阴阳除了上面的这些关系外还可以从体用的角度来谈，体用是传统文化里一个重要的概念。体是谈基础，用是谈作用，谈应用。没有体，这个用不可能发生，而没有用的体，那这个体也就从根本上失去了意义。上面这个体用的关系怎么说明阴阳呢？具体地说，阴阳之间，哪一个属体？哪一个属用？很显然，如果我们把阴阳看作一个整体，那么，反映用的主要是阳，反映体的主要是阴。在《中基》里，当谈到肝的功能时，有一个体阴用阳的概念，实际上，不但肝如此，整个阴阳都是如此。我们从一年来看，春夏为阳，秋冬为阴。这个春夏的过程主要就体现了阳的作用，我们看春夏的阳光，看春夏的温热，看春夏的繁荣，这一切都反映了阳气在积极发挥作用。所以，春夏为阳，这个阳是讲用，这个问题不难理解。这与前面讲的释放状态相应。那么，秋冬呢？秋冬这样一个寒冷的、凋零的景象，显然与阳的作用不符。为什么呢？因为阳用收藏起来了，你看不见了，所以，你见到的是另外一番景象。这就关系到体的问题。体是基础，体是本钱。而秋冬的阴，秋冬的收藏，正是为了培植这个基础，蓄积这个本钱。基础巩固了，本钱增加了，上述这个用才能更好的发挥。因此，从这个角度来看，体与用，阴与阳一点不相违。两者相辅相成，互根互用。缺一不可。阳的用这一面，我们很容易感受到，但是，我们也不能因为前面对阳的强调而忽视了这个体的意义。应该知道，它与强调阳用并不矛盾。所以，光强调男权不行，还要谈女权。现在不是有一句流行的语言，“每个成功男人的背后，都有一个成功的女人”吗？这句话讲得很实在，很多情况确实是这样。只是现在很多男人成功之后，就把原来助他的女人抛弃了，这个不但不道德，而且很愚蠢，将来注定他要遭挫折。阳讲用，这个用可以反映在很多方面。首先一个就是阳生阴长，这个化气的阳，能够促成万物的生长。春夏的景象为什么发陈？为什么蕃秀？就是因为这个因素。第二个用，阳为寿命之根本，《素问·生气通天论》讲：“阳气者，若天与日，失其所则折寿而不彰。”因此，阳用很重要的一个方面就反映在它与寿命的关系，人的寿夭就要落实在这个阳气上面。长寿的人阳气没有不充足，相反，若阳失其所，则有折寿短命之虞。第三，“阳者，卫外而为固”，这也是阳用非常重要的一个方面。我们这个身体牢不牢固，能不能抵御外邪的侵袭，就要看这个阳的卫外作用。这个作用与健康的关系很大。我们说人身最大的问题除了事业以外，就是一个健康，一个长寿，而阳用就反映在这个上面。阴讲体，这个体的意义表现在什么地方呢？比如一个家庭，尤其是过去的家庭，妇女只会生儿育女，操持家务，怎么来体现女人的作用呢？就看你这个男的有没有出息。男的搞得好，说明你家的内助不错。为什么叫内助？帮助的意思，助阳的意思。也就是说，阴的意义主要体现在助阳方面，怎么帮助阳去发挥应有的作用，这个就是阴体的意义。阴为阳体，阳为阴用。“阳在外，阴之使也，阴在内阳之守也”，两者就是这么一种关系。阴为体，它的一个很突出的方面就是它的藏精作用。《素问·生气通天论》云：“阴者，藏精而起亟也；阳者，卫外而为固也。”什么叫“精”？实际上，精既不是阴，也不是阳。现在很多人在概念上搞混淆了，把上面这个精作阴来看，所以，习惯就称阴精。如果精就是阴，那这个藏精怎么讲，它还怎么藏精？这从逻辑上讲不通。从严格的意义上说，“精”实际上指的是阳气的蓄积状态，能量的蓄积状态就叫“精”。某样东西暴发的能量越大，说明它阳气的蓄积状态越好。当然，在《内经》里，在《中基》里，精还有许多其他的解释，我这里是从最基本的义理上去分析。精是阳气的聚集态，而不是释放态。而阴的藏精就体现在帮助这个聚集的过程。阳气能不能聚集？能不能由释放状态转入蓄积状态？就靠这个阴的作用。那么，具体地说，这个精藏于何处呢？《素问·六节藏象论》说：“肾者主蛰，封藏之本，精之处也。”蛰是藏伏的意思，肾是主藏的，所以，又称作封藏之本。封藏什么呢？封藏阳气，封藏精。这个精，这个聚集态的阳气就被封藏在肾的领地里。所以说“精之处也”。肾在一年里属冬，冬主藏；肾在五藏属阴，属阴中之阴。这就与上面这个阴体，上面这个藏精相应了。所以，上面的这个体，上面这个阳气的蓄养过程，在很大程度上要落实在这个肾上。精能否封藏好？阳气能否得到充分的蓄藏，休养生息？就要看这个肾的功能。只有蓄养好了，释放才好，精力才会旺盛。所以，人的精力如何，很重要的方面就是看肾。阴讲体的这一面清楚了，体的目的是为了帮助用，这样人们就不会再把阴阳的关系对立起来。应该从统一中去看对立，而不应该像过去那样，由对立看对立。阴阳的体用关系，我们还可以从生活的许多方面去感受。比如说休息，过去我们对休息的理解也许比较笼统，以为坐下来就是休息，睡觉就是休息。其实，细分起来，它仍然是谈的两个方面。上面这个笼统的方面实际上包含在“休”字里，休就是指的这个过程。休者休心也，停下手中的活小歇一下，叫做休，而停止一天的活动，上床睡觉更叫休。所以，休字从人从木，人躺在木床上是谓休。那么，休的目的是为了什么呢？这一点相信大家都很清楚。晚上睡觉是为了第二天有充沛的精力，午休的目的也如此。有午休习惯的人，突然哪一天不午休，那整个下午都会昏昏沉沉，打不起精神来。因此，休的这个作用就落实在“息”上。什么叫“息”呢？现在大家在银行里存钱，为的什么呢？为的就是这个“息”。早十年我们在银行存钱，年息是 9% 、8% ，也就是一万块钱一年下来，就变成了一万零九百元，增加了整整九百元。正是为了这年息 9% ，大家都愿意把钱存在银行里。因此，这个“息”就是增加的意思，通过存钱使利益增加了，所以叫利息。休息呢？很显然，就是通过这个休的过程，使我们在工作中消耗掉的精神体力得到增加，重新恢复精力充沛的状态。所以，休息也包含着体用两个方面，也包含着阴阳两个方面。春夏为阳，秋冬为阴，实际上是讲春夏为用，秋冬为体。用的发挥怎么样，在很大程度上要看这个体好不好。所以，春夏的用如何，就要落实在秋冬，尤其是冬这个体上。《素问·四气调神大论》云：“所以圣人春夏养阳，秋冬养阴，以从其根。”过去许多人对这个养阴养阳不理解，以为春夏养阳岂不是火上加油，秋冬养阴岂不是雪上加霜，《中医杂志》还专门就这个问题组织公开讨论。其实，我们从体用的角度看，这有什么疑问呢？春夏养阳就是促进用的发挥，秋冬养阴就是把体涵养得更好。这是从体用的角度来谈阴阳，大家尚可以引而伸之，推而广之。
2.伤寒总说
以上我们讲到了两个关系，一个主导，一个体用。阴阳的这些东西弄清以后，就可以解答上述的那三个问题。
（1）寒为冬气
首先，我们来看寒，寒是冬日的正气，这一点我们在《中基》里面已经学过。春温、夏热、秋凉、冬寒，怎么会产生寒呢？这一点我们前面已经提到过，阳的本性是属热的，春夏的阳气处于释放状态，热的东西散发出来了，所以，天气变得温热。但是，春天释放的程度要比夏天小，因此，春天的温度要比夏天低。到了秋冬，阳气由释放转入到收藏，热的东西收藏起来了，关闭起来了，天气也就变得渐渐地寒冷。但是从程度而言，秋天的收藏不及冬日，因此，冬日的气温更为寒冷。这是寒的一个根本意义。从这个意义我们可以看到，寒实际上是反映阳气的收藏状态，是阳气收藏的外在表现。所以，寒不但是冬之气，其实也是藏之气。现在我们暂且放下时间，来看一看空间方位的情况。在我们国家，大家都很清楚，西北的气温要较东南低得多，我们每年冬天看天气预报，北方有些地区都零下十几度了，南方还在零上二十多度。这个反差太大了，要是海南的人到北方出差，上飞机前穿衬衣，下飞机就要穿皮袄了。为什么会出现这样大的差别呢？看一看《内经》就清楚了。《素问·阴阳应象大论》说：“西北方阴也，东南方阳也。”阳就是用，就是释放，阴就是体，就是收藏。从地域方位的角度而言，整个西北方以收藏为主，整个东南方以释放为主，所以，就产生了这个气温上的悬殊。这就提示我们一个问题，学中医不但要注意时间，也要注意空间方位。时空在中医里是同一的，是统一的，这个观念必须牢牢记住。前面我们提出过，阴阳的问题要真正弄清，不能光停留在书本的那几点上，要有切身的感受。什么事情都要养成用阴阳来思维，比如我们生活在南宁的人，时间都快到春节了，身上却还穿着衬衣，这是为什么呢？如果我们不从阴阳这个角度去思考，去弄清它，那作为一个学中医的人，你就麻木了，就凭这个麻木，你要学好中医，我看没多少可能。
（2）何以养藏
除了上述关系外，阴阳还可以从“体用”的角度来探讨。“体用”是传统文化中的一个重要概念。“体”指基础，“用”指作用和应用。没有“体”，就不可能发生“用”；而没有“用”的“体”，从根本上就失去了意义。那么，如何用“体用”的关系来说明阴阳呢？具体来说，在阴阳之间，哪一方属“体”，哪一方属“用”？很明显，如果我们将阴阳视为一个整体，那么主要反映“用”的是阳，主要反映“体”的是阴。
在《中医基础理论》中，谈到肝脏的功能时，有一个“体阴用阳”的概念。实际上，不仅肝脏如此，整个阴阳关系都是如此。从一年来看，春夏属阳，秋冬属阴。春夏的过程主要体现了阳的作用。我们看春夏的阳光、温热和繁荣景象，这些都反映了阳气在积极发挥作用。因此，说“春夏为阳”，这个“阳”讲的是“用”，这一点不难理解。这与前面提到的“释放状态”相应。那么，秋冬呢？秋冬寒冷、凋零的景象，显然与阳的作用不符。为什么呢？因为阳的“用”收藏起来了，看不见，所以我们看到的是另一番景象。这就涉及到了“体”的问题。“体”是基础，是本钱。而秋冬的阴，以及秋冬的收藏，正是为了培植这个基础，蓄积这个本钱。基础巩固了，本钱增加了，上述的“用”才能更好地发挥。因此，从这个角度来看，“体”与“用”、“阴”与“阳”一点也不矛盾。两者相辅相成，互根互用，缺一不可。
对于阳的“用”这一面，我们很容易感受到，但我们不能因为前面强调了阳，就忽视了这个“体”的意义。应该知道，强调“体”与强调阳的“用”并不矛盾。所以，光强调男权不行，还要谈女权。现在不是有一句流行语吗：“每个成功男人的背后，都有一个成功的女人。”这句话讲得很实在，很多情况确实是这样。只是现在很多男人成功后，就把原来帮助他的女人抛弃了，这既不道德，也很愚蠢，将来注定要遭受挫折。
阳的“用”可以反映在很多方面。首先是“阳生阴长”，这种化气的阳，能够促成万物的生长。为什么春夏的景象是“发陈”（推陈出新）和“蕃秀”（繁茂秀丽）？就是因为有这个因素。第二个“用”，阳是寿命的根本。《素问·生气通天论》说：“阳气者，若天与日，失其所则折寿而不彰。”因此，阳的“用”很重要的一个方面就反映在它与人寿命的关系上，人的长寿或夭折都要落实在这个阳气上。长寿的人，阳气无不充足；相反，如果阳气失去其正常位置（功能失常），就有折寿短命的危险。第三，“阳者，卫外而为固”，这也是阳的“用”非常重要的一个方面。我们的身体是否牢固，能否抵御外邪侵袭，就要看这个阳的卫外作用。这个作用与健康关系很大。我们常说人身最大的问题除了事业以外，就是健康和长寿，而阳的“用”就反映在这上面。
阴讲“体”，这个“体”的意义表现在什么地方呢？比如一个家庭，尤其是过去的家庭，妇女只会生儿育女、操持家务，怎么来体现女人的作用呢？就看你这个男人有没有出息。男人搞得好，说明你家的内助不错。为什么叫“内助”？意思是帮助，即助阳的意思。也就是说，阴的意义主要体现在助阳方面，即如何帮助阳去发挥应有的作用，这就是阴作为“体”的意义。阴为阳之体，阳为阴之用。“阳在外，阴之使也；阴在内，阳之守也”，两者就是这么一种关系。
阴作为“体”，其一个很突出的方面就是它的“藏精”作用。《素问·生气通天论》云：“阴者，藏精而起亟也；阳者，卫外而为固也。”什么叫“精”？实际上，“精”既不是阴，也不是阳。现在很多人在概念上混淆了，把上面的“精”当作阴来看，所以习惯称“阴精”。如果“精”就是阴，那“藏精”怎么讲？它还怎么藏精？这在逻辑上讲不通。从严格的意义上说，“精”实际上指的是阳气的蓄积状态，能量的蓄积状态就叫“精”。某样东西爆发的能量越大，说明它阳气的蓄积状态越好。当然，在《内经》和《中医基础理论》中，“精”还有许多其他的解释，我这里是从最基本的义理上去分析。“精”是阳气的聚集态，而不是释放态。而阴的“藏精”就体现在帮助这个聚集的过程。阳气能不能聚集？能不能由释放状态转入蓄积状态？就靠这个阴的作用。
那么，具体地说，这个“精”藏于何处呢？《素问·六节藏象论》说：“肾者主蛰，封藏之本，精之处也。”“蛰”是藏伏的意思，肾主藏，所以又称作“封藏之本”。封藏什么呢？封藏阳气，封藏精。这个“精”，即这个聚集态的阳气，就被封藏在肾的领地（管辖范围）里。所以说“精之处也”。肾在一年里属冬，冬主藏；肾在五藏（五脏）属阴，属阴中之阴。这就与上面所说的阴作为“体”、以及藏精的功能相应了。所以，上面的这个“体”，即阳气的蓄养过程，在很大程度上要落实在这个肾上。精能否封藏好？阳气能否得到充分的蓄藏、休养生息？就要看肾的功能。只有蓄养好了，释放才好，精力才会旺盛。所以，人的精力如何，很重要的方面就是看肾。
清楚了阴讲“体”的这一面，就知道“体”的目的是为了帮助“用”，这样人们就不会再把阴阳的关系对立起来。应该从统一中去看待对立，而不应该像过去那样，仅由对立去看对立。
阴阳的体用关系，我们还可以从生活的许多方面去感受。比如说休息。过去我们对休息的理解也许比较笼统，以为坐下来就是休息，睡觉就是休息。其实，细分起来，它仍然是谈的两个方面。上面那个笼统的方面实际上包含在“休”字里，“休”就是指这个过程。“休者，休心也”，停下手中的活小歇一下，叫做“休”；而停止一天的活动，上床睡觉更叫“休”。所以，“休”字从人从木，人躺在木床上谓之“休”。那么，“休”的目的是为了什么呢？这一点相信大家都很清楚。晚上睡觉是为了第二天有充沛的精力，午休的目的也是如此。有午休习惯的人，突然哪一天不午休，那整个下午都会昏昏沉沉，打不起精神来。因此，“休”的这个作用就落实在“息”上。什么叫“息”呢？现在大家在银行里存钱，为的是什么？为的就是这个“息”。早十年我们在银行存钱，年息是9%、8%，也就是一万块钱一年下来，就变成了一万零九百元，增加了整整九百元。正是为了这年息9%，大家都愿意把钱存在银行里。因此，这个“息”就是增加的意思，通过存钱使利益增加了，所以叫利息。休息呢？很显然，就是通过这个“休”的过程，使我们在工作中消耗掉的精神体力得到增加，重新恢复精力充沛的状态。所以，休息也包含着“体用”两个方面，也包含着“阴阳”两个方面。
春夏为阳，秋冬为阴，实际上是讲春夏为“用”，秋冬为“体”。“用”的发挥怎么样，在很大程度上要看这个“体”好不好。所以，春夏的“用”如何，就要落实在秋冬，尤其是冬这个“体”上。《素问·四气调神大论》云：“所以圣人春夏养阳，秋冬养阴，以从其根。”过去许多人对这个“养阴养阳”不理解，以为春夏养阳岂不是火上加油，秋冬养阴岂不是雪上加霜，《中医杂志》还专门就这个问题组织公开讨论。其实，我们从体用的角度看，这有什么疑问呢？春夏养阳就是促进“用”的发挥，秋冬养阴就是把“体”涵养得更好。这是从体用的角度来谈阴阳，大家尚可以引而伸之，推而广之。
2. 伤寒总说
以上我们讲到了两个关系：一个是主导，一个是体用。阴阳的这些道理弄清以后，就可以解答上述的那三个问题。
（1）寒为冬气
首先，我们来看“寒”。“寒”是冬日的正气，这一点我们在《中医基础理论》里面已经学过。春温、夏热、秋凉、冬寒，怎么会产生“寒”呢？这一点我们前面已经提到过，阳的本性是属热的。春夏的阳气处于释放状态，热的东西散发出来了，所以天气变得温热。但是，春天释放的程度要比夏天小，因此春天的温度要比夏天低。到了秋冬，阳气由释放转入到收藏，热的东西收藏起来了，关闭起来了，天气也就渐渐地变得寒冷。但是从程度而言，秋天的收藏不及冬日，因此冬日的气温更为寒冷。这是“寒”的一个根本意义。从这个意义我们可以看到，“寒”实际上是反映阳气的收藏状态，是阳气收藏的外在表现。所以，“寒”不但是冬之气，其实也是“藏”之气。
现在我们暂且放下时间，来看一看空间方位的情况。在我们国家，大家都很清楚，西北的气温要较东南低得多。我们每年冬天看天气预报，北方有些地区都零下十几度了，南方还在零上二十多度。这个反差太大了，要是海南的人到北方出差，上飞机前穿衬衣，下飞机就要穿皮袄了。为什么会出现这样大的差别呢？看一看《内经》就清楚了。《素问·阴阳应象大论》说：“西北方阴也，东南方阳也。”阳就是用，就是释放；阴就是体，就是收藏。从地域方位的角度而言，整个西北方以收藏为主，整个东南方以释放为主，所以，就产生了这个气温上的悬殊。这就提示我们一个问题：学中医不但要注意时间，也要注意空间方位。时空在中医里是同一的，是统一的，这个观念必须牢牢记住。前面我们提出过，阴阳的问题要真正弄清，不能光停留在书本的那几点上，要有切身的感受。什么事情都要养成用阴阳来思维。比如我们生活在南宁的人，时间都快到春节了，身上却还穿着衬衣，这是为什么呢？如果我们不从阴阳这个角度去思考、去弄清它，那作为一个学中医的人，你就麻木了。就凭这个麻木，你要学好中医，我看没多少可能。
（2）何以养藏
In addition to the aforementioned relationships, Yin and Yang can also be discussed from the perspective of "Ti-Yong" (Substance-Function). "Ti-Yong" is an important concept in traditional culture. "Ti" refers to the foundation or substance, while "Yong" refers to function or application. Without Ti, Yong cannot occur; and without Yong, Ti fundamentally loses its meaning. So, how does the relationship between Ti and Yong explain Yin and Yang? Specifically, within Yin and Yang, which belongs to Ti and which to Yong? Obviously, if we view Yin and Yang as a whole, then Yang primarily reflects Yong (function), and Yin primarily reflects Ti (substance).
In *Basic Theory of Traditional Chinese Medicine* (*Zhongji*), when discussing the functions of the Liver, there is a concept of "Liver has Yin as its Ti and Yang as its Yong." In fact, not only the Liver is like this; the entire relationship between Yin and Yang follows this pattern. Looking at a year, Spring and Summer belong to Yang, while Autumn and Winter belong to Yin. The process of Spring and Summer mainly embodies the function of Yang. Observing the sunlight, warmth, and prosperity of Spring and Summer, all these reflect the active functioning of Yang Qi. Therefore, saying "Spring and Summer are Yang," this "Yang" speaks of Yong (function), which is not difficult to understand. This corresponds to the "release state" mentioned earlier. What about Autumn and Winter? The cold and withering scenes of Autumn and Winter obviously do not accord with the function of Yang. Why? Because the Yong (function) of Yang is stored away and invisible, so what you see is a different scene. This relates to the issue of Ti (substance). Ti is the foundation, the capital. The Yin of Autumn and Winter, and the storing/collecting nature of Autumn and Winter, are precisely for cultivating this foundation and accumulating this capital. Once the foundation is solidified and the capital increased, the aforementioned Yong (function) can be better exerted. Therefore, from this perspective, Ti and Yong, Yin and Yang are not contradictory at all. They complement each other, root in each other, and use each other. Neither can be missing.
We can easily perceive the Yong (function) aspect of Yang, but we must not ignore the significance of this Ti (substance) because of the previous emphasis on Yang. It should be understood that emphasizing Ti does not contradict emphasizing the Yong of Yang. Thus, it is insufficient to emphasize male power alone; one must also discuss female power. Is there not a popular saying now: "Behind every successful man stands a successful woman"? This statement is very practical, and indeed, many situations are like this. However, many men, after achieving success, abandon the women who helped them originally. This is not only immoral but also foolish, and he is destined to suffer setbacks in the future.
The Yong (function) of Yang can be reflected in many aspects. First is "Yang generates, Yin grows." This Yang Qi that transforms into Qi can promote the growth of all things. Why are the scenes of Spring and Summer described as "Fa Chen" (pushing out the old to make way for the new) and "Fan Xiu" (luxuriant and beautiful)? It is because of this factor. The second Yong (function): Yang is the root of longevity. *Suwen: Shengqi Tongtian Lun* states: "The Yang Qi of humans is like the sky and the sun; if it loses its proper place/function, lifespan will be shortened and brilliance diminished." Therefore, an important aspect of the Yong (function) of Yang is reflected in its relationship with lifespan; human longevity or premature death is grounded in this Yang Qi. Those who live long have abundant Yang Qi; conversely, if Yang Qi loses its proper place/function, there is the danger of shortened life. Third, "Yang protects the exterior and secures the interior," which is another very important aspect of the Yong (function) of Yang. Whether our body is firm and capable of resisting external pathogenic factors depends on this protective function of Yang. This function is closely related to health. We often say that apart from career, the biggest issues in human life are health and longevity, and the Yong (function) of Yang is reflected here.
When Yin speaks of Ti (substance), where is the significance of this Ti manifested? For example, in a family, especially in past times, women would only bear children and manage household chores. How is their role manifested? It depends on whether the man is successful. If the man does well, it indicates that his internal helper is excellent. Why is she called "Nei Zhu" (Internal Helper)? It means assistance, i.e., assisting Yang. That is to say, the significance of Yin is mainly embodied in assisting Yang—how to help Yang exert its due function. This is the significance of Yin as Ti (substance). Yin is the Ti of Yang, and Yang is the Yong of Yin. "Yang is outside, the envoy of Yin; Yin is inside, the guardian of Yang." This is the relationship between the two.
As Ti (substance), one prominent aspect of Yin is its function of "storing Jing (Essence)." *Suwen: Shengqi Tongtian Lun* says: "Yin stores Jing and rises urgently; Yang protects the exterior and secures the interior." What is meant by "Jing"? Actually, Jing is neither Yin nor Yang. Many people confuse concepts nowadays, viewing the aforementioned Jing as Yin, hence the habitual term "Yin Jing" (Yin Essence). If Jing were simply Yin, how could one speak of "storing Jing"? How could it store itself? This makes no logical sense. Strictly speaking, "Jing" actually refers to the accumulated state of Yang Qi. The accumulated state of energy is called "Jing." The greater the explosive energy of something, the better its accumulated state of Yang Qi. Of course, in *Neijing* and *Zhongji*, "Jing" has many other explanations; here I analyze it from the most fundamental principles. Jing is the aggregated state of Yang Qi, not the released state. The "storing Jing" function of Yin manifests in helping this aggregation process. Whether Yang Qi can aggregate, and whether it can transition from a released state to an accumulated state, relies on the function of Yin.
So, specifically, where is this Jing stored? *Suwen: Liu Jie Zang Xiang Lun* states: "The Kidney governs hibernation, is the root of sealing and storing, and is the abode of Jing." "Zhe" (hibernation) means hiding and lying low. The Kidney governs storage, hence it is also called the "root of sealing and storing." What does it seal and store? It seals and stores Yang Qi and Jing. This Jing, which is the aggregated state of Yang Qi, is sealed and stored in the territory of the Kidney. Hence, it is said to be the "abode of Jing." The Kidney corresponds to Winter in the annual cycle, and Winter governs storage; among the Five Zang Organs, the Kidney belongs to Yin, specifically Yin within Yin. This corresponds to the aforementioned Yin as Ti (substance) and the function of storing Jing. Therefore, the aforementioned Ti (substance), i.e., the process of nourishing Yang Qi, is largely implemented in the Kidney. Whether Jing is sealed and stored well, and whether Yang Qi receives sufficient storage and recuperation, depends on the function of the Kidney. Only when nourishment and storage are adequate can release be good, and vitality vigorous. Thus, a person's vitality is importantly determined by the Kidney.
Once the aspect of Yin speaking of Ti (substance) is clear, it becomes evident that the purpose of Ti is to assist Yong (function). In this way, people will no longer view the relationship between Yin and Yang as oppositional. One should view opposition within unity, rather than viewing opposition solely through opposition as done in the past.
The Ti-Yong relationship of Yin and Yang can also be perceived from many aspects of life. Take rest, for example. In the past, our understanding of rest might have been relatively general, assuming that sitting down was rest and sleeping was rest. Actually, upon detailed analysis, it still involves two aspects. The aforementioned general aspect is actually contained in the character "Xiu" (Rest), which refers to this process. "Xiu means resting the mind." Stopping work for a short break is called "Xiu"; stopping daily activities and going to bed to sleep is even more "Xiu." Therefore, the character "Xiu" consists of "person" and "wood," implying a person lying on a wooden bed is "Xiu." So, what is the purpose of "Xiu"? I believe everyone is clear on this. Sleeping at night is to have abundant energy the next day; the purpose of a noon nap is the same. People with a habit of noon naps, if they suddenly skip it one day, will feel drowsy and lack spirit for the entire afternoon. Therefore, the function of "Xiu" is implemented in "Xi" (Interest/Increase). What is "Xi"? Nowadays, when people deposit money in banks, why do they do it? For this "Xi." Ten years ago, when we deposited money in banks, the annual interest rate was 9% or 8%. That is, ten thousand yuan would become ten thousand nine hundred yuan after a year, increasing by exactly nine hundred yuan. Precisely for this 9% annual interest, everyone was willing to deposit money in the bank. Therefore, this "Xi" means increase. By depositing money, benefits increase, hence it is called interest. Rest? Obviously, through the process of "Xiu," the mental and physical energy consumed during work is increased, restoring a state of abundant vitality. Thus, rest also contains both Ti-Yong and Yin-Yang aspects.
Spring and Summer are Yang, Autumn and Winter are Yin; this actually means Spring and Summer are Yong (function), and Autumn and Winter are Ti (substance). How well the Yong (function) is exerted largely depends on how good the Ti (substance) is. Therefore, how the Yong (function) of Spring and Summer performs must be grounded in Autumn and Winter, especially the Ti (substance) of Winter. *Suwen: Si Qi Tiao Shen Da Lun* states: "Therefore, the sages nourish Yang in Spring and Summer, and nourish Yin in Autumn and Winter, to follow their roots." In the past, many people did not understand this "nourishing Yin and Yang." They thought that nourishing Yang in Spring and Summer would be adding fuel to the fire, and nourishing Yin in Autumn and Winter would be snowing on top of frost. *Journal of Traditional Chinese Medicine* even organized public discussions on this issue. Actually, from the perspective of Ti and Yong, what is there to doubt? Nourishing Yang in Spring and Summer is to promote the exertion of Yong (function); nourishing Yin in Autumn and Winter is to better cultivate the Ti (substance). This discusses Yin and Yang from the perspective of Ti and Yong. Readers may extend and generalize this principle.
2. General Discussion on Cold Damage Syndrome
Above, we discussed two relationships: one of dominance/guidance, and one of Ti-Yong (Substance-Function). Once these principles of Yin and Yang are clarified, the three aforementioned questions can be answered.
(1) Cold is the Qi of Winter
First, let us look at "Cold." Cold is the righteous Qi of Winter, a point already learned in *Zhongji*. Spring is warm, Summer is hot, Autumn is cool, and Winter is cold. How does "cold" arise? As mentioned earlier, the inherent nature of Yang is heat. In Spring and Summer, Yang Qi is in a released state, and heat is dispersed outward, so the weather becomes warm and hot. However, the degree of release in Spring is smaller than in Summer, so Spring temperatures are lower than Summer temperatures. When entering Autumn and Winter, Yang Qi transitions from release to storage. Heat is stored and closed off, so the weather gradually becomes cold. But in terms of degree, the storage in Autumn is not as profound as in Winter, thus Winter temperatures are colder. This is the fundamental meaning of "cold." From this meaning, we can see that "cold" actually reflects the storage state of Yang Qi; it is the external manifestation of Yang Qi being stored. Therefore, "cold" is not only the Qi of Winter, but also the Qi of "Storage."
Now, let us temporarily set aside time and look at spatial orientation. In our country, it is well known that temperatures in the Northwest are much lower than in the Southeast. Every winter, watching the weather forecast, some northern regions drop to minus ten-plus degrees Celsius, while southern regions remain above twenty degrees Celsius. This contrast is too stark. If someone from Hainan travels to the North for business, wearing a shirt before boarding the plane, they would need to wear a fur coat upon landing. Why such a huge difference? Consulting *Neijing* clarifies this. *Suwen: Yin Yang Ying Xiang Da Lun* states: "The Northwest is Yin, the Southeast is Yang." Yang is Yong (function), i.e., release; Yin is Ti (substance), i.e., storage. From the perspective of regional orientation, the entire Northwest focuses on storage, while the entire Southeast focuses on release, thus producing this disparity in temperature. This prompts a question: learning TCM requires attention not only to time but also to spatial orientation. Time and space are identical and unified in TCM; this concept must be firmly remembered. Previously, we proposed that to truly clarify Yin and Yang, one cannot merely stay at the few points in books but must have personal experience. One must cultivate the habit of thinking with Yin and Yang in all matters. For instance, we living in Nanning, although close to Spring Festival, still wear shirts. Why? If we do not think about and clarify this from the perspective of Yin and Yang, then as a student of TCM, you become numb. With such numbness, I see little possibility of mastering TCM.
(2) How to Nourish Storage