the Luo Writing

古來聖師，大慈大悲，以抱一無為之道，留於後世，蓋欲人人成道，個個了真耳。一者，先天真一之氣，即陰陽混合不二之氣，即性命凝結不散之氣。此氣在人身中，四大不著，五行不到，無形無象，至虛至靈，活活潑潑的，號日谷神。此神主宰萬象，掌握陰陽，所云谷神不死，是謂元牝。元牝之門，是謂天地根心。

Since ancient times, the great sages have shown boundless compassion, leaving the principle of "holding on to unity and non-action" for future generations, with the sole intention that everyone can attain the Dao and each person can realize their true nature. The term "one" refers to the primordial true energy of the Earlier Heaven, which is the energy where yin and yang are blended into one, not divided into two. It is the energy where life and destiny are united and not scattered. This energy exists within the human body, not grasped by the four elements of earth, water, fire, and wind, nor can the Five Phases reach it. It is formless and without appearance, extremely empty yet extremely vital, lively and active, and is called "the spirit of the valley." This spirit governs all phenomena and controls yin and yang. It is the fundamental heart of the universe as mentioned in the "Book of Dao and Virtue" where it says, "The spirit of the valley does not die; this is called the primordial female. The gate of the primordial female is called the root of heaven and earth."

抱者，持守也。抱一者，即持守此一氣，綿綿常存而不失，所云守黃庭、養谷神也。但抱一非空空無為之說，乃逆退先天真陽，不為後天假陰所傷也。逆退真陽，自有真陰溫養，真陰真陽相會，健順合，元牝交，動不離靜，靜不離動，自有天然真火，爐中赫赫長紅，先天漸凝，後天漸化，谷神堅固，即成無漏真人。

"Embracing" means to hold on. So "embracing oneness" means to hold onto this energy continuously without losing it, which is what the alchemists call "guarding the Yellow Court and nurturing the grain spirit." However, embracing oneness is not just sitting in stillness doing nothing; it is to reverse and draw back the "Earlier Heaven True Yang" (the pure original yang energy that has not been tainted), preventing the "Later Heaven False Yin" (the turbid yin energy that arises after birth) from harming it. When the true yang is drawn back in reverse, the "true yin" (the pure quiet yin of Earlier Heaven) naturally comes to nurture it. The union of true yin and true yang, the harmonious combination of strength and gentleness, the meeting of the primordial male and female principles, movement without losing stillness, and stillness without losing movement, naturally leads to a natural true fire burning brightly in the alchemical furnace. The qi of Earlier Heaven gradually condenses, the qi of Later Heaven gradually dissipates, the grain spirit becomes firm and unshakable, and thus becomes a true person without any leakage.

所謂要得谷神長不死，須憑元牝立根基。真精既返黃金屋，一顆靈光永不離也。真精、靈光，皆谷神之別名。靈光不離，即谷神不死，谷神不死，則得長生矣。

The Dan Jing says: In order for the spirit essence to remain eternal and not die, one must establish a foundation through the gate of the original yin and yang. Once the true essence has returned to the golden chamber (the dan field), the luminous light will forever remain undivided. This is exactly what is being discussed. "True essence" and "luminous light" are both alternative names for the spirit essence. When the luminous light does not disperse, the spirit essence does not die; when the spirit essence does not die, one attains longevity.

是谷也，在圓圖，則乾坤中虛處是；在方圖，則十字中分處是；在人身，則四象和合處是。是神也，在圓圖，則乾坤交代處是；在方圖，則十字交接處是；在人身，則四象動靜處是。有谷則神存，失谷則神亡，生之在此，死之在此，陰生在此，陽長在此，古人號曰生門、死戶，又曰造化爐、陰陽戶。儒曰道義之門，釋曰不二法門，道曰眾妙之門。總而言之曰這個而已。

This "valley" corresponds to the empty space between the Trigrams 乾 (Heaven) and 坤 (Earth) in the circular diagram, and to the central cross point in the square diagram. In the human body, it is where the four elements harmonize. This "spirit" corresponds to the junction where 乾 and 坤 meet and change in the circular diagram, to the intersection of the cross in the square diagram, and in the human body, it is where the dynamic and static aspects of the four elements are in motion. When there is a valley, the spirit exists; when the valley is lost, the spirit perishes. Birth occurs here, death occurs here, yin is born here, and yang grows here. The ancients called it the "gate of life" and "gate of death," also the "furnace of creation" and "gate of yin and yang." Confucianism calls it the "gate of morality and righteousness," Buddhism calls it the "gate beyond duality," and Taoism calls it the "gate of all wonders." In summary, it is simply called "this."

若有上智者得遇明師，指示這個端的，逆而修之，聖胎現成，不使陽極生陰，直登彼岸，再加向上工夫，煉神還虛，逆於父母未生以前面目，打破虛空，跳出陰陽之外，聖而不可知之之謂神矣。噫！順去死，逆去活，往往教君尋不著，不遇真師，逆之一宇，豈易知哉！

If a person of superior wisdom meets a true master who points out the true origin of "this," he can reverse the process and naturally form a holy embryo. This prevents yang from reaching its extreme and giving rise to yin, allowing him to directly cross over to the other shore. Adding another level of upward cultivation, "refining the spirit back to emptiness," he reverses back to his original nature before his parents gave birth to him, breaking through the void and stepping beyond yin and yang. This is called "the saint's attainment is so profound it is beyond comprehension, which is called the divine." Alas! Following the natural path leads to death, while reversing the process leads to life. This saying often leaves one unable to find the right path. Without encountering a true master, how can one easily understand the concept of "reversal"?

文王索生八卦圖，文王後天八卦方位，後天順行造化圖，後天逆運變化圖，金木交併圖，坎離顛倒圖，乾坤顛倒圖，解脫本面。

This section presents eight diagrams: "King Wen's Diagram of the Eight Trigrams Originating from Parents," which depicts the trigrams Qian and Kun (Heaven and Earth) seeking each other to produce six child trigrams; "Later Heaven Positioning of the Eight Trigrams," which shows the arrangement of the Later Heaven trigrams; "Diagram of the Orderly Progression in Later Heaven," which illustrates the process of yin and yang transformation leading to birth, aging, illness, and death; "Diagram of the Reverse Transformation in Later Heaven," which depicts the gradual return to the Earlier Heaven through reverse cultivation within the Later Heaven; "Diagram of Metal and Wood Interacting," which portrays the union of the trigram Dui (Metal) and Zhen (Wood), harmonizing their nature; "Diagram of Inverting Kan and Li," which illustrates the practice of drawing yang from Kan and filling yin into Li; "Diagram of Reverting Qian and Kun," which depicts the restoration of Qian and Kun to their original positions, with the qualities of strength and gentleness returning to their source; "Diagram of Liberation," which portrays the final state of freeing oneself from all constraints and revealing one's true nature.

文王後天八卦，仍是羲皇所畫之卦，不過於已成卦中，看出有此一番道理，故變其卦之義，卦之氣，發羲皇未發，非強作也。如乾為老陽，乃諸陽之宗，為父。坤為老陰，乃群陰之主，為母。

King Wen's Later Heaven Trigrams still use the same eight trigrams drawn by Fuxi, but after they were already drawn, a deeper meaning was discovered within them. Therefore, the meanings and energies of the trigrams were changed, bringing out aspects that Fuxi did not fully develop. This was not forced or artificial. For example, Qian is the old yang, the master of all yang, hence it is regarded as the father; Kun is the old yin, the master of all yin, hence it is regarded as the mother.

父母相配，陰陽相交，必生男女，故乾一索坤，得坤之初爻而生巽，為長女；坤一索乾，得乾之初爻而生震，為長男。乾再索坤，得坤之中爻而生離，為中女；坤再索乾，得乾之中爻而生坎，為中男。乾三索坤，得坤之上爻生兌，為少女；坤三索乾，得乾之上爻而生艮，為少男。

The parents are compatible, and yin and yang interact, inevitably producing children. Therefore, the Trigram Qian first seeks the Trigram Kun, obtaining the first line (a yin line) from Kun to produce the Trigram Xun, which represents the eldest daughter. The Trigram Kun first seeks the Trigram Qian, obtaining the first line (a yang line) from Qian to produce the Trigram Zhen, which represents the eldest son. The Trigram Qian seeks the Trigram Kun again, obtaining the middle line from Kun to produce the Trigram Li, which represents the middle daughter. The Trigram Kun seeks the Trigram Qian again, obtaining the middle line from Qian to produce the Trigram Kan, which represents the middle son. The Trigram Qian seeks the Trigram Kun once more, obtaining the top line from Kun to produce the Trigram Dui, which represents the young daughter. The Trigram Kun seeks the Trigram Qian once more, obtaining the top line from Qian to produce the Trigram Gen, which represents the young son.

乾索坤之三陰，陽變為陰而生三女；坤索乾之三陽，陰變為陽而生三男。男女既生，於是男從父而女從母，乾統三男，居於東北；坤統三女，居於西南。乾老父三陽真氣，為三男所得，健德收斂，故得藏於西北寒盛之方；坤老母三陰真氣，為三女所得，順性失常，故遷於西南殺機之鄉。

The trigram Qian seeks the trigram Kun and obtains three yin lines; the yang position turns into yin and produces three daughters. The trigram Kun seeks the trigram Qian and obtains three yang lines; the yin position turns into yang and produces three sons. Once the sons and daughters are born, the sons follow their father and the daughters follow their mother. Qian governs the three trigrams of sons and resides in the Northeast. Kun governs the three trigrams of daughters and resides in the Southwest. The three yang energies of the old father Qian are divided by the three sons, so its strong and vigorous virtue becomes concealed and not apparent, thus it retreats to the Northwest, the place with the strongest cold. The three yin energies of the old mother Kun are divided by the three daughters, so its gentle and yielding nature loses its regularity, thus it moves to the Southwest, the place where the severe and sharp season occurs.

離得坤之中陰，陰麗陽中，陰借陽而生明，故居正南火旺之方。坎得乾之中陽，陽陷陰中，陽入陰而生潮，故居正北水旺之方。

The Trigram Li obtained the central yao of the Trigram Kun, with the yin line attached between two yang lines. Yin relies on yang to generate brightness, hence it resides in the direction of Due South where the fire energy is strongest. The Trigram Kan obtained the central yao of the Trigram Qian, with the yang line sinking between two yin lines. Yang enters the yin to produce the ebb and flow of tides, hence it resides in the direction of Due North where the water energy is strongest.

震得乾之初陽，初陽主生長，故居正東木旺之方。兌得坤之末陰，末陰主消化，故居正西金旺之方。艮得亁之末陽，末陽主靜養，故居東北陽弱之方。巽得坤之初陰，初陰主潛進，故居東南陽盛之方。

The Trigram Zhen (Thunder) has the Yang of the first line from the Trigram Qian (Heaven), and the initial Yang governs growth and development, so it resides in the direction of Due East where the Wood energy is strongest. The Trigram Dui (Lake) has the Yin of the top line from the Trigram Kun (Earth), and the final Yin governs decline and completion, so it resides in the direction of Due West where the Metal energy is strongest. The Trigram Gen (Mountain) has the Yang of the top line from the Trigram Qian (Heaven), and the final Yang governs stillness and rest, so it resides in the Northeast where the Yang energy is weak. The Trigram Xun (Wind) has the Yin of the first line from the Trigram Kun (Earth), and the initial Yin governs concealment and gradual progress, so it resides in the Southeast where the Yang energy is strong.

乾、坎、艮、震屬陽，造生萬物；巽、離、坤、兌屬陰，化成萬物。父母男女，自相配合，以行卦氣，後天六十四卦亦於此而生。六十四卦生，造之化之，生之成之，造而又化，化而又造，生而又成，成而又生，消息盈虛，無有停息，此已生出者，故謂後天。後天者，順生之道也。而逆運之道亦在內。

The trigrams Qian, Kan, Gen, and Zhen belong to the Yang category and are responsible for creation and generating all things. The trigrams Xun, Li, Kun, and Dui belong to the Yin category and are responsible for transformation and completing all things. Parents and children combine with each other, circulating the trigram energies, and the Later Heaven's sixty-four hexagrams thus arise. Once the sixty-four hexagrams are generated, there is both creation and transformation, birth and completion: creation follows transformation, transformation follows creation; birth follows completion, completion follows birth. There is constant waxing and waning, fullness and emptiness, without ever stopping. All of these belong to the aspect of "already being born," hence it is called "Later Heaven." Later Heaven follows the path of generating all things; while the path of reversing and returning to the source is also contained within it.

離本陽而反為女者，外陽而內陰，陰居中位，真陰也。坎本陰而反為男者，外陰而內陽，陽居中位，真陽也。外陽者，後天之陽；內陰者，先天之陰；外陰者，後天之陰，內陽者，先天之陽。先天是主，後天是賓，坎離輻輳，水火相濟，寒暑有時，故足以代乾坤而行造化。

The trigram Li is originally a yang trigram, yet it is considered as female, because its outer two lines are yang and its inner line is yin. The yin in the central position is the true yin. The trigram Kan is originally a yin trigram, yet it is considered as male, because its outer two lines are yin and its inner line is yang. The yang in the central position is the true yang. The outer yang is the yang of later heaven, while the inner yin is the yin of earlier heaven; the outer yin is the yin of later heaven, while the inner yang is the yang of earlier heaven. Earlier heaven is the host, and later heaven is the guest. The trigrams Kan and Li come together, with water and fire mutually regulating each other, and the alternation of cold and heat follows a regular pattern, so they are sufficient to replace the trigrams Qian and Kun in carrying out the transformations of the universe.

震，陰多陽少，而為男者，震乃陽氣方升。陽氣升而足以破陰氣。兌，陽多陰少，而為女者，兌為陰氣外現。陰氣現而足以滅陽氣。震為生機，兌為殺機，金木相併，生殺分明，故足以代乾坤而成造化。

The Zhen hexagram has more yin lines and fewer yang lines, yet it is considered masculine, because Zhen represents the initial rising of yang energy, and once yang energy begins to rise, it is sufficient to overcome yin energy. The Dui hexagram has more yang lines and fewer yin lines, yet it is considered feminine, because Dui represents the manifestation of yin energy externally, and once yin energy appears, it is enough to eliminate yang energy. Zhen represents vitality, while Dui represents destructive power. The metal of Dui and the wood of Zhen interact, clearly distinguishing between creation and destruction, thus being able to replace Qian and Kun to accomplish the process of generation and transformation.

乾與巽交不合，坤與艮交不正。乾老陽，坤老陰，不能生育，艮僅交接巽陽，巽只順生其陰，故八卦方位，乾坤艮巽居於四隅，坎離震兌居於四正也。此後天逆順之道。聖賢盡性至命之學，亦不外此。

The trigrams Qian and Xun do not harmonize with each other, nor do Kun and Gen fit properly. Qian represents old yang, and Kun represents old yin, and they are no longer capable of producing offspring. Gen can only follow the remaining yang from Xun, while Xun itself merely follows the yin that gave it birth. Therefore, in the Later Heaven arrangement of the eight trigrams, Qian, Kun, Gen, and Xun are placed in the four corners (northwest, southwest, northeast, southeast), while Kan, Li, Zhen, and Dui are placed in the four cardinal directions (north, south, east, west). This reflects the principle of the Later Heaven trigrams having both reverse and forward arrangements. The scholarly pursuit of "exhausting the nature and attaining the destiny" by sages does not go beyond this scope.

人之本來，陰陽混成，性命一家，健順相合，純是先天，一交後天，真中有假，假陷其真，健體有虧，順體有傷，性命分為兩處，於是健德不彰，靈明而誤用，元神昧而識神出矣。順德不真，昏暗而有險，元精藏而濁精生矣。如圖坎離居中正位，乾移西北，坤遷西南也。

Human nature originally consists of yin and yang blended together as one, with "nature" (heart nature) and "destiny" (essence and qi) residing together in harmony. The virtue of Qian (Heaven), characterized by strength, and the virtue of Kun (Earth), characterized by compliance, are perfectly aligned, representing a state of pure Earlier Heaven. Once entering Later Heaven, truth becomes mixed with falsehood, and falsehood obscures truth: the essential nature of strength is diminished, and the essential nature of compliance is harmed. Nature and destiny are separated and placed in different positions. Thus, the virtue of strength no longer manifests — the inherent clarity is misused, and the Origin God (the natural awareness of Earlier Heaven) becomes obscured, giving rise to the "discriminating mind" (the calculating and discerning mind of Later Heaven). Similarly, the virtue of compliance is no longer pure — it becomes dark and concealed, with danger hidden within. The pure essence of Earlier Heaven remains hidden, while turbid essence arises. In the Later Heaven Trigrams diagram, the trigrams Kan and Li occupy the central north and south positions, while the trigram Qian is pushed to the northwest corner and the trigram Kun is moved to the southwest corner.

後天精神用事，動而暴燥，氣性發矣。和而同流，妄情起矣。如圖震居於正東卯地，陽變為陰，兌居於正西酉地，和變為殺也。精神性情變幻，陰氣潛入而進，陽氣衰弱而止，如圖巽居東南陽旺之地，艮居東北陽暗之鄉也。

In the Later Heaven arrangement, once the essence and spirit take charge, any movement leads to impatience and fierce temper, and the "temperament" (inherited blood and disposition) erupts; if one is always accommodating and follows the crowd, the "false emotions" (erroneous mental states) arise. On the diagram, the Zhen trigram occupies the Due East position of Mao, where it should be purely yang, yet it turns into yin; the Dui trigram occupies the Due West position of You, where it should be harmonious, yet it turns into severe and killing. The essence, spirit, nature, and emotions change so unpredictably that yin qi quietly invades and advances step by step, while yang qi gradually weakens and stagnates. On the diagram, the Xun trigram occupies the Southeast area where yang qi is strong, while the Gen trigram occupies the Northeast corner where yang qi is dim.

噫！後天一發，陰漸長，陽漸消，不至消盡其陽而不止。圖之乾遇巽而垢，坤逢艮而剝，離上坎下，火水不濟。震東兌西，雷澤歸妹之所由來也。是道也，天地自然順行之道，陽極必陰，陰極必死，亦人之無可如何者。但聖人又有逆運之道，善能竊陰陽、奪造化、轉乾坤、扭氣機於後天中返先天，死裡逃生，其道何在？仍不外乎後天八卦之理。

Alas! Once the Later Heaven begins to move, yin grows day by day while yang diminishes day by day, and it will not stop until the yang is completely exhausted. In the diagram, the Qian trigram meets the Xun trigram, forming the Gou hexagram— one yin quietly arising among five yangs; the Kun trigram meets the Gen trigram, forming the Bo hexagram— one yang alone remaining among five yins. The Li trigram is above and the Kan trigram is below, fire rises upward and water flows downward, they do not interact, which is the image of Wei Ji; the Zhen trigram is in the east and the Dui trigram is in the west, the young male and the young female lose their proper order, which is the origin of the Gui Mei hexagram. This is the natural way of heaven and earth moving in the order of the Later Heaven: when yang reaches its peak it must turn to yin, and when yin reaches its peak it must turn to death, which is something human power cannot change. But the sages have another method of reversing the order, skillfully seizing yin and yang, reclaiming the transformation of nature, turning heaven and earth, and shifting the vital energy. They return from the Later Heaven to the Earlier Heaven, escaping from death. But where is this path? It still cannot escape the principles of the Later Heaven trigrams.

圖之坎、離、震、兌居於四正，乾、坤、艮、巽居於四隅，此中天機，非師難知。離中一陰，人心是也；坎中一陽，道心是也。道心本是乾家中陽，因交後天，入於坤宮，陽陷陰內，健者不健矣。人心本是坤家中陰，因失先天，入於乾宮，陰竊陽位，順者不順矣。若能虛其心，則人心化。人心化，則陰順而仍還於坤火，返其真矣。若能實其腹，則道心生。道心生，陽則健而仍還於乾，水歸於源矣。

The trigrams Kan, Li, Zhen, and Dui occupy the four cardinal directions of southeast, northwest, northeast, and southwest respectively. The trigrams Qian, Kun, Gen, and Xun retreat to the four corners. The hidden wisdom here is difficult to comprehend without guidance from a true master. The central yao (line) of the Li trigram is the "human heart" — the mind of knowledge, desire, and emotion in the Later Heaven. The central yao of the Kan trigram is the "Dao heart" — the mind of innate goodness and heavenly principle in the Earlier Heaven. The Dao heart originally belonged to the central yao of the Qian trigram, but because it entered the Later Heaven, it fell into the Kun palace, where the yang was trapped within the yin. Thus, the strong and vigorous became weak. The human heart originally belonged to the central yao of the Kun trigram, but because it lost the Earlier Heaven, it entered the Qian palace, where the yin took the place of yang. Thus, the gentle and yielding became unyielding. If one can "empty the heart" — remove private desires and preconceptions from the chest, the human heart will naturally dissipate. When the human heart dissipates, the yin will return to its proper place, reverting to its original state. If one can "fill the belly" — cultivate the true vital energy within the abdomen, the Dao heart will naturally arise. When the Dao heart arises, the yang will regain its strength, returning to its original position, and the water will flow back to its source.

兌為金，他家客氣也。震為木，我家主氣也。震本陽，其中有陰；兌本陰，其中有陽。主氣為客氣所盜，東虛而西實，若於殺中求生，殺氣變而為和氣，金情戀木慈仁，金還其元矣。木性愛金順義，木返其本矣。

The Trigram Dui belongs to metal and represents the "courteous" energy, which is an external disturbance. The Trigram Zhen belongs to wood and represents the "dominant" energy, which is the inherent controlling force. Zhen is originally a yang trigram, but it contains one yin line in the middle; Dui is originally a yin trigram, but it contains one yang line in the middle. The dominant energy of one's own is taken by the external courteous energy, resulting in emptiness on the east and fullness on the west. If one can seek vitality amidst the harsh and destructive energy, the harsh energy can transform into a harmonious and pleasant one: the affection of metal is drawn to the kindness and compassion of wood, and thus metal returns to its original nature; the nature of wood is attracted to the righteousness of metal, and thus wood returns to its root.

取坎填離，健復本命，借離煉坎，順還本性，以震求兌，健動而能和順；以兌求震，和順而能健動，健順如一，乾坤相合，四象相和，五行攢簇，後天精、神、魂、魄、意歸真，五德五元，渾然圓成，還原返本，金丹有象，所謂「乾坤交媾罷，一點落黃庭」。

"Taking the Water Trigram and filling the Fire Trigram" refers to retrieving the true yang from the center line of the Water Trigram and using it to fill the deficiency in the Fire Trigram, thus restoring the original "destiny" through the re-emergence of strength and vitality. "Borrowing the Fire Trigram to refine the Water Trigram" involves using the clarity of the Fire Trigram to refine the stagnation within the Water Trigram, thereby restoring the original "nature" through the re-emergence of flexibility and gentleness. Using the Thunder Trigram to seek the Lake Trigram signifies a dynamic and vigorous action that is also harmonious and gentle. Using the Lake Trigram to seek the Thunder Trigram signifies a harmonious and gentle state that is also dynamic and vigorous. Strength and gentleness combine as one, Heaven and Earth recombine, the four trigrams harmonize with each other, the Five Phases converge to the center, and the five essences—spirit, soul, vitality, form, and will—return to their true forms. The five virtues and five elements become perfectly complete. Returning to the original state, the "Golden Elixir" takes shape, which is what the alchemical texts refer to as "Heaven and Earth have united, and a single point falls into the Yellow Court."

一點者，丹元也。黃庭者，中央也。丹落中央，陰陽一氣，還我娘生本來面目，基址堅固，所謂「一粒金丹吞入腹，始知我命不由天」。噫！健順一失，性命分離，五行錯亂。健順一復，性命凝結，五行攢簇。一失無不失，一復無不復，後天變化有為之道大矣哉！

The term "one point" refers to "Dan Yuan" — the initial seed of the golden elixir. "Huang Ting" refers to the central part of the body. When the elixir settles in the center, yin and yang combine into a single qi, restoring one's original form at birth. The foundation becomes firm, which is what the elixir scriptures say: "When a single grain of golden elixir enters the abdomen, one realizes that one's destiny is not determined by heaven." Alas! Once the qualities of strength and harmony are lost, nature and life separate, and the Five Phases become disordered. Once strength and harmony are restored, nature and life unite, and the Five Phases gather together. If one point is lost, nothing remains intact. If one point is restored, everything is recovered. This "active" way of transformation in the Later Heaven is truly remarkable!

但還原返本，乾坤相合，只完得前半工夫，還有後半工夫，猶未完的。蓋道至乾坤相合，是將後天已返成先天矣。既返成先天，從此再立鼎爐，別置鉗錘，用無為逆運之道，顛倒乾坤，乾逆退而坤順生，借陰以全陽，溫之養之，用天然真火烹煉，消盡一身後天陰濁之氣，煅成一個金剛不壞之物，從虛無中透出，入於無聲無臭之境，還我未生身以前面目，方是大解大脫，逍遙自在，無拘無束之天矣。

However, restoring the original state and harmonizing heaven and earth only completes the first half of the practice. The second half is yet to come. When one reaches the stage of harmonizing heaven and earth, it means that the later heaven has already been transformed into the earlier heaven. Once transformed into the earlier heaven, one must then establish a new cauldron and use a different set of tools, switching to the method of "non-action" (wuwei) for reverse cultivation: reversing heaven and earth, making heaven retreat and conceal in reverse, and allowing earth to develop in its natural order. Using the yin energy to preserve the yang energy, one gradually warms and nurtures the body, employing "true fire"—a natural fire that does not rely on mental force—to refine and purify the body's later heaven yin and turbid energies, transforming them into an indestructible diamond-like substance. Emerging from nothingness, one enters a state of silence and odorlessness, returning to one's original nature before birth. Only at this stage does one achieve great liberation and release, entering a realm of complete freedom and boundlessness.

先天八卦，一氣循環，渾然天理，從太極中流出，乃真體未破之事；後天八卦，分陰分陽，有善有惡，在造化中變動，乃真體已虧之事。

The Earlier Heaven Trigrams represent a continuous cycle of one qi, a unified manifestation of heavenly principles, directly flowing from the Taiji. They describe the "true essence"—the original complete and perfect nature of human life—before it has been damaged. The Later Heaven Trigrams, on the other hand, involve the separation of yin and yang, with both good and evil present, constantly changing within the process of creation and transformation. They describe the state after the true essence has already been diminished.

真體未破，是謂生出者，須當無為。無為之妙，在乎逆中行順，逆藏先天之陽，順化後天之陰，歸於父母未生以前面目，不使陰氣有傷真體也。真體有傷，是已生出者，當須有為，有為之竅，在乎順中用逆，順退後天之陰，逆返先天之陽，歸於娘生本來之面目，務使陽氣還成真體也。

The true essence that has never been damaged belongs to the category of the original heavenly vital energy that has not yet manifested, and should be cultivated through the practice of "wu wei" (non-action). The subtlety of wu wei lies in "reversing in order to follow": reversing to gather the heavenly yang energy, following to dissipate the later heaven yin energy, returning to the original form before the parents gave birth to me, and preventing the yin energy from harming the true essence. If the true essence has already been injured, it belongs to the category where the later heaven vital energy has already begun to manifest, and therefore "you wei" (active cultivation) must be used. The key to you wei lies in "following in order to reverse": following to remove the later heaven yin energy, reversing to return the heavenly yang energy, returning to the original form at the time of birth, and ensuring that the yang energy regathers to form the true essence again.

但先天未生出者，猶有分別；後天已生出者，亦有分別。當在胞胎之時，先天陰陽，五行一氣，包含無形無跡不可見。未生出者，及其生身以後，未交後天，不識不知，順帝之則，至善無惡，雖有陰陽五行之性，而無陰陽五行之質，一氣渾然，亦未生出者也。

However, among the "unmanifested" aspects of the Earlier Heaven, there are distinctions, and among the "manifested" aspects of the Later Heaven, there are also distinctions. While still in the mother's womb, the yin and yang and the Five Phases are combined into one qi, encompassing the fetus, invisible and intangible, unseen and unperceived. This is one form of the unmanifested. After birth, before entering the Later Heaven, the person is in a state of confusion and ignorance, naturally following the heavenly principle—this is what the "Great Ode" from the Book of Poetry says: "Not knowing, not recognizing, following the Mandate of Heaven." It is purely the utmost goodness with no evil, though it already possesses the "nature" of yin and yang and the Five Phases, it has not yet formed the "substance" of yin and yang and the Five Phases, remaining as a single qi, which is another form of the unmanifested.

先天逆中順行者，即逆藏先天陰陽五行，而歸於胞胎一氣之中，順化後天之陰，而保此一氣也。當生身之初，後天陰陽五行，入於軀殼之中，與先天陰陽五行相合，先天之內，即雜後天之氣。雖後天之氣未發，而形跡已露，如嬰兒善惡剛柔，本於性成，但後天為先天所統攝，性相近耳。此已生出者也。

The concept of "reversing in order to follow" mentioned in the Earlier Heaven system refers to reversing the process of collecting the yin and yang and the Five Phases of the Earlier Heaven back into the original unified qi of the embryo, while simultaneously following the process of dissolving the later heaven's yin qi, in order to preserve this unified qi. When a person is first born, the yin and yang and Five Phases of the Later Heaven enter the body, mixing with those of the Earlier Heaven. At this point, the Later Heaven's qi has not yet manifested, but its traces are already present—like the innate nature of goodness, evil, strength, and softness in an infant, which are inherent from birth. However, since the Later Heaven is still governed by the Earlier Heaven, Confucius only said "human nature is similar." This is a form of something that has already emerged.

及其先天陽極，交於後天，知識開而靈竅閉，其機已發，大肆張狂，亦已生出者也。後天順中用逆者，即順退已發之陰，歸於初生未發之處，返出先天之陽，以還此初生也。

When the yang of the Earlier Heaven reaches its peak and turns to enter the Later Heaven, the mind opens up, and the clear and bright passage closes. Once the mechanisms of the Later Heaven have begun to operate, they become excessive and unrestrained — this is another kind of emergence. The Later Heaven's concept of 'following the natural course while using the reverse' means following the path to reduce the already excessive yin energy, returning it to the state before it had begun to manifest, and then bringing back the yang energy of the Earlier Heaven to restore the original state of its beginning.

陽健陰順，復見本來面目，仍是先天後天兩而合一之原物，從此別立乾坤，再造鼎爐，行先天逆中用順之道，即為九還七返大還丹矣。今以先天圖，移於後天圖內者，使知真體未破者，行無為自然之道，以道全形，逆中行順，以化後天之陰；真體已虧者，行有為受化之道，以術退命，順中用逆，以復先天之陽，先後合一，有無兼用，九還七返，歸於大覺，金丹之事了了。

Yang energy is strong and vigorous, while Yin energy is soft and compliant. When they return to their original state, they are still the original substance unified by Earlier Heaven and Later Heaven. From this point on, a new Heaven and Earth are established, and a new furnace is created, practicing the method of "using order within reversal" from Earlier Heaven. This achieves the great elixir known as "nine returns and seven returns." Now, by placing the Earlier Heaven hexagram diagram inside the Later Heaven hexagram diagram, it is to show people that for those whose true essence remains intact, they should follow the path of "non-action and naturalness," relying on the great Dao to preserve their form, practicing "order within reversal" to eliminate the Yin of Later Heaven. For those whose true essence has been lost, they should follow the path of "action and transformation," relying on formulas to renew their life and essence, practicing "reversal within order" to restore the Yang of Earlier Heaven. When Earlier Heaven and Later Heaven are combined as one, both the "having" and "non-having" methods are used together. Through nine returns and seven returns, they return to great awakening, and the matter of the golden elixir is thus completed.

何圖形圓，陰陽合一，無為自然之道也。洛書形方，陰陽分位，有為變化之道也。先天形圓，陰陽一氣，用逆全順，亦無為自然之道也。後天形方，陰陽分判，順中用逆，亦有為變化之道也。

The Yellow River Chart is circular in shape, with yin and yang combined as one, following the path of "non-action and natural spontaneity." The Luo Writing is square in shape, with yin and yang occupying specific directions, following the path of "active transformation." The Earlier Heaven Trigrams diagram is circular, with yin and yang unified as one qi, using reverse methods to achieve the natural order, also following the path of non-action and natural spontaneity. The Later Heaven Trigrams diagram is square, with yin and yang clearly separated, using reverse methods within the natural order, also following the path of active transformation.

河圖先天，皆以道全形之事；洛書後天，皆以術延命之事。先天後天者，即河圖洛書之註釋。河圖洛書，是先天後天之數，先天後天是河圖洛書之理，數得理而始明，理得數而有本。

The Yellow River Chart and the Earlier Heaven Trigrams both discuss "preserving the form through the Dao"—the matter of safeguarding this physical form through the great Dao. The Luo Writing and the Later Heaven Trigrams both discuss "prolonging life through techniques"—the matter of continuing this vital essence through methods and arts. The Earlier Heaven and Later Heaven Trigrams are actually interpretations of the Yellow River Chart and the Luo Writing. The Yellow River Chart and the Luo Writing represent the "numbers" of the Earlier Heaven and Later Heaven Trigrams, while the Earlier Heaven and Later Heaven Trigrams represent the "principles" of the Yellow River Chart and the Luo Writing: numbers require principles to be understood, and principles require numbers to have a foundation.

河圖洛書，相為表裡，先天後天，相為表裡。無洛書，則河圖無變化，無後天，則先天不成全。河圖為洛書之體，洛書為河圖之用。先天為後天之體，後天為先天之用。體用俱備，理數兼該，性命雙修之道，無餘蘊矣。

The River Chart and the Luo Square are complementary to each other, just as the Earlier Heaven and Later Heaven are complementary. Without the Luo Square, the River Chart would not give rise to change; without the Later Heaven, the Earlier Heaven would not attain completeness. The River Chart is the 'body' of the Luo Square, and the Luo Square is the 'function' of the River Chart; the Earlier Heaven is the 'body' of the Later Heaven, and the Later Heaven is the 'function' of the Earlier Heaven. When both body and function are complete, both principle and number are included, and the principle of cultivating both life and nature is fully explained without any omission.

今仿邵子內方外圓之圖，移河圖於洛書之中，移先天於後天之中，河圖洛書為一圖，先天後天為一圖，成內圓外方二圖，以變化內圓外方之義。又以四圖合為一圖，以示圖為活圖，理為活理，不得以圖說圖，以卦說卦也。

Now, following the method used by Shao Yong of the Song dynasty, with the inner part square and the outer part round, place the River Chart within the Lake Chart, and move the Earlier Heaven trigrams into the Later Heaven trigrams. Combine the River Chart and Lake Chart into one diagram, and combine the Earlier Heaven and Later Heaven into another diagram, creating two diagrams with inner circles and outer squares, to illustrate the changing relationship between inner and outer. Then combine these four diagrams into one, to indicate that the diagrams are living diagrams and the principles are living principles, and one should not rigidly interpret the diagrams by means of diagrams or the trigrams by means of trigrams.

以道全形者，圓成無虧，防危慮險之功，誠之者性也。以術延命者，陰陽錯綜，返本還原之道，明之者教也。內方外圓者，自誠而明，無為而抵有為也；外方內圓者，自明而誠，有為而歸無為也。無為了性，有為了命。了性所以成後天之功，了命所以復先天之氣，先天全，後天化，有無不立，性命俱了，現出父母未生以前面目，露出無始五行不到的本橡。圖書，先後八卦，一以貫之，渾然太極，萬象歸空，陰陽混化，無聲無臭至矣。

A person who cultivates "to perfect the form through the Way" has a complete and unimpaired essence, and their practice involves preventing danger and guarding the essence, as described in the "Zhongyong" as "those who achieve sincerity." They approach cultivation by starting from nature. A person who cultivates "to prolong life through techniques" must work within the interplay of yin and yang to return to the original state, as described in the "Zhongyong" as "those who realize clarity." They approach cultivation by starting from teaching. Inner square and outer roundness represent "sincerity leading to clarity," beginning from non-action and reaching action. Outer square and inner roundness represent "clarity leading to sincerity," beginning from action and returning to non-action. Non-action is "realizing the nature," and action is "realizing the life force": realizing the nature completes the practice of the Later Heaven, while realizing the life force restores the original true qi of the Earlier Heaven. When the Earlier Heaven is preserved and the Later Heaven is fully transformed, one no longer clings to either existence or non-existence, and both nature and life force are completed. The original appearance before parents were born is revealed, and the fundamental form beyond the Five Phases is unveiled. The Yellow River Chart, the Luo Writing, and the Earlier and Later Heaven Trigrams all follow the same principle, forming a single Taiji: all phenomena return to emptiness, yin and yang merge into one, and there is no sound or smell. Here, the cultivation comes to an end.

儒曰，執中；道曰，守中，釋曰，虛中。中之一字，乃三教聖人之心法，所以修性命而成大道。千經萬典，說來說去，只說的這一字，篆文中字從○、從|，在人即秉□之良，為至善無惡，圓明不昧之物，所謂先天真一之氣者是也。

Confucianism speaks of "zhí zhōng" (holding the center), Daoism speaks of "shǒu zhōng" (guarding the center), and Buddhism speaks of "xū zhōng" (empty center). The character "zhōng" (center) is the common essential teaching of the sages of the three teachings. It is relied upon to cultivate life and achieve the great way. Thousands of scriptures and myriad classics, when examined thoroughly, all speak of this single character. The seal script character "zhōng" is composed of a circle "○" and a vertical line "｜"; when applied to a person, it refers to the innate knowledge and ability one is born with, which is perfectly good without evil, roundly bright without darkness, that is, what is called "xiān tiān zhēn yī zhī qì" (the true primordial qi of the Earlier Heaven). (The original text here is missing one character, marked as a box, and we dare not make up a guess.)

○中有|，渾然天理，一氣上下，流行不息之義，且|在○之當心，左為陽，右為陰，即河圖左陽右陰。一氣上下之象，薛道光曰：「有物先天地，無名本寂寥，能為萬象主，不逐四時調。」寂寥者，即○。萬象主，即|。至無而含至有，至虛而含至實，故謂中。

A single vertical line standing in the center of the circle represents the unity of heavenly principles, a continuous flow of vital energy moving up and down without interruption. This vertical line is positioned exactly at the center of the circle, with its left side belonging to yang and its right side to yin, matching the pattern of the Yellow River Chart which has yang on the left and yin on the right. This symbolizes the movement of vital energy rising and falling. In the Song dynasty, the alchemist Xue Daoguang wrote four lines of poetry describing something that existed before heaven and earth, nameless and formless, inherently empty and quiet, yet capable of governing all phenomena without changing with the four seasons. In the poem, "寂寥" refers to the circle, and "万象主" refers to the vertical line. From absolute nothingness, there is absolute presence; from absolute emptiness, there is absolute reality, so it is called "center."

是中也，不偏不倚，無前無後，無背無面，無頭無尾，非有非無，非色非空，虛圓不測，無象而能主宰萬象，無形而能造化有形，生天生地生人物。在人，非四大一身之中，非中外之中，無方所、無定位，視之不見，聽之不聞，摶之不得。古人推其理而肖其形，強名之曰「十字街」，曰「四會田」，曰「通衢路」，曰「戊己門」，曰「元牝門」，曰「元關竅」，曰「生殺舍」，曰「刑德門」，曰「生死關」，曰「陰陽戶」，曰「性命竅」，曰「天地根」，曰「人獸關」，曰「懸胎鼎」，曰「造化爐」，名號多端，總而言之，曰「中」。

This "center" is not biased toward any side, nor does it lean toward any end; it has no front or back, no head or tail; it is not existence, nor non-existence; it is not form, nor emptiness. It is empty yet spiritually aware, round yet unfathomable, without form yet capable of governing all forms, without shape yet able to create tangible things. Heaven, earth, people, and all things arise from it. When it comes to human beings, it is neither located in any particular part of the physical body composed of the four elements of earth, water, fire, and wind, nor is it the middle between inside and outside. It has no position, no fixed place; it cannot be seen, heard, or grasped. Ancient sages investigated its nature and compared its form, giving it many names: "Crossroad," "Four Converging Field," "Broad Avenue," "Gate of Wu and Ji," "Gate of Original Mother," "Original Gate," "Gate of Life and Death," "Gate of Punishment and Merit," "Gate of Life and Death," "Gate of Yin and Yang," "Gate of Life and Destiny," "Root of Heaven and Earth," "Gate of Human and Beast," "Suspended Embryo Cauldron," "Cauldron of Transformation." Though these names are numerous, they all ultimately point to one word: "center."

中也者，天下之大本也，亙古聖賢仙佛，皆從此中生出。其大無外，其小無內，放之則彌六合，卷之則退藏於密，悟之者立躋聖位，迷之者萬劫沉淪。蓋此「中」，乃性命之根，在先天，性命如一，而為中（圖）；在後天，中分而為性命（圖），其實後天中返出先夭，性了命凝，性命歸根，仍是一中。

"The Middle" is the fundamental principle of all things in the universe. From ancient times to the present, all sages, immortals, and Buddhas have emerged from this Middle. It is vast without any outer boundary and minute without any inner limit; when expanded, it fills the universe in all directions, and when contracted, it retreats to the most hidden and subtle place. Those who comprehend it instantly attain the rank of sages, while those who lose it will be lost in endless cycles of suffering. Originally, this Middle is the root of both nature and destiny. In the Earlier Heaven, nature and destiny are one, combining into a single Middle (the original text here includes an illustration); in the Later Heaven, this Middle splits into two, giving rise to nature and destiny as separate entities (the original text here includes an illustration). In reality, as long as one can return to the Earlier Heaven state within the Later Heaven, nature will be perfected and destiny will be consolidated, and both nature and destiny will return to their original root, once again becoming that single Middle.

老子云：「谷神不死，是謂元牝。元牝之門，是謂天地根。」紫陽云：「要得谷神長不死，須從元牝立根基。」谷神，即中也。元牝為陰陽，即性命也。谷神不死，中含性命，元牝之基，性命成中。守此中者，聖人也；失此中者，凡人也。聖凡之分，只在得失之間耳。

The sixth chapter of the *Laozi* says: "The spirit of the valley does not die; this is called the original female. The gate of the original female is called the root of heaven and earth." In the Song dynasty, Zhang Boda (who was known as Ziyang) also said: "To obtain the spirit of the valley that does not die, one must first establish a foundation from the original female." Here, "the spirit of the valley" refers to "the center." Originally written as "xuan pu," the term "xuan" was changed to "yuan" by Qing scholars to avoid the name of the sage emperor. One "xuan" and one "pu" represent one yang and one yin, and when applied to human beings, they correspond to sex and life. "The spirit of the valley does not die" means that the center contains both life and sex; "establishing the foundation of the original female" means that only when life and sex are united does the center become complete. Those who can maintain this center are sages, while those who lose it are ordinary people. The distinction between sages and ordinary people lies only in the difference between possession and loss.

一切常人，為氣質所拘，為積習所染，性命分居兩處，中有虧損，日虧日損，性亂命搖，神昏氣濁，將中之原物全然失卻。中一有失，性命無本，形雖動而神已喪，焉能長久乎？三教聖人，以中為本者；欲人執守此中，保全性命耳。

All ordinary people are bound by their innate temperament and gradually tainted by accumulated habits. Their nature and life are separated, and the "middle" between them becomes diminished. Day by day it is lost, day by day it is damaged. Their disposition becomes chaotic, their life force wavers, their spirit becomes dull, and their breath becomes turbid. Eventually, the original "middle" is completely lost. Once the middle is lost, life and nature have no foundation. Although the body may still move, the spirit has entirely vanished. How could this last long? The sages of the three teachings all regard the middle as the fundamental principle, precisely to urge people to firmly hold onto this middle in order to preserve their life and nature.

中之一字，為修道者始終之要著，築基在此，採藥在此，烹煉在此，溫養在此，進陽在此，退陰在此，結丹在此，脫丹在此，七返九還，無一不在此。但這個「中」，人不易見，亦不易知，不可以有心求，不可以無心守。有心求之，則落於色相；無心守之，則入於空寂，均非中道。真正中道，非有非無，即有即無，非色非空，即色即空，不落偏，於恍惚中求，於杳冥內尋，庶乎近焉？

The character "zhong" (center) is the crucial point for a practitioner of the Dao, from beginning to end: laying a foundation here, gathering the elixir here, cooking and refining it here, nurturing it here, "advancing the yang fire" here, "retreating the yin symbol" here, forming the elixir here, and shedding the elixir here. It is said that the "seven returns and nine transformations" have no step outside of this. However, this "zhong" is not easy to see or understand. It cannot be sought with a deliberate mind, nor can it be guarded with an indifferent mind. Seeking it deliberately leads one into form and appearance; guarding it indifferently leads one into emptiness and stillness—both extremes miss the middle path. The true middle path is neither existence nor non-existence, yet it is both existing and non-existing; neither form nor emptiness, yet it is both form and emptiness, not leaning toward either side. One must seek it in a state of vague and dim awareness, and search for it within the deep and mysterious, only then can one approach it somewhat.

天下學人，不知此中是個什麼物事，或謂黃庭穴，或謂天谷穴，或謂百會穴，或謂絳宮，或謂明堂，或謂咽喉，或謂兩腎中間，執守幻身穴竅，便謂守中抱一，妄冀長生，不但不能長生，反而促死，哀哉！

All those who study the Dao fail to understand what the "middle" truly is. Some say it is the Huangting acupoint, others the Tiangu acupoint, others the Baihui acupoint, others the Jianggong, others the Mingtang, others the throat, others the center between the two kidneys. They cling stubbornly to a particular acupoint on their physical body, claiming they are practicing "shouzhong baoyi," and foolishly hope to achieve longevity through this. In the end, they do not attain longevity, but instead hasten their death. How pitiful!

儒曰：「喜、怒、哀、樂之未發，謂之中。」又曰：「不偏不倚之謂中。」道曰：「前弦之後後弦前，藥味平平氣象全。」又曰：「陰陽得類歸交感，二八相當自合親。」釋曰：「吾有一物，上柱天、下柱地，無頭無尾，無背無面。」又曰：「舍利子，色不異空，空不異色，色即是空，空即是色。」此皆言中之實落處也。

Confucianism says: When joy, anger, sorrow, and pleasure have not yet arisen, it is called "zhong" — this is from the "Zhongyong"; it also says: "zhong" is when there is no leaning to one side — this is Zhu Xi's explanation in his "Zhongyong Zhangju". Taoism says: After the upper half-moon and before the lower half-moon, the medicine is balanced and harmonious, and the situation is complete; it also says: Yin and Yang each have their own kind and interact with each other, and when the amounts of two and eight are appropriate, they naturally unite — all from Zhang Bodian's "Wuzhen pian", discussing the midpoint where fire is neither too old nor too tender, and Yin and Yang are each half. Buddhism says: I have something, which supports the sky above and the earth below, has no head or tail, no front or back — this is a saying from the Chan school; it also says: "Sheli zi", form and emptiness are not different, emptiness and form are not separate, form is emptiness, and emptiness is form — this is from the "Prajna Paramita Heart Sutra". All these statements talk about the real and concrete place of "zhong".

若人能於此等處留心，極深研幾，就正於真師，認得真正之中。將柱扙子穿在中鼻孔內，主登彼岸，絕不費力，從此直進大路，緩步而行，終有到家之日，經云：「得其一，萬事畢。」豈虛語哉！

If someone is willing to pay attention to these aspects and thoroughly study the subtle details, then take them to a genuine master for verification, and recognize the true 'center,' it would be like inserting a staff into a bull's nose and leading it along. To cross to the other shore would be effortless. From then on, one can steadily walk on the main path, slowly proceeding, and eventually reach home. The Dao Classic says: 'Mastering one aspect, all things are completed.' Is this not empty talk?