异法者，一病而治各不同，有砭石毒药灸 微针导引诸法也。方宜者，东方砭石，西方毒药，
北方灸 ，南方微针，中央导引
也。圣人杂合以治，用各不同，五方之病，皆得其宜，故曰异法方宜。
黄帝问曰∶医之治病也，一病而治各不同，皆愈何也？
即异法方宜之义。
岐伯对曰∶地势使然也，故东方之域，天地之所始生也。鱼盐之地，海滨傍水，其民食鱼而嗜咸，
皆安其处，美其食。鱼者，使人热中，盐者，胜血，故其民皆黑色疏理，其病皆为痈疡。其治宜
砭石，故砭石者，亦从东方来。
砭，音边，余篇同。五方地势不同，致使为病各异，故东方之域，天地之所始生也。东方有鱼盐之利，
故曰鱼盐之地。盐出海滨，鱼生水中，故曰海滨傍水。鱼盐之地，故其民食鱼而嗜咸。地虽傍水，而皆安其
处，食鱼嗜咸，而皆美其食。鱼性善动，不为水寒，故多食鱼者，使人热中，盐性味咸，物着坚凝，故多
食盐者，咸味胜血。傍水嗜咸，故其民皆黑色。热中胜血，故其民皆疏理。疏理，血弱而腠理空疏也，其
病皆为痈疡。疏理之所致也，其治宜砭石，以石为针，所以治痈疡也。夫用砭石之治，是从东方而遍及
于宇内，故砭石者，亦从东方来。
西方者，金玉之域，沙石之处，天地之所收引也。其民陵居而多风，水土刚强，其民不衣而祸
荐，其民华实而脂肥，故邪不能伤其形体。其病生于内，其治宜毒药，故毒药者，亦从西方来。
处，去声。下南方，盛处同。西方金体坚劲，故西方者金玉之域。沙藏金，石藏玉，故为沙石之处。西
方主秋，乃天地之所收引也。地势高，故其民陵居。陵，高阜之岗陵也。陵居地高，故多风。西方金也，
故水土刚强，刚强于外，其民不衣而褐荐。刚强于内，其民华实而脂肥。内外刚强，故邪不能伤其形体，
其病皆生于内七情。水土刚强，借毒药以宣通，故其治宜毒药。毒药者，中品下品，有毒之药也。是
毒药之治，始于西方，故毒药者，亦从西方来。
北方者，天地所闭藏之域也，其地高，陵居，风寒冰冽，其
民乐野处而乳食。藏寒生满病，其治宜灸 。故灸 者，亦从北方来。
闭藏之藏，如字， ，音热，余篇同。北方冬令阴寒，故天地所闭藏之域也。地余西北，故其地高，
亦如西方之陵居也。风寒冰冽者，其地多风而寒，如冰之凛冽也。居，常居也；处，暂处也。其
民乐野处，有时不欲居高也。旷野兽多，故乐野处而乳食。北方寒水气胜，内藏阴寒，多生胀满之病，
其治宜艾火灸 ，以温藏寒，是灸 之治，始于北方，故灸 者，亦从北方来。
南方者，天地所长养，阳之所盛处也。其地下，水土弱，雾露之所聚也。其民嗜酸而食 ，
故其民皆致理而赤色，其病挛痹，其治宜微针，故九针者，亦从南方来。
长，上声， 作腐。南方，火也，故为天地之所长养，阳气所盛之处也，地陷东南，故其地下。地高
则刚，地下则柔，故水土弱，地土卑下，水湿从之，故雾露之所聚也。雾露所聚，其民故嗜酸而食腐。东
南地弱，则嗜生我之味。其民嗜酸，木生火也。上文东方嗜咸，水生木也。西北地上有余，则不言所嗜矣。
酸味收敛，故其民皆致理，致理腠理致密也。嗜酸则木生火，故致理而赤色。水土弱，雾露聚，故其病挛
痹。拘挛，痿痹也。其治宜微针。按《灵枢·九针论》，黄帝欲以微针通其经脉，微针，小针也。岐伯论
小针而及于九针，故曰九针者，亦从南方来。
中央者，其地平以湿，天地所以生万物也众。其民食杂而不劳，故其病多痿厥寒热，其
治宜导引按跷，故导引按跷者，亦从中央出也。
中央，土之正位也，故其地平以湿。平者，不高不陷，湿者，滋润也。平正滋润，万物乃生，故天
地所以生万物也众。万物会聚，故其民食杂。四方来归，故其民不劳。不劳则四肢不强，故其病多
痿厥。痿厥，痿痹厥逆也。食杂，则阴阳乖错，故其病多寒热。寒热阴阳偏胜也。其治宜导引，以和阳阴。
按跷，以和四肢，是导引按跷之治，始于中央，故导引按跷者，亦从中央出也。四方会聚，
故曰来，中央四布，故曰出。
故圣人杂合以治，各得其所宜。故治所以异，而病皆愈者，得病之情，知治大体也。
圣人不拘五方之病，不泥五方之宜。如东方砭石，而西北南中皆用之。西方毒药，而东北南中皆
用之。北方灸 ，南方微针，中央导引按跷，而诸方皆用之。故杂合以治，各得其宜。治各不同，
故治所以异，而病皆愈者，得病之情，知治之大体也。异法方宜，此之谓也。
The term "Yi Fa" (Different Methods) refers to the fact that while treating the same disease, the therapeutic methods may vary, including techniques such as Bian Shi (Stone Lancets), Yao Du (Medicinal Drugs), Jiu Ai (Moxibustion), Wei Zhen (Fine Needles), and Dao Yin An Qiao (Guiding and Leading Exercises). The term "Fang Yi" (Regional Suitability) indicates that the East is suitable for Bian Shi, the West for Yao Du, the North for Jiu Ai, the South for Wei Zhen, and the Central region for Dao Yin. The Sages combined these various methods for treatment, applying them flexibly according to specific circumstances, ensuring that diseases in all five regions received appropriate care; hence it is called "Yi Fa Fang Yi" (Different Methods and Regional Suitability).
Yellow Emperor asked: When physicians treat diseases, why do different methods applied to the same disease all result in recovery?
(This sentence elucidates the meaning of "Yi Fa Fang Yi".)
Qi Bo replied: This is caused by geographical terrain and environment. Therefore, the Eastern region is where the Qi of Heaven and Earth begins to generate. It is a land of fish and salt, located near the seashore and waters. Its people eat fish and have a preference for salty food, are content with their living conditions, and find their food delicious. Eating fish tends to cause internal heat, while excessive salt consumption can deplete blood (Sheng Xue). Consequently, the people there often have dark skin and loose interstitial spaces (Cou Li - pores and tissue spaces), and their diseases are mostly abscesses and ulcers (Yong Yang). For such conditions, Bian Shi (Stone Lancets) is suitable; thus, the use of Bian Shi originated from the East.
Bian is pronounced "bian". The five regions have different terrains, leading to different diseases. Thus, the East is where Heaven and Earth's Qi begins to generate. The East has the benefits of fish and salt, hence called the "Land of Fish and Salt." Salt comes from the seaside, and fish live in water, hence "near the seashore and waters." Being a land of fish and salt, the people eat fish and prefer salty flavors. Although near water, they are content with their dwellings and find their diet delightful. Fish are active and not hindered by cold water, so consuming much fish causes internal heat. Salt is salty and causes substances to solidify; thus, consuming much salt leads to salty flavors overpowering the blood. Living near water and preferring salt results in dark skin. Internal heat and depleted blood lead to loose Cou Li. Due to loose Cou Li, their diseases are mostly Yong Yang. Such conditions are treated with Bian Shi, which are stone needles used to treat abscesses. The therapy using Bian Shi spread from the East to the whole country, so Bian Shi therapy also came from the East.
The Western region is an area of gold and jade, full of sand and stones, where the Qi of Heaven and Earth gathers and contracts. Its people live on hills, experience much wind, and inhabit an area with tough soil and water. They wear coarse clothes and sleep on straw mats, are robust and fatty, so external pathogens cannot harm their bodies. Their diseases arise internally (from emotions), and the treatment is suitable for Yao Du (Medicinal Drugs); thus, Yao Du therapy also originated from the West.
Chu is pronounced "chu". The West belongs to Metal, with a tough constitution, hence it is the land of gold and jade. Sand hides gold, and stones hide jade, hence it is a place of sand and stones. The West governs Autumn, the time when Heaven and Earth's Qi gathers and contracts. The terrain is high, so people live on hills. Ling refers to high mounds. Living on high ground means more wind. The West belongs to Metal, so the soil and water are tough. Outwardly tough, people wear brown coarse cloth and sleep on straw reeds. Inwardly tough, people are robust and fatty. Being tough inside and out, external pathogens cannot harm the body, and diseases arise from internal Seven Emotions. Tough soil and water require medicinal drugs to promote circulation, so treatment suits Yao Du. Yao Du refers to toxic medicines of middle and lower grades. This therapy began in the West, so Yao Du therapy also came from the West.
The Northern region is where Heaven and Earth's Qi is stored and hidden. The terrain is high, people live on hills, the wind and cold are biting like ice, and the people enjoy living in the wild and eating dairy. Coldness in the viscera causes distension and fullness diseases, and the treatment is suitable for Jiu Ai (Moxibustion); thus, Jiu Ai therapy also originated from the North.
Cang is read as original. Jiu is pronounced "re". Winter in the North is yin and cold, hence it is the region of storage. Located in the northwest, the terrain is high, similar to the hills in the West. Wind and cold are biting due to frequent wind and cold weather resembling ice. Ju means permanent residence; Chu means temporary stay. People enjoy temporary stays in the wild because wild beasts are abundant. The North has strong Water Qi, causing internal yin cold and many distension diseases. Treatment suits Moxibustion with moxa fire to warm the cold viscera. Thus, Moxibustion therapy began in the North, so Jiu Ai therapy also came from the North.
The Southern region is where Heaven and Earth grow and nourish, and where Yang Qi is abundant. The terrain is low, the soil and water are weak, and it is a gathering place for fog and dew. The people prefer sour flavors and eat fermented foods. Consequently, their skin texture is dense, their complexion is red, and their diseases are mainly spasms and bi-syndrome (painful obstruction). The treatment is suitable for Wei Zhen (Fine Needles); thus, the Nine Needles therapy also originated from the South.
Zhang is pronounced "zhang". Fu refers to fermentation/putrefaction. The South belongs to Fire, hence it is where Heaven and Earth grow and nourish, and where Yang Qi is abundant. The land sinks in the southeast, hence the low terrain. High terrain is tough; low terrain is soft, hence weak soil and water. Low land attracts dampness, gathering fog and dew. Gathering fog and dew leads people to prefer sour flavors and eat fermented foods. The weak southeast favors flavors that generate it (Wood generates Fire; Sour belongs to Wood). As mentioned earlier, the East prefers salty (Water generates Wood). The northwest has surplus height, so no specific flavor preference is mentioned. Sour flavor has a consolidating effect, leading to dense Cou Li. Preferring sour leads to Wood generating Fire, resulting in dense Cou Li and red complexion. Weak soil and water, gathering fog and dew, cause spasms and bi-syndrome. Spasms refer to flaccidity and bi-syndrome. Treatment suits Wei Zhen. According to *Ling Shu: Jiu Zhen Lun*, Yellow Emperor wanted to use fine needles to unblock meridians; Wei Zhen means small needles. Qi Bo discussed small needles in relation to the Nine Needles, hence saying Nine Needles therapy also came from the South.
The Central region has flat and humid terrain, producing abundant things under Heaven and Earth. The people eat a mixed diet and do not labor hard, so their diseases are mostly atrophy, reversal cold/hot, and alternating chills and fever. The treatment is suitable for Dao Yin An Qiao (Guiding and Leading Exercises and Manipulation); thus, this therapy also emerged from the Central region.
The Center is the proper position of Earth, hence flat and moist. Flat means neither high nor sunken; moist means nourishing. Flat, upright, and nourishing allows things to grow, hence abundant production. Things gather, so people eat a mixed diet. People from four directions return, so people do not labor. Lack of labor leads to weak limbs, causing atrophy and reversal. Atrophy and reversal refer to flaccidity and reversal cold/heat. Mixed diet leads to yin-yang imbalance, causing chills and fever. Chills and fever indicate yin-yang excess. Treatment suits Dao Yin to harmonize yin and yang. An Qiao harmonizes the four limbs. Thus, Dao Yin An Qiao therapy began in the Center, emerging from the Central region. Four directions converge, hence "come"; Center radiates outward, hence "out".
Therefore, the Sages combine various therapies for treatment, each obtaining its suitability. Although treatments differ, diseases recover because one understands the nature of the disease and the general principles of treatment.
Sages do not rigidly adhere to diseases of the five regions or stick to single regional suitability. For example, Bian Shi from the East is used in the Northwest, South, and Center. Yao Du from the West is used in the Northeast, South, and Center. Jiu Ai from the North, Wei Zhen from the South, and Dao Yin An Qiao from the Center are all used universally. Thus, combining therapies ensures each gets its suitability. Treatments differ, yet diseases recover because one grasps the disease's reality and knows the general treatment principles. This is what is meant by "Yi Fa Fang Yi".