The arrangement of trigrams: The trigrams Qian (Heaven) and Kun (Earth) are assigned to the twelve months.

易之合歲時者，有闢卦序、有六日七分、歲象序。闢卦者，以乾坤二宮卦，除游魂歸魂二卦外，分配十二月：自四月起乾，五月乾之一世姤，六月二世遯，七月三世否，八月四世觀，九月五世剝；十月則為坤，十一月坤之一世復，十二月二世臨，正月三世泰，二月四世大壯，三月五世夬。周而復始，以象二氣之流行，明寒暑之迭更也。

In the Book of Changes, there is a sequence of hexagrams corresponding to the seasonal changes of a year, known as the "辟卦序" and the "six days and seven parts" "岁象序." The term "辟卦" refers to selecting hexagrams from the乾 and坤 trigrams, excluding the two additional hexagrams of wandering soul and returning soul, and assigning them to the twelve months. Starting from the fourth month with the乾 trigram, the fifth month corresponds to the first generation hexagram of the乾 trigram, Guo; the sixth month corresponds to the second generation hexagram, Duan; the seventh month corresponds to the third generation hexagram, Pí; the eighth month corresponds to the fourth generation hexagram, Guan; the ninth month corresponds to the fifth generation hexagram, Po. The tenth month corresponds to the坤 trigram, the eleventh month corresponds to the first generation hexagram of the坤 trigram, Fu; the twelfth month corresponds to the second generation hexagram, Lin; the first month corresponds to the third generation hexagram, Tai; the second month corresponds to the fourth generation hexagram, Da Zhuang; the third month corresponds to the fifth generation hexagram, Guai. This cycle repeats, symbolizing the movement of yin and yang energies and explaining the alternation of cold and hot seasons.

另有分各月屬春夏秋冬四時，而分各宮分配之者，即以震巽二宮分配四孟月，離坎二宮分配四仲月，艮兌二宮分配四季月，而循環交錯，以周一歲，與十二闢卦相應。其取義蓋本周天之數，三百六十；天地主其綱，則半為天，半為地，各得百八十；故以乾坤二宮之卦，分主冬夏。自已至戌，屬天氣，即乾主之；自亥至辰，屬地氣，即坤主之；而更以六子，分象四季之氣。

There is another method of arrangement which assigns each month to one of the four seasons, spring, summer, autumn, and winter, and then distributes them among the eight trigrams: the trigrams Zhen and Xun are assigned the four "first months" (孟月), the trigrams Li and Kan the four "middle months" (仲月), and the trigrams Gen and Dui the four "last months" (季月). This cycle completes a full year and corresponds with the twelve trigrams of the heavenly stem. The reasoning behind this method is based on the number of days in a year, which is 360. The heavens and earth each govern half of this number, 180 each. Therefore, the trigrams Qian and Kun are used to govern the winter and summer ends respectively. From Si to Xu, the half-circle belongs to the heavenly energy, governed by Qian; from Hai to Chen, the half-circle belongs to the earthly energy, governed by Kun. Then, the six sub-trigrams generated from Qian and Kun are used to symbolize the energies of the four seasons.

震巽為長，乾坤之長男長女，故震配春夏二孟月，即正月四月；巽配秋冬二孟月，即七月十月。坎離為中男中女，故配四仲月，即二五八十一月；艮兌為少男少女，故配四季月，即三六九十二月。如是乾坤二宮總主一歲，猶二氣之升降消息也。

Zhen and Xun are the eldest son and eldest daughter born from Qian and Kun, so Zhen is paired with the first months of spring and summer, that is, the first and fourth months; Xun is paired with the first months of autumn and winter, that is, the seventh and tenth months. Kan and Li are the middle son and middle daughter, so they are paired with the second months of the four seasons, that is, the second, fifth, eighth, and eleventh months; Gen and Dui are the youngest son and youngest daughter, so they are paired with the last months of the four seasons, that is, the third, sixth, ninth, and twelfth months. In this way, the two trigrams Qian and Kun oversee the whole year, just as the rise and fall of yin and yang energies.

震巽六子分主四時，猶五行之分合生化也。故一年三百六十餘日，合之於六子之爻，亦三百六十爻；乾坤二宮，則合十二月。雖綱目交錯，日月代嬗，若不相接，實則後天二五生化，固交錯而行，代嬗以成，非復先天之單純也。故卦象往復，爻象錯雜；氣數相間，循環無盡。雖以一歲為例，非限於歲月也。

The six subordinate trigrams, such as Zhen and Xun, govern the four seasons, just as the Five Phases interact through generation, transformation, and mutual restriction. Therefore, the 365 days of a year correspond exactly to the 365 lines of the six subordinate trigrams. The two main trigrams, Qian and Kun, correspond to the twelve months. On the surface, the main and subordinate trigrams appear to be interwoven, with the sun and moon alternating, seeming disconnected. In reality, the Later Heaven's transformations depend on the interaction of yin and yang and the Five Phases, the "two and five," which alternate and succeed each other. This is different from the Earlier Heaven, which is simpler. Thus, the trigrams have movement and return, the lines are varied and complex, the qi and numbers alternate, and the cycle has no end. Although this passage uses the year as an example, it is not limited to the year.

本來卦象，無所不包；其序既殊，其用自異。而一歲氣數，恰符周天之數；日月推行，恰符陰陽消息之度。遠者可譬於近，難者可喻於易；就其簡明者衍之，足以推於精微，極於高深；非日六十四卦，專為歲序用也。故此歲序之易，亦言易之一例，有不可不知者焉。

The images of the hexagrams originally encompass everything, but since their sequences differ, their uses naturally vary. The cycle of a year precisely corresponds to the number of the celestial circle, and the movement of the sun and moon exactly matches the measure of the waxing and waning of yin and yang. Far things can be compared with near ones, and difficult things can be explained by simple ones. By following this clear cycle of a year, one can extend it to reach subtle and profound understandings. This does not mean that the sixty-four hexagrams were specifically created for the sequence of the years. Therefore, this "annual sequence" section of the Book of Changes is merely one example of interpreting the Book of Changes, yet it is essential for those studying the Book of Changes to understand.

六日七分歲象序者，以全易六十四卦分配一歲，而將坎離震兌四卦，當二至二分：震主春分，離主夏至，兌主秋分，坎主冬至，謂之四正。餘六十卦，以每月五卦，一卦主六日七分。因一歲三百六十五日又四分一，則卦六十合三百六十爻；每日八十分，一卦合六日七分，恰當一歲之數。

The concept of "six days and seven parts" in the annual sequence of the heavenly phenomena refers to the distribution of all sixty-four hexagrams throughout the year. The four trigrams Kan, Li, Zhen, and Dui correspond to the solstices and equinoxes: Zhen governs the spring equinox, Li governs the summer solstice, Dui governs the autumn equinox, and Kan governs the winter solstice, known as the "four cardinal" trigrams. The remaining sixty hexagrams are divided monthly, with each hexagram governing five days and seven parts. Since a year consists of 365 and 1/4 days, the sixty hexagrams together total 360 lines. Dividing a day into eighty parts, each hexagram corresponds to six days and seven parts, exactly matching the number of days in a year.

其氣始於中孚，其時始於冬至之月。由復至咸，共半歲，為八十八陽爻，九十二陰爻；自姤至中孚，亦半歲，為八十八陰爻，九十二陽爻，恰當百八十爻，而主陰陽寒暑之數。而中孚至復，咸至姤，恰得六日七分，定為例，實天時之度數，自然之序也。

This set of hexagram sequence begins with Zhongfú hexagram, and the corresponding season starts from the month of Winter Solstice. From Fu hexagram to Xian hexagram is half a year, containing eighty-eight yang lines and ninety-two yin lines; from Guo hexagram to Zhongfú hexagram is also half a year, containing eighty-eight yin lines and ninety-two yang lines. Each of them exactly consists of one hundred and eighty lines, used to govern the measure of yin and yang, cold and heat. From Zhongfú to Fu, and from Xian to Guo, the interval is exactly six days and seven parts, which is established as a general rule. This is indeed the measure of heaven's time, a natural order.

卦以交錯，爻以次第；一升一降，一往一復；象氣之周行，後天生化之例也。故其序可以紀歲候時，可以占天驗氣；即四正之卦，分管四時，以候四氣；春夏秋冬有其序，生長收藏有其令；木以長春，火以長夏，金以長秋，水以長冬；五行不失其常，二氣不亂其道；以往復循環無盡，而消息進退可見；其易之傳，蓋已久矣！

The trigrams interconnect with each other, and the lines connect in sequence, rising and falling, moving forward and returning, symbolizing the circulation of qi. This is the principle of generation and transformation in the Later Heaven. Therefore, this sequence of trigrams can be used to record years and observe time, and to predict celestial phenomena and detect the movement of qi. Take the four cardinal trigrams, which govern the four seasons, and are used to measure the qi of each season: spring, summer, autumn, and winter each have their order, and growth, flourishing, harvesting, and storage each have their proper time. Wood thrives in spring, fire is vigorous in summer, metal is mature in autumn, and water is stored in winter. The Five Phases do not deviate from their regular course, and the two energies of yin and yang do not disorder their principles. Because this process of rising and falling, circulating and returning has no end, the waxing and waning, advancing and retreating are clearly visible. This system of the Book of Changes has been passed down for a very long time.

蓋自黃帝造甲子，曆數漸明；堯舜之時，曆象尤備。其制仿於易卦，本於河洛之圖，合於日月之紀，非率爾之作也。《易傳》曰：「懸象著明，莫大乎日月。」日為陽，月為陰；後天之離坎，代先天之乾坤，故歲象以坎離為主，當冬夏二至。冬至為陽生陰消，夏至陰生陽消。

Since the Yellow Emperor established the Jiazi system, the calendar became gradually clear; by the time of Yao and Shun, the system of observing celestial phenomena and setting the time was especially complete. These systems were modeled after the trigrams of the Book of Changes, based on the Yellow River Chart and the Luo Writing, and in harmony with the cycles of the sun and moon, not made up arbitrarily. The Book of Changes, Great Treatise Upper Transmission says: "The suspension of celestial phenomena and their clear manifestation, nothing is greater than the sun and moon." The sun belongs to yang, the moon to yin; in the Later Heaven arrangement, the trigrams Li and Kan replaced the trigrams Qian and Kun from the Earlier Heaven. Therefore, the sequence of the "Annual Phenomena" trigrams takes Kan and Li as its main trigrams, corresponding to the two extremes of the solstices. The winter solstice marks the beginning of yang energy and the gradual decline of yin energy, while the summer solstice marks the beginning of yin energy and the gradual decline of yang energy.

實一歲寒暑之樞機，而四時氣候之中宰。震司春分，如日之升；兌司秋分，如月之上；為陰陽之管鑰，實歲時之道路。皆為氣數所至，而象最明。以之合時令，則足為歷家之所法；以之體天道，則足為生化之模範。

These two solar terms are indeed the key points of the year's cold and heat, as well as the central governing forces of the four seasons' climate. The Zhen trigram governs the spring equinox, like the sun just rising; the Dui trigram governs the autumn equinox, like the moon waxing. They are the keys to the entry and exit of yin and yang, and the channels through which the annual cycle operates. These are the natural results of the flow of qi, and the trigrams clearly manifest these phenomena. Using them to coordinate with the seasons provides a reliable basis for those who compile calendars; using them to understand the heavenly way offers a model for the operation of generation and transformation.

蓋其序之取義，雖近闢卦，而尤善焉。不過闢卦法乎先天，故以乾坤二宮，為一歲之綜；而歲象法乎後天，故以坎離四正，為一歲之綱。先天乾坤對位，主於上下，此伏羲八卦之序；後天坎離震兌分主四正，此文王八卦之序。二者各有取義，而後者最宜於後天之用，以所象無不交錯往復，所配皆以消長平均，以合一陰一陽之道，而能會通日月之行也。

This sequence of hexagrams is similar in meaning to the method of dividing the trigrams, but it is more comprehensive. The method of dividing the trigrams follows the Earlier Heaven arrangement, using the trigrams Qian and Kun to represent the whole year; the annual pattern follows the Later Heaven arrangement, using the four cardinal trigrams Kan, Li, Zhen, and Dui as the framework for the year. In the Earlier Heaven arrangement, Qian and Kun are opposite each other and govern the upper and lower positions, which is the order of the Eight Trigrams of Fuxi. In the Later Heaven arrangement, Kan, Li, Zhen, and Dui each govern the four cardinal directions, which is the order of the Eight Trigrams of King Wen. Each has its own meaning, but the latter is more suitable for practical use in the Later Heaven system, because the trigrams it uses are interwoven and reciprocal, and the paired seasonal periods are balanced in their waxing and waning, conforming to the principle in the Great Treatise that "the way is characterized by the interplay of yin and yang." Thus, it can integrate the movement of the sun and moon.

故中國之曆法，實本此序；而後人以之占筮，亦無不驗。其為易之精妙，亦足與《周易》相證；即合之其它各易，不問為先天後天，亦無不貫通。要以後人多不明其用，忽其旨趣；門戶之見，以責難之；方技之辭，以鄙夷之；遂使上古流傳之易，反為俗人所訛，豈不惜歟！

Therefore, the Chinese calendar is actually based on this sequence of hexagrams; later people used it for divination, and it never failed to be accurate. Its refined aspects in the study of the Yi (Book of Changes) are sufficient to corroborate the Zhou Yi; even when applied to other schools of Yi methodology, whether earlier Heaven or later Heaven, it is fully consistent. Alas, most later people do not understand its use and overlook its meaning: some criticize it with narrow-mindedness, while others belittle it as mere words of the alchemists and look down upon it. Thus, the Yi methodology passed down from ancient times has been wrongly transmitted and misunderstood by the common people. Is this not regrettable?

周易之用，在乎人之誠，不必一例。如周易之序，固為周時太卜所司；而太卜所用，兼及連、歸，不限文王之易也。則可知易之為用，不以序為限；但有是序，即有是變；有是變，即有是用。伏羲之易，有伏羲之用；文王之易，有文王之用。夫子合二者而作雜卦序，即夫子之易，亦有夫子之用也。

The function of the Zhou Yi lies entirely in the sincerity or lack of sincerity of those who use it, and there is no fixed pattern that remains unchanged. Just as the sequence of hexagrams in the Zhou Yi was originally managed by the official "Tai Bu" in the Zhou dynasty; yet the Tai Bu also used the Lian Shan and Gui Zang, not limited to the Yi of King Wen alone. From this we can see that the function of the Yi is not restricted by any particular sequence of hexagrams: there is such a sequence, there is such a change; there is such a change, there is such a method of use. The Yi of Fuxi has its own method of use; the Yi of King Wen has its own method of use. Confucius combined the Earlier Heaven and Later Heaven sequences to compose the Zage sequence, showing that the Yi of Confucius also has its own method of use.

推之連山之易，有連山之用；歸藏之易，有歸藏之用；八宮之易，有八宮納甲之用；歲象之見，有六日七分之用，分而言之，各有其用；合而通之，則易之用，廣無不包，變無可窮；而能通之為一者，則見天地之心；斯非聖知不克也！就其最簡易者，則但執一易；審其象，參其數，列其圖；而合其先後天，明其辭而衍之經與傳，則亦可以得易之用矣！

From this, we can extend further: The Book of Linked Mountains has its own usage, and the Book of Return and Concealment has its own usage; the eight palaces of the Book of Changes have the method of "eight palace stem assignment"; the annual phenomena of the Book of Changes have the method of "six days and seven parts." When considered separately, each has its own use; when combined and integrated, the function of the Book of Changes is vast and all-encompassing, its transformations numerous and endless. Only those who can integrate them into one can see the heart of the continuous generation of heaven and earth, something that cannot be achieved without the wisdom of a sage. If one starts from the simplest approach, then one may just fix upon a single Book of Changes: examining its hexagrams, investigating its numerical principles, arranging its diagrams, and combining them with the Earlier Heaven and Later Heaven views. Clarifying its hexagram line statements, and deriving the commentaries from the classics, one can also attain the function of the Book of Changes.

故易之種類雖眾，精其一者，能通其餘；若一而未精，雖多奚益？目迷於象數之異，手迷於圖表之繁，能紀其粗，而遺其精；逐其物、忘其神；則為易百年，曾不得易道之一二；此後世有掃象之說也。

Therefore, although the types of the Yi are numerous, mastering just one can lead to understanding the rest through analogy; if one does not master even one, how can learning more be of any benefit? The eyes are confused by the differences among various schools of imagery and numbers, and the hands are tangled by the complexity of different charts. One remembers only superficial details but misses the essential core; chasing external phenomena while forgetting the inner principles. Thus, studying the Yi for a hundred years would still yield only a fraction of its true meaning. This is the root cause of the later saying "sweeping away images."

夫易之本在象，而掃之，將何以見易？豈非以世人之馳於外，而遺其內；求其未，而棄其本歟！故習易者，必先去其蔽，所敝者，多而不精，博而不深；能於貌，而不及於神；以為能通習，而不知無一得也。

The fundamental aspect of the Book of Changes lies in 'image' or 'symbol'. If one clears away the images, what else is there to see in the Book of Changes? This is precisely because people have been blindly seeking outwardly and have lost their inner essence, chasing superficial details while abandoning the root. Therefore, those who study the Book of Changes must first remove their obstructions. These obstructions refer to learning a lot but not mastering it, exploring widely but not deeply; merely imitating the surface without reaching the profound meaning; believing oneself to have fully integrated and understood, yet actually achieving nothing.

故各易之序，夫子不錄；僅取文王者著為經，而集其它關乎易理者，述之為傅；做學者知所宗，而不紛其智，知所本，而不亂其思；庶由一以通其餘，由易以達事難，由近以賅其遠；則習之有成，而易道亦不荒塞；此則夫子刪易之微旨也。

Therefore, the various sequences of hexagrams in different schools were not all collected by the Master. He selected only one sequence from King Wen and established it as the "Classic," while gathering other materials related to the principles of the Book of Changes and compiling them into the "Commentaries." This was to enable those studying the Book of Changes to know what to revere, so their thoughts would not become confused, and to know what to rely on, so their reasoning would not become disordered. In this way, one could start from one comprehensive principle and extend it to all others, proceed from the easy to the difficult, and from the near to the distant. By following this path, one could achieve mastery, and the teachings of the Book of Changes would not be neglected or blocked. This is the profound intention of the Master in editing the Book of Changes.

夫易之致用，非為卜筮也；若為卜筮，則巫祝在，夫子不以之首六經也；夫子以易為六經之首者，以其用明天人之道，類萬物之情；定日月之行，奠山河之度；可以致治平之業，可以正性命之功；可以四達神鬼之情；可以敷教化之德；故其用在此，而不為卜筮也。

The usefulness of the Book of Changes lies not in divination. If it were solely for divination, there would be others, such as the shamans and diviners, who would handle that. Confucius would not have placed the Book of Changes first among the Six Classics. Confucius placed the Book of Changes first among the Six Classics because its function is to clarify the communication between heaven and humanity, to classify and compare the nature of all things; to determine the movement of the sun and moon, to establish the measurements of mountains and rivers; to achieve the affairs of governing the country and pacifying the world, to correct the cultivation of human nature and the attainment of destiny; to understand the hidden feelings of ghosts and spirits, and to spread the virtue of teaching and moral cultivation. Its usefulness lies here, not in divination.

然卜筮亦易所固有，卦爻之辭，吉凶之占；悔吝之途，君子小人之道；皆著於象數，徵於言文；苟按其數而卜之，因其辭而決之；則所謂易逆數也。通變化而行鬼神者，皆在傳中揲卦之法，可見之也；故經不備者，傳則補之；經取其約，約而后尊；傳取其博，博而後宏。

But divination is indeed an inherent part of the Book of Changes: the hexagram statements, line statements, the determination of fortune and misfortune, the tendencies of regret and hardship, and the paths of the gentleman and the petty person—all rest upon the images and numbers, and are verified in the textual expressions. If one divines by following the hexagram numbers and makes decisions based on the line statements, this is what the "Commentary on the Hexagrams" refers to as "the Book of Changes is about inverse numbers." As for the principles of continuous transformation and the operation of spirits and ghosts, these are evident in the method of "casting yarrow stalks to form the hexagram" described in the "Great Treatise." Therefore, the classic text does not cover everything, and the commentaries supplement it. The classic is concise, and only through conciseness does it become dignified; the commentaries are comprehensive, and only through comprehensiveness do they become grand.

用宏而道尊，則易之精粗皆備；故傳所舉者，有各易之例；凡連山歸藏之類，八宮歲象之圖；上自先天，旁及河洛，無不徵取，以為周易之輔，而明易道之大也。故讀經則專文王之制，雖伏羲之序不列；讀傳則必廣搜各易之圖，而不限於一種；此講易時必旁及各序也。

The scope of application is vast and the principles are dignified, encompassing both the subtle and the superficial aspects of the Book of Changes. Therefore, the "Commentaries on the Book of Changes" include the systems of various schools of the Book of Changes: all kinds of diagrams such as the Eight Trigrams and the annual phenomena, tracing back to the Earlier Heaven trigram positions, and extending to the Yellow River Chart and the Luo Writing, are all cited and adopted as auxiliary materials for the Zhou Changes, to demonstrate the vastness of the principles of the Book of Changes. Therefore, when reading the classics, one should focus solely on the system of King Wen, even excluding the trigram sequence of Fuxi. However, when reading the commentaries, one must widely collect the diagrams of various schools of the Book of Changes, not limited to one system. This is why, when discussing the Book of Changes, it is necessary to refer to various trigram sequences.

人或疑其言之雜，不知正欲其雜也；人或謂異於經文，不知正求其異也；雜則變例多，而用可廣；異則分類明，而道可通；此傳之本旨，夫子訂易之徵意也。故傳中之辭，各不相類；方位次序各不同；名類上下各不一，其所以然者，各易之原制如是也。

Some people doubt that the "Commentaries on the Changes" are too miscellaneous, but they do not realize that it is precisely meant to be miscellaneous. Others say that the commentaries are inconsistent with the classic text, but they do not understand that it is precisely meant to be inconsistent. Being miscellaneous allows for a greater variety of flexible applications, making it more useful; being inconsistent allows for clear categorization, enabling the principles to be fully understood. This is the true intention of composing the commentaries, as well as the profound purpose of Confucius in establishing the study of the Changes. Therefore, the words in the commentaries are not similar to each other, their positions and orders differ, and their titles and arrangements are also inconsistent. This is because the original forms of the Changes themselves were inherently varied.

各易皆可用於卜筮，而周易最善；其次則八宮納甲法，其次則歲象六日七分術；而伏羲先天本卦方圓序，則為示修養之道，明先天之氣；若用於卜筮則淺矣！然亦能通，不過難測耳；至俗傅各種卜易法，皆由數者變化而來，有當有未當也；與周易等者，前有連山、歸藏，後有夫子雜卦；皆以卦爻象數為本，不取甲辰，不用日月；其道簡而理微，人多難知；故卜者不用，而好八宮與歲象術；其實理數一也，苟通者無所忤焉。

All schools of divination using the Yi can be used for divination, among which the Zhou Yi is the most complete; next comes the method of the Eight Palaces with the stem assignment, and then the method of the annual cycle and six days and seven parts. As for the square and circular diagrams of the Fuxi Earlier Heaven primary hexagram, they were originally used to indicate the way of cultivation and to clarify the primordial qi. If they are used for divination, they become superficial; however, they can also be used, though it is difficult to measure. As for various methods of divination that are popular among the common people, they all originate from the above-mentioned schools, some being appropriate and some not. Those that can be compared with the Zhou Yi include the Lianshan and Guicang, and later the Zazha by the Master, all of which take the hexagram lines and numbers as their foundation, not using the heavenly stems and earthly branches, nor the sun and moon. Their methods are simple but their principles are subtle and profound, so they are not easy to understand for ordinary people. Therefore, diviners do not use them, but prefer the methods of the Eight Palaces and the annual cycle. In reality, the principles and numbers are the same. If one truly understands them, using any of these methods will not feel contradictory.

做周易之卜，古之史傳常見其例；其應甚靈，豈古可用，而今不宜哉？蓋用之在人，能誠而通神者，何易不可靈？否則雖俗淺之術，亦不得其效；故易之用，不在序之異也；序之所異，不為卜也；其理見前，可以知矣。周易之精，在以後天之物象，明先天之氣數；一卦一爻，各有所象，而貫通先後天，以明其變化；故不枝不離，而獨來獨往；為最宜於時中之道，合於戒慎之教也。

Divination using the Zhou Yi is commonly found in ancient historical records, and its predictions are very accurate. How could it be that ancients could use it, yet modern people should not? Actually, the key lies in the person using it: if one is sincere and communicates with the divine, then which divination method would not be effective? Otherwise, even using secular and simple methods would not work. Therefore, the function of the Zhou Yi does not lie in the differences of its hexagram sequences. The differences in the sequence of hexagrams were not originally intended for divination, as this reasoning has already been explained earlier, and now it should be clear. The profound aspect of the Zhou Yi lies in using later heaven phenomena to explain the earlier heaven principles of qi and numbers. Each hexagram and line has its corresponding image, and it can connect both earlier and later heaven, clearly explaining the changes within. Therefore, it does not branch out into irrelevant matters, nor does it depart from the fundamental principles. It moves independently and freely, most in line with the principle of "timeliness and moderation" and also conforms to the teaching of "caution and reverence."

以文王作此，正囚辱之時；憂天下之亂，存革正之心；鑑前人之敝，立新教之意；故其辭巽而決，其旨正而中，其道極變化，而仍守常度；其志攘暴亂，而先重仁德，故與夫子中庸之教，修道戒慎為本；忠恕時中為用，立誠復始為成，其義正同。

Because King Wen composed this Book of Changes while he was imprisoned and humiliated, he was concerned about the troubles of the world and had the determination to reform corrupt governance and restore proper order. Taking into account the accumulated evils of previous generations, he intended to establish a new teaching. Therefore, his words were humble yet resolute, his principles upright and moderate; his doctrines reached the utmost of change yet remained within the constant path; his aspirations aimed to eliminate tyranny, yet he first valued benevolence. This aligns perfectly with the teachings of the Master's Doctrine of the Mean, which takes cultivating the Way and being cautious as its foundation, practicing loyalty, forgiveness, and timely moderation as its functions, and establishing sincerity and returning to the original nature as its achievement.

夫子取之以繼堯舜之傳，而明文武之治，即所謂祖述憲章者，易經居其首也，中庸之書，繼易而作；皆言事而歸於道，言人而歸於天，原怡返終，正其性命，明物達情，通其精粗；故言博而約，辭詳而明；為古聖心傳之所存，而儒家至教之所寄也。後之學者當加意焉！

The Master took up the Zhou Yi, aiming to carry forward the heart method passed down from Yao and Shun, and to clarify the governance principles of King Wen and King Wu. This is exactly what the Zhongyong says: "Following the path of Yao and Shun, and establishing the model of Wen and Wu." The Yi Jing stands at the beginning of this. The Zhongyong itself was written in succession to the Yi. Both deal with matters and return to the Dao, with people and return to Heaven; they trace back to the origin and seek the ultimate, correct human nature and life; they clearly observe all things and understand the nature of things, integrating the subtle and the obvious. Therefore, their writings are extensive yet concise, their expressions detailed yet clear. This is where the sacred heart tradition of the ancients is preserved, and where the highest teaching of Confucianism is entrusted. Later scholars should focus on this aspect.

夫子刪定六經，取文王之易為首，同於《尚書》，為三代以上之遺；於此可見二帝三王之政教，神農伏羲之制作也；而不取《連山》《歸藏》，及伏羲神農之易，獨採文王者，為文王之易，即各家之所傳；傳至文王變例已多，易道更明，易習易知也。伏羲神農堯舜之時，有象無文，有文未備；《連山》《歸藏》之易，有文異義，有變未全；唯文王之易，象仍古昔，文備義明；變推新例，體具用昭；故言易至文王，為最宜於時之制，而易道亦更發皇光大矣！

Confucius compiled the Six Classics, placing King Wen's Book of Changes first, just as the Book of Documents is arranged, both being ancient traditions passed down from the Xia, Shang, and Zhou dynasties. From these texts, one can see the political and educational practices of the two emperors, Yao and Yu, and the three kings, Xia Yu, Shang Tang, and Zhou Wen Wang, as well as the inventions of Shen Nong and Fuxi. He did not adopt the books of Lianshan and Guicang, nor the Book of Changes attributed to Fuxi and Shen Nong, but only used King Wen's version, because King Wen's Book of Changes had already integrated the teachings of various schools. By the time it reached King Wen, the system of change was already well developed, the principles of the Book of Changes were clearer, and it was easier to learn and understand. In the time of Fuxi, Shen Nong, Yao, and Shun, there were hexagrams but no written explanations, and even if there were explanations, they were incomplete. The two books of Lianshan and Guicang had written explanations but their meanings differed, had examples of change but were not comprehensive. Only King Wen's Book of Changes maintained the ancient method of hexagrams, had complete written explanations, clear principles, and further developed new examples of change, making its system complete and its functions clearly evident. Therefore, when discussing the Book of Changes, it was only when reaching King Wen that it fully aligned with the contemporary system, and the principles of the Book of Changes were thus further promoted and expanded.

此夫子序易，以周易為本者也；然周易雖善，舊制亦不可盡棄；伏羲之作，固為易之源，不可不知；即神農堯舜夏商之易，亦不可不明；則將其說備載於傳，繫之於經，故曰繫辭。而以證諸經文，廣其變，推其用也。

This is the reason why the Master arranged the Book of Changes with the Zhou Yi as its foundation. However, although the Zhou Yi is excellent, the old system cannot be entirely discarded: Fuxi's creation is indeed the origin of the Yi, and it is essential to know it; even the Yi of Shen Nong, Yao, Shun, and the Xia and Shang dynasties should not be overlooked. Therefore, these views were thoroughly recorded in the "Transmission" and attached beneath the classic text, hence called the Great Treatise, to verify the classic text, expand its variations, and elaborate on its applications.

故有先天乾坤上下之位序，為伏羲之遺，即天地定位一章所述也；有日月成歲，合乎天行之序，即揲蓍求卦象一歲之一章所述也；有納甲應爻，分宮飛伏之序，即出震齊巽，先甲後甲各所述也；有日月代行，水火上下之序，即後天卦位，三索得男女各節所述也。

Therefore, the transmission contains the earlier heaven arrangement where Heaven is above and Earth is below, which is the old system left by Fuxi, as discussed in the chapter "Heaven and Earth are positioned" of the "Discourse on Hexagrams"; the sequence of hexagrams formed by the movement of the sun and moon completing a year, conforming to the movement of heaven, is explained in the chapter "Divination with the Yarrow Stalks, the day of the appointed period" of the Great Treatise; the assignment of heavenly stems to lines and the sequence of hexagrams involving division of palaces and flying and hiding lines is discussed in the "Discourse on Hexagrams" chapter "The Emperor arises from the震 (Thunder) and harmonizes with the巽 (Wind)" and the text mentioning "three days before the Jiā day and three days after the Jiā day"; the sequence of hexagrams showing the mutual movement of the sun and moon and the mutual assistance of water and fire above and below is explained by the later heaven hexagram positions and the sections in the "Discourse on Hexagrams" titled "Three searches result in male and female."

其它如地代有終，《歸藏》之羲也；艮為終始，《連山》之義也；方圓之圖，伏羲之制也；納甲納音，黃帝之制也；歲象闢卦，神農之制，及於堯舜，而更推衍者也；九宮五行，五運六氣，河洛之遺，及於黃帝，而更發明者也。

Other expressions such as "the earth path signifies the end" reflect the meaning of the book of Guizang; "Geng signifies the beginning and the end" reflects the meaning of the book of Lianshan; the square diagram and the circular diagram were created by Fuxi; the system of Na Jia and Na Yin were established by the Yellow Emperor; the system of annual phenomena and the method of dividing trigrams were developed by Shen Nong, and later refined during the time of Yao and Shun; the nine palace system of the Five Phases and the theory of the Five Movements and Six Qi were remnants left by the Yellow River Chart and the Luo Writing, and were further elaborated during the time of the Yellow Emperor.

故易者成於各聖，傳於千古，而其義備於傳，以與周易證明也。夫子猶以為未足，更合伏羲文王之作，先後天之象，各家之制，而成雜卦傳；雜者合也，合各種而一之，以見其會通一貫之義也；故以之終諸書，而成夫子之易，是易雖取文王，而仍包各書，夫子之作亦附焉，此讀者所宜知也。

Therefore, the book of Change (Yi) is a work completed by sages of all generations and passed down through the ages. Its principles are fully explained in the "Transmission" (Zhuan), used to verify the Zhou Yi. Confucius still found it insufficient, so he combined the works of Fuxi and King Wen, the earlier and later heavenly diagrams, and the systems of various schools, to compose the "Miscellaneous Diagram Transmission" (Zagua Zhuan). "Miscellaneous" means combination, bringing together various elements into one, to show their unified meaning. Hence, it is placed at the end of the various chapters, completing Confucius' own version of the Yi. This shows that although the Yi is taken from King Wen's school alone, it still includes the works of other schools, and Confucius' own writings are also included. This is something those who study the Yi should know.

易之致用，一而已；一者道也，故各易，皆為明道用；無論為伏羲，為文王，為先天後天，為《連山》《歸藏》，皆不離於道；然道自一，何以各易不同？則為明道之方，有不同耳，道本無方無體，人之求之也，則有其方，以悟其體；是猶行路，或車或馬或步行，其行一也；所以行不同也，故各易各有其方，以明其用。

The function of the Book of Changes ultimately comes down to one thing, which is the Dao. Therefore, all schools of the Book of Changes are established to explain the Dao. Whether it is the Book of Changes of Fuxi, the Book of Changes of King Wen, whether it is Earlier Heaven or Later Heaven, whether it is the Book of Continuous Mountains or the Book of Returning Concealment, none of them deviate from the Dao. However, the Dao is originally one, so why do the various schools of the Book of Changes differ? This is only because the approaches to explaining the Dao differ. The Dao itself has no place or form, and in order to seek it, people must have a path or method to understand its essence. This is like traveling, whether by carriage, horseback, or on foot; the act of traveling is the same, but the methods differ. Therefore, each school of the Book of Changes has its own approach, to demonstrate its function.

在太上之時，道至簡，事至略；人樸物醇，生計至易；故象之者，亦直樸無文，而見道亦真；其後則漸降漸變，漸繁而文；而象之者，隨之而異；故易自古入今，自簡趨繁，人事使然；道之為道，固未改也。故一易之用，為應時之需；時之不居，易亦必變，此易之所以為易也。

In ancient times, principles were extremely simple, affairs were very straightforward, people's hearts were pure, things were naturally sincere, and livelihood was very easy. Therefore, the images used in the hexagrams were direct and unadorned, yet they truly reflected the way. Later, as the world's customs gradually declined and changed, things became more complex and more elaborate, and the images used in the hexagrams also changed accordingly. Therefore, from ancient times to the present, the Book of Changes has evolved from simplicity to complexity, which is due to human affairs. However, the way itself has never changed. Therefore, every use of the Book of Changes is to meet the needs of its time. Since circumstances never stop, the Book of Changes must also change accordingly. This is precisely why it is called the "Book of Changes" (Yi), meaning change.

伏羲之易，名為先天，義為修道，政尚虛靜，教崇純樸，其時然也；神農黃帝以迄堯舜，生息日眾，世事日新；政日以備，教日以詳；善惡以明，吉凶斯判；故其易亦由簡而繁，其用由純而雜；堯舜之後，文勝於質，政明於教；禮備於德，事增於物；變化既多，氣數以分；於是三代之易，更張其舊，名適時宜，以為新制。

Fuxi's Book of Changes is called "Earlier Heaven," and its meaning lies in cultivating the Way. In terms of governance, it values emptiness and quietude; in terms of education, it values simplicity and purity. That was the situation of the time. From Shen Nong and the Yellow Emperor down to Yao and Shun, the population grew increasingly numerous, and worldly affairs became more and more new. Orders became more and more complete, and education became more and more detailed. Thus, good and evil became clearly distinct, and auspicious and inauspicious became clearly separated. Therefore, the Book of Changes at that time changed from simple to complex, and its use changed from pure to mixed. After Yao and Shun, ornamentation surpassed simplicity, and orders surpassed education. Rituals were complete compared to virtue, and affairs outnumbered objects. With many changes, the destiny and fortune thus differentiated. Therefore, the Book of Changes of the Xia, Shang, and Zhou dynasties altered the old system, established new names to suit the times, and became a new system.

至文王而變益異，時勢既迫，事物乃非；道晦不明，教亡不復；政失其紀，俗失其常；善不敵惡，吉不侔凶；君子道消，小人在位；易道至是窮矣！窮則必變，敝則必革；此湯伐桀之時也；文王師之，以變為新易，而寓教於卦象焉；故周易者，革舊改新，正教明道者也。

By the time of King Wen, the changes became even more different: the situation had become urgent, things had already changed beyond recognition; the Way was obscured and unclear, education had declined and could not be restored; government orders had lost their order, and customs had lost their proper course; good could not overcome evil, and good fortune could not surpass misfortune; the Way of the gentleman had receded, while petty men occupied high positions; at this point, the Way of the Changes had reached its limit. When something reaches its limit, it must change, and when something is in disrepair, it must be reformed, just as was the case when Tang of Shang attacked Jie of Xia. King Wen took the example of Tang, using the method of change to create a new Changes, entrusting education in the images of the hexagrams; therefore, the book of The Zhou Changes is precisely a book for eliminating old evils, establishing new laws, rectifying education, and explaining the great Way.

當時晦塞，值身窮因，而欲為此挽回教政，光復道德，其非易事。蓋可知矣。故其為象曲折反覆，為辭宛委丁寧；一變前日之作，而成獨有之制；此其與伏羲之舊大殊，與連歸之辭亦異；而成一後天之易也。

At that time, the world was dark and obstructed, and King Wen himself was in a difficult situation. Yet he wished to use this book to restore moral teachings and political orders, and revive virtue. How difficult this must have been, one can easily imagine. Therefore, the hexagrams he selected were intricate and complex, and the accompanying texts were subtle and repeated for emphasis. He completely changed the previous style, creating a unique system. This is why it differs greatly from Fuxi's original system, and also differs from the wording of the "Lianshan" and "Guicang," thus becoming its own form of Later Heaven Yi.

蓋文王之易，與時相宜；後天者，奉時也；本無先後天之名，以別於伏羲，故曰後天；以能奉天時，故曰後天；其實易一也，用異耳；若分先後，則文王以前者，皆宜先之；伏羲以後者，皆宜後之；而獨先伏羲後文王者，以二易足盡易之體用耳。

King Wen's Yi is in harmony with the times. The term "Later Heaven" refers to following the heavenly timing. Originally, there were no names like "Earlier Heaven" or "Later Heaven." These terms were introduced to distinguish King Wen's Yi from Fuxi's Yi. It is called "Later Heaven" because it follows the heavenly timing. In reality, there is only one Yi, differing only in its application. If we were to divide based on time, everything before King Wen should be considered Earlier Heaven, and everything after Fuxi should be Later Heaven. However, Fuxi is regarded as Earlier Heaven and King Wen as Later Heaven because the Yi systems of these two sages have already fully explained the nature and application of Yi.

若推而言之，則連、歸各易，皆後天也；以其明伏羲之變，同於周易也；不過歸藏出，而連山亡；周易成，而歸藏息；時之既易，易亦隨之，由歷代之文物考之，則連歸可備參證；若以時之宜，變之極，明易之道，為後世之則；則唯周易足與伏羲表裡，取周易而他易其中矣！此夫子以周易為輕，而博搜各易之義為傳也。

If we generalize, the Yijing of the Lianshan and Guicang schools are also considered Later Heaven, because they all explain the changes of Fuxi's Yijing, which is the same as the Zhou Yijing. The only difference is that when the Guicang appeared, the Lianshan disappeared; and when the Zhou Yijing was established, the Guicang ceased to exist. As times changed, the Yijing also changed. From historical relics, the Lianshan and Guicang can still serve as references. But if we consider which Yijing is most suitable for the times, fully explains the changes, and adequately demonstrates the principles of the Yijing to serve as a model for future generations, then only the Zhou Yijing corresponds with Fuxi's Yijing in both form and essence. Therefore, the Master took the Zhou Yijing as the main text and widely collected the meanings and interpretations from other schools to compose the "Commentaries."

周易之用，為救時明道，而本於易之原旨；易者以六爻三極，合天地人者也；天道陰陽，居上兩爻；地道剛柔，居下兩爻；人道仁義，居於中央；此名三極，以人道為綱。故三四爻，人之位，善惡之門，吉凶之途，皆在是焉；人為天地之中，道之所存，時之所依；教政所出，生化所成。

The purpose of The Zhou Changes is to correct current evils and clarify the great way, and its fundamental principle still comes from the original meaning of the Book of Changes. The term "Easy" refers to dividing the six lines into "three extremes," combining heaven, earth, and humanity into one. The heavenly way is yin and yang, located in the upper two lines; the earthly way is strength and softness, located in the lower two lines; the human way is benevolence and righteousness, located in the middle two lines. This is called "three extremes," with the human way as the main point. Therefore, the third line and the fourth line are the positions of human beings, where the gate of good and evil and the path of fortune and misfortune lie. Humans are situated in the middle of heaven and earth, which is the place where the way resides, the place where time relies upon, and also the source from which teachings and commands arise, and the origin from which life is nurtured and cultivated.

故天地之道，依人而明，時之敝，依人而新，教政之失，依人而復振；仁義之不講，時之亂也；教政之不明，人之責也；唯人能理亂救亡，正失止敝。故聖人則之，以負其任；而文王適逢之，乃明易之變，而濟道之窮；以教寓於象，而濟道之窮；以教寓於象，以心存於卦。

Therefore, the way of heaven and earth relies on people to be made clear, the corruption of the times depends on people to be renewed, and the mistakes in education and government depend on people to be restored. Not speaking of benevolence and righteousness is the disorder of the times; unclear education and government is the responsibility of people. Only people can rectify calamities, save from peril, correct mistakes, and prevent evils. Thus, sages emulate heaven and earth, taking up this responsibility. King Wen just happened to live in such an era, so he explained the changes of the Book of Changes, using it to relieve thepredicament of the Dao; he寄托 education in the hexagrams and placed his mind in the hexagram figures.

故其易與前異者，應夫時也。道之不明，時之所為；時之不回，則人心失所主，而變生焉；變之亂者，時之咎也；變之治者，人之功也；人應時而為變，變乃通，通乃道；故道在時，而聖人乃能用時；用時變時，是曰時中；道之存也，時之隆也，則守其常；道之晦也，時之汙也，則達其變；唯變乃復於中道，而道乃明。

Therefore, his Book of Changes differs from before, precisely to correspond with the times. The reason the Way is not clear is due to the times; if the times do not change, people's minds will lose their guidance, and chaos will arise. Chaos caused by change is due to the times; order achieved through change is due to human effort. When people adapt to the times and make changes, change leads to communication, and communication brings harmony with the Way. Therefore, the Way exists in the times, and only the sage can skillfully use the times. Being able to use the times and change the times is called "the middle of the times." When the Way still exists and the times are favorable, one should maintain the constant; when the Way is obscured and the times are corrupt, one should adapt and change. Only through adapting and changing can one return to the middle path, and the Way can be made clear.

聖人在因時明道，非守死而忘時也；乃因時而變之，以存亡正失也。故文王之易在於是，其意若曰：伏羲之易，經常之道，不可變也；時無明之者，易乃日晦；必以變而新之，則前者益光大；其義取在革卦，革以去故，言去時之汙也；而其用取之鼎卦，鼎取新也，言新易之道，而光大伏羲之制也。

The sage values adapting to the times in order to explain the great way, not rigidly adhering to old methods while ignoring the times. Instead, he follows the times to make changes, thus preserving what is about to perish and correcting what has already been lost. King Wen's approach to the Book of Changes is precisely this. His meaning seems to be that Fuxi's Book of Changes represents a constant way, which should not be altered. However, because at that time no one could explain it clearly, the principles of the Book of Changes gradually became obscured. Therefore, change was necessary to renew it, and the old methods became even more prominent. Hence, he drew the meaning from the "Revolution" hexagram, "Revolution" meaning removing the old, referring to eliminating the corruption of the times; and he used the "Tripod" hexagram, "Tripod" symbolizing renewal, referring to establishing new regulations for the Book of Changes, thus expanding upon Fuxi's original system.

故其序以往復循環為則，以吉凶相對，善惡相當；明世道之無往不復，而人心無時不動；必以善制惡，以新革故，以成循環之數，而復歸於道；此則文王之易所以異也。夫連、歸遞嬗，夏商異代；其政教不一，制度各殊，故文王因之；而鑑於二者，成其新作，存其所長；尤能揭二代之善制，合兩易之成規；以開有周之政教，為盡美盡善之禮樂制度；此夫子有從周之嘆也！

Therefore, the sequence of hexagrams in The Zhou Yi follows the principle of reciprocity and cyclical repetition, making good and bad relative to each other, and virtue and evil corresponding to one another, thereby demonstrating that the world's course has no irreversible direction, and human hearts never remain still for a moment. It is necessary to use virtue to overcome evil and to renew the old with the new, in order to fulfill the fixed destiny of the cycle, and thus return to the Dao. This is precisely what makes the Yi of King Wen different from others. The Lian Shan and Gui Zang came one after another, each representing a dynasty, with the political and educational systems of the Xia and Shang dynasties differing, and their institutions varying. King Wen inherited these, observed them critically, and composed his new Yi, preserving their strengths. Moreover, he was especially able to reveal the good laws of the Xia and Shang dynasties, blending the established practices of both Yi texts, to establish the political and educational systems of the Zhou dynasty, creating a perfect system of rites and music. This is why the Master expressed his lament, "I follow the Zhou."

故文王之易，為易道之大明；其旨在變，變以復道；乃宜於時之敝，道之衰，教之亡，政之失也；故夫子獨取之，以鑑於周道之微；春秋之亂，非重新易教，不克以復堯舜文王之道，而續伏羲神農黃帝之德也。其意見於雜卦焉，苟有明哲之主，而取用之；以新政教，振仁義；以盡人道，合乎天地之原旨；而因時推變，以孚革故鼎新之義；則文武之治，周初之禮樂制度，固當復見於世。

Therefore, King Wen's Book of Changes represents the great illumination of the Way of Change; its purpose is 'change,' which aims to return to the Dao. It is especially suitable for times of disorder, when the essence of the Dao is declining, moral teachings are lost, and political orders are disordered. Hence, the Master alone chose this Book of Changes, for he saw that the Zhou Way was declining and the Spring and Autumn period was chaotic. Without reviving the teachings of the Book of Changes, it would be impossible to restore the Way of Yao, Shun, and King Wen, and to continue the virtues of Fuxi, Shen Nong, and the Yellow Emperor. This meaning is expressed in the Miscellaneous Hexagrams. If a wise ruler were to adopt and apply it, using it to renew politics and education, to revive benevolence and righteousness, to fulfill human conduct, to align with the fundamental principles of heaven and earth, and to implement changes in accordance with the meaning of renewal and transformation, then the governance of King Wen and King Wu, and the rites and music of the early Zhou dynasty, could indeed be restored in the world.

則夫子老安少懷之志，大同之願，時中之智，皆將見於行事，非復微言之擬，文章之可知而已；觀夫《雜卦傳》末云：「君子道長，小人道消。」云云，蓋已自言其效，或者他日必驗於世；時乎時乎，吾知之矣！運之流行，寧無極乎！請留吾言，以待後人之證之也。

Then the Master's aspiration of "the elderly may be given peace, the young may be cherished," his wish for universal harmony, and his wisdom of maintaining balance at all times will be realized in actual deeds, no longer merely as comparisons in subtle words or things that can only be inferred from writings. Looking at the closing remarks of the "Zagua Transmission" which say "the way of the gentleman prevails, the way of the petty person declines," we can see that the Master himself has already spoken of the manifestation of these truths. Perhaps one day they will surely come to pass in the world. Oh, the times! I am fully aware! How could the flow of destiny have no end? Let me leave these words for future generations to verify.