun's concealment). These transformations reflect the philosophy of exalting Yang qi and the concern that brightness might fail to rise to the heavens.

Li's imagery disperses throughout other hexagrams with distinct functions: Ding represents cooking, Bi symbolizes cultural cultivation, Feng embodies the midday sun, and Ge signifies calendar creation. Conversely, Kui, Shike, and Lü present Li's inverse states.

The sun, paradoxically termed "Great Yin" (Taiyin), constitutes the origin of all things. Even the moon and stars borrow the sun's radiance—how much more do other creatures depend on it? When King Wen of Zhou was imprisoned at Youli during his "Mingyi" (damaged brightness) misfortune, he developed the Zhouyi and initiated Confucius' "Ten Wings" tradition. Confucius' continuation of King Wen's work resembles the sun's orderly alternation between day and night—a truly fortunate legacy for later generations.

(Note: The "Ten Wings" refer to the Yizhuan, ten commentaries explaining the Yijing; Youli was King Wen's prison under King Zhou of Shang.)