帝曰∶四时之气，至有早晏高下左右，其候何如？岐伯曰∶行有逆顺，至有迟速，故太过者化先天，不及
者化后天。帝曰∶愿闻其行何谓也？岐伯曰∶春气西行，夏气北行，秋气东行，冬气南行，故春气始于
下，秋气始于上，夏气始于中，冬气始于标。春气始于左，秋气始于右，冬气始于后，夏气始于前，此四时正化之常。
故至高之地，冬气常在，至下之地，春气常在。（六元正纪大论）
黄帝问曰∶六化之正，六变之纪何如？岐伯对曰∶夫六气正纪，有化有变，有胜有复，有用有病。不同其
候。夫气之所至也，厥阴所至为和平，少阴所至为暄，太阴所至为埃溽，少阳所至为炎暑，阳明所至为清劲，
太阳所至为寒 ，时化之常也。厥阴所至为风府、为璺启，少阴所至为火府、为舒荣，太阴所至为雨府、为圆
盈，少阳所至为热府、为行出，阳明所至为司杀府、为庚苍，太阳所至为寒府、为归藏，司化之常也。厥阴所
至为生、为风摇，少阴所至为荣、为形见，太阴所至为化、为云雨，少阳所至为长、为蕃鲜，阳明所至为收、
为雾露，太阳所至为藏、为周密，气化之常也。厥阴所至为风生，终为肃；少阴所至为热生，中为寒；太阴所
至为湿生，终为注雨；少阳所至为火生，终为蒸溽；阳明所至为燥生，终为凉；太阳所至为寒生，中为温，德
化之常也。厥阴所至为毛化，少阴所至为羽化，太阴所至为裸化，少阳所至为羽化，阳明所至为介化，太阳所
至为鳞化，德化之常也。厥阴所至为生化，少阴所至为荣化，太阴所至为濡化，少阳所至为茂化，阳明所至为
坚化，太阳所至为藏化，布政之常也。厥阴所至为飘怒大凉，少阴所至为大暄寒，太阴所至为雷霆骤注烈风，
少阳所至为飘风燔燎霜凝，阳明所至为散落温，太阳所至为寒雪冰雹白埃，气变之常也。厥阴所至为挠动、为
迎随，少阴所至为高明焰、为曛，太阴所至为沉阴、为白埃、为晦暝，少阳所至为光显、为彤云、为曛，阳明
所至为烟埃、为霜、为劲切、为凄鸣，太阳所至为刚固、为坚芒、为立令，行之常也。凡此十二变者，报德以
德，报化以化，报政以政，报令以令，气高则高，气下则下，气后则后，气前则前，气中则中，气外则外，位
之常也。（六元正纪大论）
Yellow Emperor asked, "The Qi of the four seasons arrives with variations in early and late timing, high and low position, and left and right direction. What are these indications?" Qibo replied, "The movement of Qi has its favorable (Shun) and unfavorable (Ni) directions, and its arrival has speed differences. Therefore, when Qi is excessive (Tai Guo), it transforms before the season; when Qi is deficient (Bu Ji), it transforms after the season."
The Yellow Emperor said, "I wish to hear what is meant by 'movement' (Xing)." Qibo replied, "Spring Qi moves westward, Summer Qi moves northward, Autumn Qi moves eastward, and Winter Qi moves southward. Thus, Spring Qi begins from below, Autumn Qi begins from above, Summer Qi begins from the center, and Winter Qi begins from the periphery/biao. Spring Qi begins on the left, Autumn Qi begins on the right, Winter Qi begins at the back, and Summer Qi begins at the front. These are the normal patterns of the four seasons' transformation. Therefore, in places of extreme height, Winter Qi often prevails; in places of extreme depth/lowness, Spring Qi often prevails." (From *Su Wen: Da Yuan Zheng Ji Da Lun*)
The Yellow Emperor asked, "What are the norms of the six transformations (Liu Hua) and the records of the six variations (Liu Bian)?" Qibo answered, "In the normal records of the Six Qi (Liu Qi), there are normal transformations, variations, excesses (Sheng), reversals (Fu), functional manifestations, and pathological conditions. Their signs differ. Wherever Qi arrives: Jueyin (Liver/Gallbladder) manifests as peace; Shaoyin (Heart/Pericardium) manifests as warmth; Taiyin (Spleen/Stomach) manifests as dusty humidity; Shaoyang (Sanjiao/Gallbladder) manifests as heat and summer heat; Yangming (Large Intestine/Lung) manifests as coolness and crispness; Taiyang (Bladder/Kidney) manifests as cold. This is the normal seasonal transformation.
Where Jueyin arrives, it is the residence of Wind, causing cracks to open; where Shaoyin arrives, it is the residence of Fire, causing expansion and flourishing; where Taiyin arrives, it is the residence of Rain, causing fullness and盈 (completeness); where Shaoyang arrives, it is the residence of Heat, causing emergence and growth; where Yangming arrives, it is the residence of Killing, causing a green/cyan appearance; where Taiyang arrives, it is the residence of Cold, causing storage and hiding. This is the normal function of transformation.
Where Jueyin arrives, there is generation and wind shaking; where Shaoyin arrives, there is prosperity and visible forms; where Taiyin arrives, there is transformation and cloud/rain; where Shaoyang arrives, there is growth and lush freshness; where Yangming arrives, there is gathering/restriction and fog/dew; where Taiyang arrives, there is storage and tightness/secrecy. This is the normal process of Qi transformation.
Where Jueyin arrives, Wind generates, ultimately leading to肃 (solemnity/cold); where Shaoyin arrives, Heat generates, midway leading to Cold; where Taiyin arrives, Dampness generates, ultimately leading to pouring rain; where Shaoyang arrives, Fire generates, ultimately leading to steaming humidity; where Yangming arrives, Dryness generates, ultimately leading to Coolness; where Taiyang arrives, Cold generates, midway leading to Warmth. This is the normal virtue of transformation.
Where Jueyin arrives, hair-covered creatures transform; where Shaoyin arrives, feathered creatures transform; where Taiyin arrives, naked humans transform; where Shaoyang arrives, feathered creatures transform; where Yangming arrives, shelled creatures transform; where Taiyang arrives, scaled creatures transform. This is the normal virtue of transformation.
Where Jueyin arrives, there is generative transformation; where Shaoyin arrives, there is flourishing transformation; where Taiyin arrives, there is moistening transformation; where Shaoyang arrives, there is luxuriant transformation; where Yangming arrives, there is hardening transformation; where Taiyang arrives, there is storing transformation. This is the normal administration of governance.
Where Jueyin arrives, there are raging winds and great coolness; where Shaoyin arrives, there is great heat followed by sudden cold; where Taiyin arrives, there are thunderstorms, sudden heavy rain, and fierce winds; where Shaoyang arrives, there are whirlwinds, burning fires, and frost condensation; where Yangming arrives, there is scattering and warmth; where Taiyang arrives, there is cold snow, hail, and white dust. This is the normal variation of Qi.
Where Jueyin arrives, there is trembling and following along; where Shaoyin arrives, there is bright flame and dusk darkness; where Taiyin arrives, there is deep yin, white dust, and gloomy darkness; where Shaoyang arrives, there is brightness, red clouds, and dusk darkness; where Yangming arrives, there is smoke and dust, frost, cutting crispness, and desolate sounds; where Taiyang arrives, there is rigidity and solidity, sharp points, and established commands. This is the normal operation of Qi.
These twelve variations respond to virtue with virtue, to transformation with transformation, to governance with governance, and to command with command. High Qi responds to high positions, low Qi to low positions, rear Qi to the rear, front Qi to the front, central Qi to the center, and external Qi to the exterior. This is the normal correspondence of positions." (From *Su Wen: Da Yuan Zheng Ji Da Lun*)