此承上编阴阳应象，而复论阴阳之离合也。应象者，阴阳之征乎外也；离合者，阴阳之本乎内也。阴
阳之理，本于太极，由阴而阳，故曰阴阳。离则有三，合则为一，从三而十百千万皆离也；三阳归于一阳，
三阴归于一阴，皆合也。开阖枢者，开则为阳，阖则为阴，舍合则不能为开，舍开则不能为阖，是阴
阳互见，开阖并呈也。其曰阴之绝阳，是纯阴无阳而归于太极也，又曰阴之绝阴，是纯阴无阴，而归于
无极也。阴阳之理，从无极而太极，太极而阴阳，所以申明阴阳之离合者如此。
黄帝问曰∶余闻天为阳，地为阴，日为阳，月为阴，大小月三百六十日，成一岁，人亦应
之。今三阴三阳，不应阴阳，其故何也？
帝承上编阴阳应象之意，问天地日月阴阳营运，以成一岁，人之阴阳，亦与相应。今人身三阴三阳，
有不应天地日月阴阳之处，其故何也？帝承阴阳应象之意，而探阴阳之根本也。
岐伯对曰∶阴阳者，数之可十，推之可百，数之可千，推之可万，万之大，不可胜数，然其要一也。
数，上声；下可数，同胜，平声。自阴阳之应乎外者言之，则数之可十，推之可百，数之可千，推
之可万，至于万之大，尤不可
胜数，然探其本原，则有要道，其要归于一也。
天复地载，万物方生，未出地者，命曰阴处，名曰阴中之阴；则出地者，命曰阴中之阳。
试以天地万物言之，天复于上，地载于下，而万物方生。其万物之未出地者，命曰阴处，名曰阴中
之阴。夫未出地而名为阴中之阴，则出地者，当命曰阴中之阳。
阳予之正，阴为之主。故生因春，长因夏，收因秋，藏因冬，失常则天地四塞。
予，与同。长，上声。藏，如字。万物出乎阳，其体各正，是其正也，乃阳予之。万物主乎阴，其
性始成，是其主也，乃阴为之。阳正于外，阴主于内，四时行焉，百物生焉。故生因春，长因夏，
收因秋，藏因冬，此天地阴阳收藏之常。若失常，则天地四塞，天地四塞，则复载无从，而万物不生。
阴阳之变，其在人者，亦数之可数。
天地万物之阴阳，其变无穷，人身之阴阳，其变无穷，故阴阳之变，其在人者，亦不啻十百千万，
数之可数，所以申明阴阳之至大，而为离者如此。
帝曰∶愿闻三阴三阳之离合也。
三阴三阳，有离则有合，愿闻三阴三阳之离合，仍欲详明不应阴阳之义。
岐伯曰∶圣人南面而立，前曰广明，后曰太冲，太冲之地，名曰少阴，少阴之上，名曰太
阳。太阳根起于至阴，结于命门，名曰阴中之阳。
阳根于阴，三阳根于三阴，圣人南面而立，前曰广明，阳也，后曰太冲，阴也，故太冲之地，名曰
少阴，少阴之上，名曰太阳，是太阳之根于少阴也。故人身太阳之根，起于足小趾外侧之至阴，
结于目中央之命门，是虽太阳，而名曰阴中之阳，此太阳之根于少阴者如此。
中身而上，名曰广明，广明之下，名曰太阴，太阴之前，名曰
阳明，阳明根起于厉兑，名曰阴中之阳。
身半以上为阳，身半以下为阴。故中身而上，亦名曰广明，阳也，广明之下，名曰太阴，阴也，太阴之
前，名曰阳明，是阳明之根于太阴也。故人身阳明之根，起于足大趾次趾之厉兑，是虽阳
明，而名曰阴中之阳。此阳明之根于太阴者如此。
厥阴之表，名曰少阳，少阳根起于窍阴，名曰阴中之少阳。
少阳根于厥阴，故厥阴之表名曰少阳，人身少阳之根，起于足小趾、次趾之窍阴，是虽少阳，而名曰阴中
之少阳。夫太阳根于少阴，则曰少阴之上；阳明根于太阴，则曰太阴之前；少阳根于厥阴，则曰厥阴之表，
以明上下前后表里，其义一也。
是故三阳之离合也，太阳为开，阳明为阖，少阳为枢，三经者不得相失也，抟而弗浮，名曰一阳。
抟，音团，余篇同。论三阳之离合，自其离者而言之，太阳为开，阳明为阖，少阳为枢，自其离而复
合者言之，舍阖则不能开，舍开则不能为阖，舍开阖，则不能为枢。是三经者不得相失也。若
不开不阖不枢，抟聚凝一而弗浮，但命曰一阳。所以申明三阳之至微，而为合者如此。
帝曰∶愿闻三阴。
承上文三阳之意，而复愿闻三阴，
岐伯曰∶外者为阳，内者为阴。
知阳者知阴，知阴者知阳。外者为阳，如南面而立，前曰广明，中身而上，名曰广明者是也；内者为阴，
如后曰太冲，广明之下，名曰太阴者是也。
然则中为阴，其冲在下，名曰太阴。太阴根起于隐白，名曰阴中之阴。
由外阳内阴之义而推论之，然则中为阴，中亦内也，太阴坤土在内，而居中也。冲，太冲也。其冲在下
者，太冲属少阴，在太阴之下，而其中则名曰太阴。故人身太阴经穴之根，起于足大趾之隐
白，名曰阴中之阴，所以申明三阴之太阴也。
太阴之后名曰少阴，少阴根起于涌泉，名曰阴中之少阴。
其冲在下，故太阴之后，名曰少阴。人身少阴经穴之根，起于足心之涌泉，名曰阴中之少阴，
所以申明三阴之少阴也。
少阴之前，名曰厥阴，厥阴根起于大敦，阴之绝阳，名曰阴之绝阴。
太阴主开，厥阴主阖，少阴主枢，有开阖，而始有枢。是先厥阴而后少阴，故少阴之前，名曰厥阴。
人身厥阴经穴之根，起于足大趾三毛之大敦。厥阴为阴之尽，而曰阴之绝阳，言纯阴而绝无阳
也。名曰阴之绝阴，言纯阴而绝无阴也，绝阳绝阴，是太极而归于无极，所以申明三阴之厥阴也。
是故三阴之离合也，太阴为开，厥阴为阖，少阴为枢。三经者，
不得相失也。抟而弗沉，命曰一阴。
若夫三阴之离合也，离则太阴为开，厥阴的阖，少阴为枢。离而复合，是三经者开阖相资，枢转
相济，不得相失也。若不开不阖不枢，抟聚凝一而弗沉，命曰一阴，所以申明三阴之至微，而为合者如此。
阴阳HT HT ，积传为一周，气里形表，而为相成也。
HT ，冲同。合上文三阳三阴而并论之，人身阴阳冲冲，冲冲，往来不绝也。积传为一周，谓一周十
二时，漏水下百刻，二刻一小周，积传至百刻，则为日夜之一周也。气里形表，谓阴阳之气行于里，
阴阳之形立于表，表里形气，互相资益，而为阴阳离合之相成也。
这段文字承接上文《阴阳应象大论》的内容，进一步论述阴阳的分离与聚合。所谓“应象”，是指阴阳在体外的表现；所谓“离合”，是指阴阳在体内的根本状态。阴阳的道理，源于太极，由阴转化为阳，所以称为阴阳。分离时可以分为三（指三阴三阳），聚合时则归为一，从三扩展到十、百、千、万都是分离的状态；三阳回归于一阳，三阴回归于一阴，这都是聚合的状态。“开、阖、枢”中，开属于阳，阖属于阴，如果没有聚合的基础就不能实现开，如果没有开的功能就不能实现阖，这说明阴阳相互依存，开与阖同时呈现。文中所说的“阴之绝阳”，是指纯阴无阳而回归于太极；又说“阴之绝阴”，是指纯阴无阴（此处指阴阳界限消融）而回归于无极。阴阳的道理，是从无极到太极，再从太极到阴阳，正是为了阐明阴阳离合的道理。
黄帝问道：我听说天为阳，地为阴，日为阳，月为阴，大小月共三百六十日构成一年，人体也与之相应。现在人体的三阴三阳，似乎不与天地日月阴阳之数相符合，这是什么原因呢？
黄帝承接上文《阴阳应象大论》的意思，询问天地日月阴阳的运行如何构成一年，以及人体的阴阳是否与之相应。如今人身上的三阴三阳，有不符合天地日月阴阳规律的地方，其中的缘故是什么呢？黄帝继承《阴阳应象》之意，旨在探究阴阳的根本。
岐伯回答说：阴阳这个概念，推演起来可以分成十个，再推演可以变成一百，数下去可以到一千，再推演可以到一万，即使达到一万的程度，也无法穷尽，但其关键要点只有一个。
（注：“数”读上声；“下可数”中的“数”同“胜”，读平声。）从阴阳在体外的表现来说，数量可以推到十、百、千、万，甚至更多，不可胜数，但探求其本源，有一条重要的道理，其最终归结为一个要点。
天覆盖在上，地承载在下，万物开始生长。尚未破土而出的，被称为处于阴位，名叫阴中之阴；已经破土而出的，被称为阴中之阳。
试着以天地万物来比喻，天在上覆盖，地在下承载，万物正在萌发。那些尚未出地面的万物，被称为处于阴位，名叫阴中之阴。既然未出地面被称为阴中之阴，那么出地面的，就应当被称为阴中之阳。
阳气赋予万物端正的形体，阴气主宰万物的本性。因此，生长依靠春天，成长依靠夏天，收获依靠秋天，闭藏依靠冬天。如果违背了这个常理，天地四方的气机就会闭塞不通。
予，通“与”。长，读上声。藏，按字面读音。万物出于阳，其形体各自端正，这就是阳气所赋予的“正”；万物主于阴，其性质开始形成，这就是阴气所起到的“主”的作用。阳在外端正形体，阴在内主宰本性，四季运行，百物生长。所以生长因春，成长因夏，收获因秋，闭藏因冬，这是天地阴阳收藏的常规。如果违背了常规，天地四方之气就会闭塞，天地无法覆载，万物也就无法生存。
阴阳的变化，体现在人体身上，也是可以计数的。
天地万物的阴阳变化无穷无尽，人体的阴阳变化也是无穷无尽的，所以阴阳的变化，体现在人体身上的，也不止十、百、千、万，是可以计数的，这正是为了阐明阴阳至大无外，作为“离”的表现是如此。
黄帝说：我希望听听关于三阴三阳离合的道理。
三阴三阳，既有分离就有聚合，希望了解三阴三阳的离合，仍然是想要详细阐明它们看似不顺应天地阴阳数理的含义。
岐伯说：圣人面向南方站立，前面叫做广明，后面叫做太冲，太冲的部位，名叫少阴，少阴之上，名叫太阳。太阳经根起于至阴穴，结于命门，名叫阴中之阳。
阳根植于阴，三阳经根植于三阴经。圣人面向南方站立，前面是广明，属阳；后面是太冲，属阴。所以在太冲的部位，名叫少阴，少阴之上，名叫太阳，这说明太阳经根植于少阴经。所以人体太阳经的根部，起于足小趾外侧的至阴穴，结于眼睛中央的命门穴，虽然是太阳经，却名叫阴中之阳，这就是太阳经根植于少阴经的情况。
身体中部以上，名叫广明，广明之下，名叫太阴，太阴的前面，名叫阳明，阳明经根起于厉兑穴，名叫阴中之阳。
身半以上是阳，身半以下是阴。所以身体中部以上，也名叫广明，属阳；广明之下，名叫太阴，属阴；太阴的前面，名叫阳明，这说明阳明经根植于太阴经。所以人体阳明经的根部，起于足大趾和第二趾之间的厉兑穴，虽然是阳明经，却名叫阴中之阳。这就是阳明经根植于太阴经的情况。
厥阴的表层，名叫少阳，少阳经根起于窍阴穴，名叫阴中之少阳。
少阳经根植于厥阴经，所以厥阴的表层名叫少阳。人体少阳经的根部，起于足小趾和第二趾之间的窍阴穴，虽然是少阳经，却名叫阴中之少阳。太阳经根植于少阴经，所以说“少阴之上”；阳明经根植于太阴经，所以说“太阴之前”；少阳经根植于厥阴经，所以说“厥阴之表”，以此说明上下、前后、表里的关系，其义理是一致的。
因此，三阳经的离合关系中，太阳为开，阳明为阖，少阳为枢，这三条经脉不能相互脱离。它们凝聚而不浮散，统称为一阳。
（注：“抟”音团，其他篇章相同。）论述三阳经的离合，从其分离的角度来说，太阳为开，阳明为阖，少阳为枢；从其分离后又聚合的角度来说，没有阖就不能开，没有开就不能阖，没有开和阖，就不能成为枢。这三条经脉不能相互脱离。如果不开、不阖、不枢，而是凝聚合一且不浮散，就称之为“一阳”。这正是为了阐明三阳经的精微之处，作为“合”的表现是如此。
黄帝说：我希望听听关于三阴经的情况。
承接上文关于三阳经的意思，进而希望了解三阴经。
岐伯说：外部属阳，内部属阴。
知道阳就知道阴，知道阴就知道阳。外部属阳，就像面向南方站立，前面叫广明，身体中部以上叫广明，就是这种情况；内部属阴，就像后面叫太冲，广明之下叫太阴，就是这种情况。
然而中间部位属阴，其冲脉在下部，名叫太阴。太阴经根起于隐白穴，名叫阴中之阴。
由外阳内阴的道理推导，中间部位属阴，中也就是内。太阴属坤土，位于内部且居中。冲，指太冲。其冲脉在下部的，太冲属少阴，在太阴之下，而其中心部位名叫太阴。所以人体太阴经穴的根部，起于足大趾的隐白穴，名叫阴中之阴，这是为了阐明三阴经中的太阴经。
太阴的后面名叫少阴，少阴经根起于涌泉穴，名叫阴中之少阴。
因为冲脉在下部，所以在太阴的后面，名叫少阴。人体少阴经穴的根部，起于足心的涌泉穴，名叫阴中之少阴，这是为了阐明三阴经中的少阴经。
少阴的前面名叫厥阴，厥阴经根起于大敦穴，是阴之绝阳，名叫阴之绝阴。
太阴主开，厥阴主阖，少阴主枢，有了开和阖，才产生枢。所以先有厥阴后有少阴，因此在少阴的前面，名叫厥阴。人体厥阴经穴的根部，起于足大趾指甲边缘的大敦穴。厥阴是阴气的尽头，所以称为“阴之绝阳”，意思是纯阴而绝无阳。名叫“阴之绝阴”，意思是纯阴而绝无阴（指阴阳界限消失）。绝阳绝阴，意味着回归太极进而归于无极，这是为了阐明三阴经中的厥阴经。
因此，三阴经的离合关系中，太阴为开，厥阴为阖，少阴为枢。这三条经脉不能相互脱离。它们凝聚而不沉陷，统称为一阴。
至于三阴经的离合，分离时太阴为开，厥阴为阖，少阴为枢。分离后重新聚合，这三条经脉的开、阖、枢相互资助，相互补充，不能相互脱离。如果不开、不阖、不枢，而是凝聚合一且不沉陷，就称之为“一阴”，这是为了阐明三阴经的精微之处，作为“合”的表现是如此。
阴阳之气循环往复，积聚传递完成一个周期，气行于里，形立于表，从而相互成就。
（注：“HT”即“冲冲”，通“冲”。）结合上文三阳三阴一起论述，人体内的阴阳之气冲冲流动，往来不绝。积聚传递完成一个周期，指的是一周十二个时辰，漏壶滴水一百刻，两刻为一个小周期，积聚传递到一百刻，就是一昼夜的一个周期。气行于体内，形立于体表，表里的形和气互相资助，从而成就了阴阳的离合关系。
This passage continues from the previous section on *Yin Yang Ying Xiang* (Correspondence of Yin and Yang) to further discuss the separation and union of Yin and Yang. "Ying Xiang" refers to the manifestation of Yin and Yang externally; "Li He" (Separation and Union) refers to their fundamental state internally. The principle of Yin and Yang originates from Taiji (Supreme Ultimate), transforming from Yin to Yang, hence called Yin and Yang. When separated, they divide into three (referring to the Three Yin and Three Yang meridians); when united, they return to one. Extending from three to ten, hundred, thousand, and myriad represents separation; returning Three Yang to One Yang and Three Yin to One Yin represents union. In terms of Kai (Opening), He (Closing), and Shu (Pivot), Opening belongs to Yang, Closing belongs to Yin. Without union, there can be no opening; without opening, there can be no closing. This shows that Yin and Yang are mutually dependent, and Opening and Closing present simultaneously. The phrase "Yin's absolute Yang" refers to pure Yin without Yang, returning to Taiji. It is also said "Yin's absolute Yin," referring to a state where Yin boundaries dissolve, returning to Wuji (Non-Ultimate). The principle of Yin and Yang proceeds from Wuji to Taiji, and from Taiji to Yin and Yang, thereby elucidating the separation and union of Yin and Yang.
The Yellow Emperor asked: I have heard that Heaven is Yang, Earth is Yin, the Sun is Yang, and the Moon is Yin. The combination of large and small months totals 360 days, forming one year, and the human body corresponds to this. Now, the Three Yin and Three Yang in the human body seem not to correspond to the Yin and Yang of Heaven and Earth. What is the reason for this?
The Yellow Emperor, following the intent of *Yin Yang Ying Xiang*, inquired about how the movement and operation of Yin and Yang of Heaven, Earth, Sun, and Moon constitute a year, and whether human Yin and Yang correspond accordingly. Currently, the Three Yin and Three Yang in the human body have aspects that do not align with the Yin and Yang of Heaven and Earth. What is the cause? The Yellow Emperor, inheriting the meaning of *Yin Yang Ying Xiang*, seeks to explore the root of Yin and Yang.
Qi Bo replied: Yin and Yang, when counted, can be divided into ten; when deduced, into a hundred; counted further, into a thousand; deduced further, into ten thousand. Even reaching the magnitude of ten thousand, they cannot be fully enumerated, yet their essence remains one.
(Note: "Shu" (count) is pronounced with the rising tone; "Ke Shu" (can be counted) uses "Shu" synonymous with "Sheng" (overcome/exhaust), pronounced with the level tone.) Speaking from the external manifestations of Yin and Yang, numbers can extend to ten, hundred, thousand, and myriad, becoming incalculable. However, exploring their origin reveals a key principle, ultimately归结ing to one point.
Heaven covers above, Earth supports below, and all things begin to grow. Those not yet emerging from the earth are designated as being in a Yin position, named Yin within Yin; those that have emerged from the earth are named Yin within Yang.
Let us use the example of Heaven, Earth, and all things. Heaven covers above, Earth supports below, and all things are sprouting. All things not yet out of the ground are designated as being in a Yin position, named Yin within Yin. Since those not out of the ground are called Yin within Yin, those that emerge should be called Yin within Yang.
Yang provides the correct form, while Yin serves as the master. Therefore, growth depends on Spring, development depends on Summer, harvest depends on Autumn, and storage depends on Winter. If this regularity is violated, the Qi of the four directions of Heaven and Earth will become blocked.
"Yu" is synonymous with "Yu" (give). "Zhang" (grow) is pronounced with the rising tone. "Cang" (store) is pronounced as written. All things emerge from Yang, and their forms are rectified; this rectification is provided by Yang. All things are governed by Yin, and their natures begin to form; this governance is performed by Yin. Yang rectifies externally, Yin governs internally. The four seasons proceed, and all things grow. Thus, growth is due to Spring, development to Summer, harvest to Autumn, and storage to Winter. This is the normal pattern of Yin and Yang storage in Heaven and Earth. If this norm is violated, the Qi of Heaven and Earth will block up. If Heaven and Earth are blocked, covering and supporting will cease, and all things will not be born.
The changes of Yin and Yang, as manifested in humans, are also countable.
The Yin and Yang of Heaven and Earth change infinitely, and the Yin and Yang of the human body also change infinitely. Therefore, the changes of Yin and Yang in humans are not limited to ten, hundred, thousand, or myriad; they are countable. This clarifies that Yin and Yang are vast and boundless, representing the aspect of "separation."
The Yellow Emperor said: I wish to hear about the separation and union of the Three Yin and Three Yang.
The Three Yin and Three Yang involve both separation and union. Wishing to understand their separation and union is still to clarify why they seemingly do not conform to the Yin and Yang of Heaven and Earth.
Qi Bo said: When a sage stands facing South, the front is called Guang Ming (Broad Brightness), and the back is called Tai Chong (Great Surge). The area of Tai Chong is named Shao Yin (Lesser Yin), and above Shao Yin is named Tai Yang (Greater Yang). The Tai Yang meridian originates at Zhi Yin (Reaching Yin) acupoint and terminates at Ming Men (Gate of Life), named Yang within Yin.
Yang is rooted in Yin, and the Three Yang meridians are rooted in the Three Yin meridians. When a sage stands facing South, the front is Guang Ming, which is Yang; the back is Tai Chong, which is Yin. Thus, the area of Tai Chong is named Shao Yin, and above Shao Yin is Tai Yang, indicating that Tai Yang is rooted in Shao Yin. Therefore, the root of the human Tai Yang meridian begins at Zhi Yin on the lateral side of the fifth toe and terminates at Ming Men in the center of the eye. Although it is Tai Yang, it is named Yang within Yin. This illustrates how Tai Yang is rooted in Shao Yin.
The upper part of the torso is called Guang Ming. Below Guang Ming is named Tai Yin (Greater Yin). In front of Tai Yin is named Yang Ming (Bright Yang). The Yang Ming meridian originates at Li Dui (Marsh Meeting) acupoint, named Yang within Yin.
The upper half of the body is Yang, and the lower half is Yin. Thus, the upper torso is also called Guang Ming, which is Yang. Below Guang Ming is Tai Yin, which is Yin. In front of Tai Yin is Yang Ming, indicating that Yang Ming is rooted in Tai Yin. Therefore, the root of the human Yang Ming meridian begins at Li Dui between the first and second toes. Although it is Yang Ming, it is named Yang within Yin. This illustrates how Yang Ming is rooted in Tai Yin.
The exterior of Jue Yin (Terminal Yin) is named Shao Yang (Lesser Yang). The Shao Yang meridian originates at Qiao Yin (Aperture Yin) acupoint, named Lesser Yang within Yin.
Shao Yang is rooted in Jue Yin, so the exterior of Jue Yin is named Shao Yang. The root of the human Shao Yang meridian begins at Qiao Yin between the fourth and fifth toes. Although it is Shao Yang, it is named Lesser Yang within Yin. Tai Yang is rooted in Shao Yin, hence "above Shao Yin"; Yang Ming is rooted in Tai Yin, hence "in front of Tai Yin"; Shao Yang is rooted in Jue Yin, hence "the exterior of Jue Yin." This clarifies the relationships of upper/lower, front/back, and interior/exterior, sharing the same principle.
Therefore, in the separation and union of the Three Yang meridians, Tai Yang is Kai (Opening), Yang Ming is He (Closing), and Shao Yang is Shu (Pivot). These three meridians must not lose connection with each other. They gather and do not float, collectively named One Yang.
(Note: "Tuan" is pronounced like "tuan" (gather), same in other chapters.) Discussing the separation and union of the Three Yang meridians, from the perspective of separation: Tai Yang is Opening, Yang Ming is Closing, Shao Yang is Pivot. From the perspective of re-union: without Closing, there can be no Opening; without Opening, there can be no Closing; without Opening and Closing, there can be no Pivot. These three meridians must not be disconnected. If there is no Opening, Closing, or Pivot, but rather they gather into one unity without floating, it is called "One Yang." This elucidates the subtlety of the Three Yang meridians as "union."
The Yellow Emperor said: I wish to hear about the Three Yin.
Following the discussion on the Three Yang, he now wishes to hear about the Three Yin.
Qi Bo said: The exterior is Yang, and the interior is Yin.
To know Yang is to know Yin, and to know Yin is to know Yang. The exterior is Yang, such as standing facing South, where the front is Guang Ming, and the upper torso is Guang Ming. The interior is Yin, such as the back being Tai Chong, and below Guang Ming being Tai Yin.
However, the middle region is Yin. Its Tai Chong is located below, named Tai Yin. The Tai Yin meridian originates at Yin Bai (Hidden White) acupoint, named Yin within Yin.
Deducing from the principle that the exterior is Yang and the interior is Yin, the middle region is Yin, and the middle is also interior. Tai Yin belongs to Kun Earth, located in the interior and centered. "Chong" refers to Tai Chong. The Tai Chong belonging to Shao Yin is below Tai Yin, and its central part is named Tai Yin. Therefore, the root of the human Tai Yin meridian acupoints begins at Yin Bai on the big toe, named Yin within Yin. This elucidates Tai Yin among the Three Yin.
Behind Tai Yin is named Shao Yin. The Shao Yin meridian originates at Yong Quan (Gushing Spring) acupoint, named Lesser Yin within Yin.
Since the Chong is below, behind Tai Yin is named Shao Yin. The root of the human Shao Yin meridian acupoints begins at Yong Quan in the sole of the foot, named Lesser Yin within Yin. This elucidates Shao Yin among the Three Yin.
In front of Shao Yin is named Jue Yin. The Jue Yin meridian originates at Da Dun (Great Mound) acupoint. It is the absolute Yin of Yang, named the absolute Yin of Yin.
Tai Yin governs Opening, Jue Yin governs Closing, and Shao Yin governs Pivot. With Opening and Closing, there arises the Pivot. Thus, Jue Yin comes before Shao Yin, so in front of Shao Yin is named Jue Yin. The root of the human Jue Yin meridian acupoints begins at Da Dun at the hairline of the big toe. Jue Yin is the end of Yin, hence called "Absolute Yin of Yang," meaning pure Yin without any Yang. Named "Absolute Yin of Yin," it means pure Yin without any Yin (boundaries dissolved). Absolute Yang and Absolute Yin imply returning to Taiji and then to Wuji. This elucidates Jue Yin among the Three Yin.
Therefore, in the separation and union of the Three Yin meridians, Tai Yin is Kai (Opening), Jue Yin is He (Closing), and Shao Yin is Shu (Pivot). These three meridians must not lose connection with each other. They gather and do not sink, collectively named One Yin.
Regarding the separation and union of the Three Yin meridians, upon separation, Tai Yin is Opening, Jue Yin is Closing, and Shao Yin is Pivot. Upon re-union, the Opening, Closing, and Pivot of these three meridians support and assist each other, never disconnecting. If there is no Opening, Closing, or Pivot, but rather they gather into one unity without sinking, it is called "One Yin." This elucidates the subtlety of the Three Yin meridians as "union."
Yin and Yang circulate continuously, accumulating and transmitting to complete one cycle. Qi resides in the interior, Form stands in the exterior, and they mutually accomplish each other.
(Note: "HT" represents "Chong Chong," synonymous with "Chong" (surge/pulse).) Combining the discussion of the Three Yang and Three Yin, the Yin and Yang Qi in the human body surge continuously, flowing without cessation. Accumulating and transmitting to complete one cycle refers to one full day-night cycle of twelve double-hours, measured by 100 water-clock units. Two units constitute a small cycle; accumulating to 100 units constitutes one full cycle of day and night. Qi moves in the interior, Form stands in the exterior. Interior and exterior, Form and Qi, mutually support each other, thereby accomplishing the separation and union of Yin and Yang.