生生子曰∶夫五行者，一水、二火、三木、四金、五土，咸有所也，何以然？《素问》运气曰∶水之
为言润也（阴气濡润，任养万物也），火之为言化也（阳在上，阴在下，毁然盛而化生万物也），木之为
言触也（阳气触动，冒地而生地），金之为言禁也（阴气始，禁止万物而揪敛），土之为言吐也（含吐万物
，将生者出，将死者归，为万物家）。水生于一，《灵枢经》曰∶太一者，水之尊号。一，数之始也。天
地未分，万物未成之初，莫不先见于水，先地之母，后万物之源。以今验之，则草木子实未就，人虫胎卵
胚胎皆水也，故天一生水。一，阳数也；子，北方水之位也。子者，阳生之初，故水曰一。地二生火；二，
阴数也；午，南方火之位也。午者，阴生之初，故火曰二。天三生木；三，奇之数；木
居东，东亦阳也，故木曰三。地四生金；四，偶之数；金居西，西亦阴也，故金曰四。天五生土；五者
，奇之数，亦阳也；土应西南长夏，故土曰五。以上下左右合而观之，卒莫不有一定之理，而人身应
之。午位居上，故火旺于午，在人以心应之，故心居上。子位居下，水旺于子，在人以肾应之，故肾居
下。卯位居左，木旺于卯，在人以肝应之，故肝居左。酉位居右，金旺于酉，在人以肺应之，故肺居右
。中者，土位，土居未，在人以脾胃应之，故脾胃居中。此五行不易之定位也（观五行一定之理，则火
不在下部，尤可见矣）。
生生子说：所谓五行，即一水、二火、三木、四金、五土，它们各自都有其特定的含义和依据，这是为什么呢？《素问》的运气学说指出：水的“水”字，意思是润（阴气濡润，滋养万物），火的“火”字，意思是化（阳气在上，阴气在下，炽盛而化生万物），木的“木”字，意思是触（阳气触动，冲破地面而生出），金的“金”字，意思是禁（阴气起始，禁止万物生长并收敛），土的“土”字，意思是吐（包容吐出万物，将生的排出，将死的回归，是万物的家园）。水生于“一”，《灵枢经》说：太一是水的尊号。“一”，是数的开始。天地尚未分开，万物尚未形成之初，无不先见于水，它是地的母亲，万物的源头。用现在的事物来验证，草木的种子果实尚未成熟时，人虫的胎卵胚胎都是水，所以天一生水。“一”是阳数；“子”，是北方水的方位。“子”，是阳气初生之时，所以水称为一。地二生火；“二”，是阴数；“午”，是南方火的方位。“午”，是阴气初生之时，所以火称为二。天三生木；“三”，是奇数；木居于东方，东方也是阳位，所以木称为三。地四生金；“四”，是偶数；金居于西方，西方也是阴位，所以金称为四。天五生土；“五”是奇数，也属阳；土对应西南方的长夏季节，所以土称为五。以上下左右综合来看，最终无不有一定的道理，人体也与之相应。午位居上，所以火旺于午时，在人体以心与之相应，所以心居上部。子位居下，水旺于子时，在人体以肾与之相应，所以肾居下部。卯位居左，木旺于卯时，在人体以肝与之相应，所以肝居左侧。酉位居右，金旺于酉时，在人体以肺与之相应，所以肺居右侧。中者，是土的位置，土居于未方，在人体以脾胃与之相应，所以脾胃居中。这就是五行不可改变的固定位置（观察五行一定的道理，就可以看出火不在下部了）。
Shengshengzi said: The so-called Five Elements are Water, Fire, Wood, Metal, and Earth, corresponding to the numbers One, Two, Three, Four, and Five respectively. Each has its specific meaning and rationale. Why is this? The *Suwen* (Basic Questions) on Yungqi (Movement of Qi) states: The term "Water" implies moistening (Yin Qi moistens and nourishes all things); the term "Fire" implies transformation (Yang Qi is above, Yin Qi is below, blazing hot and transforming into all things); the term "Wood" implies touching or penetrating (Yang Qi stirs and breaks through the earth to grow); the term "Metal" implies restriction or prohibition (Yin Qi begins, restricting all things and gathering them); the term "Earth" implies spitting out or containing (containing and releasing all things, expelling those about to be born, returning those about to die, serving as the home for all things). Water originates from One. The *Ling Shu Jing* (Spiritual Pivot) says: Taiyi is the honorific title of Water. "One" is the beginning of numbers. Before Heaven and Earth were separated and before all things were formed, nothing was not first seen in Water; it is the mother of Earth and the source of all things. Verifying with current observations, when plant seeds and fruits are not yet mature, and human or insect embryos within eggs or wombs are forming, they are essentially Water. Thus, Heaven generates Water with One. "One" is a Yang number; "Zi" (Rat) is the position of Water in the North. "Zi" represents the initial birth of Yang, hence Water is called One. Earth generates Fire with Two. "Two" is a Yin number; "Wu" (Horse) is the position of Fire in the South. "Wu" represents the initial birth of Yin, hence Fire is called Two. Heaven generates Wood with Three. "Three" is an odd number; Wood resides in the East, and the East is also a Yang position, hence Wood is called Three. Earth generates Metal with Four. "Four" is an even number; Metal resides in the West, and the West is also a Yin position, hence Metal is called Four. Heaven generates Earth with Five. "Five" is an odd number and also belongs to Yang; Earth corresponds to the late summer season in the Southwest, hence Earth is called Five. Viewing these together with up, down, left, and right, there is ultimately no principle that is not fixed, and the human body corresponds to them. Wu is positioned at the top, so Fire is prosperous at Wu; in the human body, the Heart corresponds to it, so the Heart is located superiorly. Zi is positioned at the bottom, so Water is prosperous at Zi; in the human body, the Kidney corresponds to it, so the Kidney is located inferiorly. Mao is positioned on the left, so Wood is prosperous at Mao; in the human body, the Liver corresponds to it, so the Liver is located on the left. You is positioned on the right, so Metal is prosperous at You; in the human body, the Lung corresponds to it, so the Lung is located on the right. The Center is the position of Earth; Earth resides in the Wei direction; in the human body, the Spleen and Stomach correspond to it, so the Spleen and Stomach are located centrally. These are the unchangeable fixed positions of the Five Elements (Observing the fixed principles of the Five Elements, it becomes evident that Fire is not located in the lower part).