1001.42 meters! Why is the world's first well over a thousand meters deep called the "Great Well"?

About 200 million years ago, Zigong was in a critical period of land-sea transition, with large amounts of brine, rock salt and natural gas buried here. 2,000 years ago, the ancestors living here accidentally discovered the brine "buried" here 200 million years ago, and then began their tireless pursuit of this scarce substance.

They dug wells to extract brine, from large-diameter salt wells to long-tube wells, and eventually crossed thousands of meters of rock strata, creating the world's highest drilling achievement.

Not only that, the development and prosperity of the salt mining industry also promoted the formation of cities, gave birth to China's capitalism, and ultimately gave birth to the city of Zigong and its unique culture rooted in brine.

▲Shenhai Well. Photo by Li Zhongdong The Great Wall of China is called the "Great Wall" by foreign humanists, and the numerous salt wells in Zigong are called the "Great Wells" by foreign scholars.

Professor Wojciech, a famous contemporary German scholar, once wrote an article about Zigong Salt Wells for the famous American scientific magazine "Science and Americans" under the title "China's Great Well".

In this article he wrote:

One hundred and fifty years ago, a well as deep as one thousand meters was dug in China to extract brine for making salt... This well was the pinnacle of eight hundred years of well-drilling technology - the 'impact drilling method'. Its achievement was the best in the world at that time, and was four hundred years ahead of European technology. This well-drilling technology has become another great invention that the Chinese are proud of, following the four great inventions of papermaking, printing, gunpowder and the compass.

▲Zigong Salt Field. Photo by Sun Mingjing

01 Fushijing: the earliest salt well in Zigong

Fushi Well, located in Fushun County, Zigong City, is considered the first salt well in Zigong's history, marking the beginning of Zigong's salt industry. The discoverer of this well was a Liao tribe member named Mei Ze. According to Wang Xiangzhi's "Geographical Records" in the Song Dynasty, Mei Ze "was hunting and saw a spring on a rock. He drank the salty water, so he chiseled the rock 300 feet deep, and a salt spring gushed out, which he boiled to make salt."

During the reign of Emperor Zhang of the Eastern Han Dynasty (76-88 AD), people dug a salt well in the Mei Ze salt spring area, which is today Chengguan Town, Fushun County.

▲Han brick salt mining diagram.

During the Northern and Southern Dynasties, Fushi Well was well-known in Sichuan, and the "Fushi County" was established because of it. During the Sui and Tang Dynasties, the "Fushi Salt Well" had set a record of producing more than 6,100 kilograms of salt per day, and the tax from the well accounted for more than 20% of the total annual tax of salt wells in Sichuan.

In the Tang Dynasty, in order to avoid the taboo of "Shi" in Li Shimin's name, "Fushi County" was changed to "Fuyi County", and "Fushi Salt Well" was renamed "Fuyi Salt Well". In the Song Dynasty, it was changed to "Fushun County". In the middle of the Ming Dynasty, with the depletion of brine resources, this ancient salt well that had been in continuous production for more than a thousand years was finally abandoned. However, "Fushun County (Fushi County)" originated from "Fushi Salt Well" has remained unchanged for 1446 years, becoming a legend in the history of Zigong's salt industry and the history of Zigong's establishment as a city.

▲Picture of digging a well.

02 Zhuotong Well: A Revolution in Well Salt Mining

By the Song Dynasty, even experienced salt workers encountered troubles.

When the shallow brine gradually dried up, the Triassic brine buried deeper in the sea was no longer accessible to the large-diameter shallow wells that were widely used at the time. But soon, the salt workers found a new way to mine the brine, which was the Zhuotong Well.

"Dig the ground and plant bamboo to make a Zhuotong well." This is a salt well that uses the local unique nanmu bamboo to absorb brine.

Its principle seems very simple today, that is, using the lever principle of the ancients pounding rice, a drill is driven up and down by pedaling, so as to achieve the purpose of digging a well. Although the principle is simple, it was a revolutionary innovation at the time and a very advanced way of digging a well.

▲Zhuotong Well was dug using the lever principle of pounding rice.

Su Shi, a contemporary of Su Shi, once gave a wonderful description of this new brine mining technology. In his "On Shu Salt", he wrote, "Since the reign of Emperor Qingli and Emperor Huangyou, Shu first created the 'Zhuotong'. It uses a round-bladed chisel as big as a bowl, some of which are several dozen feet deep. It uses giant bamboos without joints, with male and female bamboos connected to form a well, and uses a partition to put fresh water in horizontally, so that the salty spring will flow up. It also uses a smaller bamboo to make a bucket for entering and exiting the well. It has no bottom and a hole on the top, and a few inches of cooked leather is hung on it. It goes in and out of the water, and the air opens and closes it by breathing. One tube can hold several buckets of water. All tube wells use machinery, and everyone knows the benefits."

Su Dongpo, who is good at writing, uses the method of plain drawing to convey a lot of information about Zhuotong Well to us. First, he affirmed the Sichuan patent right of "creating it in Shu", and then explained the key technical points of Zhuotong Well: circular blade drilling, large bamboo tube "casing protection", small bamboo tube "one-way valve lifting method"; finally, he also investigated the practical effect of this "patent" and said "everyone knows where the benefits are".

This is probably the earliest "patent certificate" in our country.

▲In the Ming Dynasty, brine was transported by ox carts.

The emergence of the Zhutong Well overcame the limitations of traditional large-diameter shallow wells, and for the first time, mankind extended its tentacles to unprecedented depths of the earth.

This well-drilling process, which was later called "impact drilling" by scholars, became a pioneer in the world's drilling technology. It is considered to be the fifth greatest invention of ancient my country after papermaking, compass, movable type printing and gunpowder, and is another major contribution to world civilization.

▲Ancient small-diameter drill bit.

03 Shenhai Well: The Great Well

In the limestone of the Triassic Leikoupo Formation and Jialingjiang Formation in the Sichuan Basin, which dates back about 200 million years, there is a kind of black brine buried, which is called black brine by local people. Compared with the yellow brine with less salt content, the salt content of black brine is more coveted by salt merchants. However, this black brine is buried in deeper strata than yellow brine and is difficult to obtain.

During the reigns of Emperor Qianlong and Emperor Jiaqing of the Qing Dynasty, the depth of the salt wells at the Zigong Salt Field had reached 500-800 meters. The continuous outflow of black brine further stimulated other salt merchants at the Zigong Salt Field to drill deeper.

Finally, in the 15th year of Daoguang (1835), the Shenhai Well located in Da'anzhai, Zigong, finally broke through the numerous rock strata. Extremely salty black brine gushed out from the wellhead, exciting everyone present.

However, no one knew that the well was already 1001.42 meters deep. 178 years ago, the Zigong people, with their "unfathomable ingenuity and ingenuity", inadvertently dug the first 1,000-meter-deep well in human history.

Ten years later, in 1845, Americans also set the highest drilling record in the United States in the Kano area, but the well depth was only 518 meters.

▲Shenhai Well. Photo by Li Zhongdong

The excavation of Shenhai Well not only revealed the secrets of the Triassic Jialingjiang limestone strata, but also promoted the rapid development of the regional economy. Salt gentry and merchants from all over the country came in droves, dug wells and set up stoves around it, and 198 wells were drilled in the area of ​​1.2 square kilometers. For a time, there was a prosperous scene with "overhead cranes" everywhere, cooking stoves everywhere, pipes everywhere, and clouds and mists everywhere.

As early as 1980, UNESCO's Museum magazine made a special report on the Shenhai Well, and believed that China's drilling technology in the early 19th century was far ahead of that of Western countries.

Today, this ancient salt-making workshop, which has been preserved for a century, still follows the ancient process to extract brine from thousands of meters below, and then uses a low-pressure spark round pot to make table salt, which is then distributed to thousands of households.

This place has become Zigong's most authentic well salt production site and living fossil of the salt industry, completely reproducing the production scenes of drilling, gas extraction and salt making in the late Qing Dynasty.

▲Zigong Salt Field in the 1930s. Photo by Sun Mingjing

04 A model for comprehensive utilization of brine and natural gas

In the Sichuan Basin, natural gas is often associated with brine. The early discovery and use of natural gas all originated from salt wells, and was used to boil salt. Sichuan is the earliest region in the world to use natural gas to boil salt. With the continuous improvement of salt well drilling technology, natural gas extraction technology has also been continuously improved.

In the middle of the Ming Dynasty, natural gas was no longer just a by-product of salt well development. Independent wells for the purpose of extracting natural gas began to appear, and the salt and gas were extracted separately. The system of moving salt and frying, or moving gas and frying gradually took shape.

During this period, the first industrially exploited gas field in human history, the Ziliujing gas field, was discovered and exploited, which greatly promoted the development of Zigong's salt industry. At the same time, the technical level of natural gas extraction was greatly improved, making it a leader in natural gas extraction in my country.

In the middle of the 19th century (around 1835), the artesian well invented the Kangpan gas extraction, which realized the process of open hole completion, unobstructed extraction, gas extraction while drilling, brine extraction while drilling, and gas extraction while brine extraction, which wrote a magical and glorious page in the history of natural gas development.

▲Picture of boiling salt with well fire.

05 The last 18-seat Skytrain

The widespread use of Zhuotong Wells has brought two major changes to Zigong. Going down, we passed through the Cretaceous and Jurassic rock formations and extended the salt wells to the Triassic Leikoupo Formation and Jialingjiang Formation formations dating back more than 200 million years. The high-quality black brine buried there has made Zigong a thousand-year-old salt capital.

At the same time, the supports used for extracting brine, scouring wells and washing wells on the ground have been erected higher and higher as the mining depth has deepened. This kind of building, which is made of hundreds of light and corrosion-resistant fir trees, has a nice name - overhead crane. This special building once stood like a dense forest in the major salt wells of Zigong, which was spectacular and became the symbol and landmark of Zigong.

▲Dafenbao Skytrain Group. Photo by Sun Mingjing

According to historical records, Zigong has a large number of ancient wells and overhead cranes in the nearly 2,000 years of salt production. In 1914, there were "960 water and fire wells" in Ziliujing alone, and more than 11,800 abandoned wells, so there is a saying that "there are as many salt wells (overhead cranes) in Ziliujing as hemp sieves."

In 1938, when the War of Resistance Against Japanese Aggression was in full swing, photographer Sun Mingjing, then a professor at Jinling University and later a teacher of Zhang Yimou and others, once brought a 16mm special Kodak camera and a 120-type Zeiss Ikon camera to record the magnificent scene of Zigong with its numerous overhead cranes, dense salt wells, winding pipes and steam rising from the kitchens.

Even Mr. Sun, who was used to seeing the bustling skyscrapers in Shanghai, was surprised at the height of the Zigong overhead crane. Some of these derrick cranes, which were made only of thin fir wood, bamboo strips and hemp ropes, were even taller than the tallest International Hotel in Shanghai at that time.

Salt wells and overhead cranes, one underground and one above ground, Zigong has repeatedly broken the record for the deepest well digging. However, over the years, tens of thousands of overhead cranes have mostly collapsed, burned, or been demolished.

On May 20, 2009, a sudden fire destroyed the Yuantongjing Overpass, known as Zigong's "Greeting Pine", located next to the Neiyi Expressway.

Of the 19 remaining overhead cranes in Zigong City, only 18 are still standing stubbornly between heaven and earth, looking extremely lonely and desolate. They have repeatedly broken the highest record of wooden structures in my country.

▲Golden Flow Well. Photo by Miao Ziping

06 Richest in Sichuan, Salt Provides Benefit to the World

The production of salt by digging wells in Zigong began in the reign of Emperor Zhang of the Eastern Han Dynasty. It gradually took shape during the Wei, Jin, Southern and Northern Dynasties and became world-famous during the Tang and Song Dynasties. It further developed during the Ming and Qing Dynasties and reached its peak during the reign of Emperor Xianfeng and Emperor Tongzhi of the Qing Dynasty (1851-1874), becoming the national center of well salt and becoming the richest in Sichuan.

Salt gave birth to Zigong. The two times of "Sichuan Salt to Chu" in history brought golden opportunities for building the glory of the Salt Capital.

In the third year of Emperor Xianfeng's reign (1853), the Taiping Army established its capital in Nanjing, and the transportation route of Huai salt to Hubei was blocked. The Qing court ordered Sichuan salt to be transported to Hubei. Previously, Zigong, which had few wells, opened new wells with its superb drilling technology and abundant brine and natural gas. In more than ten years, more than a hundred wells were dug, and wells with a depth of more than a kilometer were common.

By the 1870s, Zigong had 707 wells, 5,590 salt pots, and an annual salt output of nearly 200,000 tons, which brought Zigong's well salt industry into its heyday. It was the leader of Sichuan's well salt industry and was known as the "Salt Capital" and praised as "the most prosperous place in Sichuan" and "the core of Sichuan Province."

▲The historical contribution of Zigong Salt Field.

In July 1937, the Anti-Japanese War broke out, and the coastal areas fell one after another, and the sea salt was blocked. Hunan, Hubei and other provinces urgently needed Sichuan salt to help them sell. In the spring of 1939, the National Government ordered Sichuan salt to increase production and transportation, forming the second Sichuan salt to help Chu in history.

Starting from 1938, the entire salt field began to restore brine wells in large numbers, increase salt stoves, improve production, and transport more salt. During the eight years of the War of Resistance Against Japan, Zigong's annual salt production averaged 244,500 tons.

Before the war, the proportion of Zigong salt production in the total salt production in Sichuan had dropped to 45%. By 1939, it had risen to 54%, and in 1945 it accounted for 60% of the total salt production in Sichuan.

During the Anti-Japanese War, Furong East and West Salt Mine was responsible for the salt demand of more than 70 million people in Sichuan, Kang, Yunnan, Guizhou, Hunan, Hubei and Shaanxi provinces. Zigong salt tax accounted for more than 80% of Sichuan salt tax revenue. Feng Yuxiang exclaimed that "it is the largest salt producer in the southwest, and its contribution to the country and the local area is amazing and magnificent."

Since the founding of the People's Republic of China, Zigong area has started to use modern technology to drill and make salt, and the production of well salt has achieved rapid development. The cumulative salt production is about 64.13 million tons, which exceeds the total salt production of Zigong in the 100 years before the founding of the People's Republic of China, accounting for one-third of the country's well salt production and two-thirds of the province's salt production.

▲In the 1930s, workers in Zigong who transported salt water were extremely tired and worked naked and sweaty. Photo by Sun Mingjing

07 Birth of a city

Looking at the history of the establishment of cities in my country, there are roughly two types. One is "building a city to protect the king and building a city wall to protect the people", such as Beijing, Nanjing, Xi'an, Chengdu, etc. The other is "gathering people for profit and building a city for people", such as Jingdezhen in Jiangxi, Foshan in Guangdong and Zigong in Sichuan.

The history of Zigong is the history of people gathering because of salt and the town being built because of people.

The discovery and mining of the "Fushi Salt Well" gathered a large number of salt workers, attracted many salt merchants, and also promoted the development of related industries. Ultimately, people gathered because of the benefits, and a town was established because of the people. The predecessor of Fushun County - Fushi County (renamed Fuyi County in the Tang Dynasty) was thus formed.

During the Northern and Southern Dynasties, the successful excavation of the Dagong Well directly gave birth to Gongjing Town (later changed to Gongjing County, Gongjing Town, and Gongjing Sub-County). Fushi County and Gongjing Town are the earliest administrative units in Zigong City and are also the prototype of Zigong City.

The Artesian Well, which was dug during the Jiaqing period of the Ming Dynasty, is another famous ancient well after the Fushi Salt Well and the Da Gong Well.

▲With the development of the salt industry, the division of labor in the Zigong Salt Field industry became increasingly detailed, wage labor became universal, commercial capital became active, and the joint-stock system emerged, thus giving birth to the embryonic form of capitalism in China. Photo by Sun Mingjing

After the Qing Dynasty, the two salt fields of Zi (Liujing) and Gong (Jing) "employed no less than 100,000 people in the salt industry, and there were tens of thousands of cattle and horses. It was truly the only large factory in our country."

Not only that, "all kinds of industries flocked here, so there was everything you could want", various "shops and wells and stoves were scattered around, connecting the village and the market, stretching for more than 40 miles", a city that prospered because of salt was about to emerge.

After the outbreak of the Anti-Japanese War, Zigong City was established based on Ziliujing and Gongjing due to the needs of the war and the second round of Sichuan salt transportation to Chu. After more than a thousand years of development and evolution, the Millennium Salt Capital has finally become what it is today.

▲The history of Zigong as a city based on salt is hidden in the ancient buildings of this city. The picture above is Xiqin Guild Hall. Photo by Miao Ziping

09 A unique culture with salt and flavor

The reason why Zigong Salt Field has been prosperous for thousands of years is that it has benefited from a large amount of export. To export salt, a developed transportation network is the key.

Therefore, taking Zigong Salt Field as the starting point, the ancient salt roads full of hardships and sweat either cross mountains and ridges or go against the river and cross the rapids, winding into the distance and extending to every corner where smoke rises.

Along these salt roads, we can see a series of docks including Xiantan, Huangnitan, Dengguan, Fushun County, Dongjie, Lijiawan, Pipachang, Anxi, Shihuixi, Zhaohua, Dacheng, Huaide and Changtan.

Wherever the dock is located, there is often an ancient town or a castle that has stood proudly despite the wind and rain. For example, there are more than 10 ancient towns on both sides of the waterway from Zigong to Luzhou, which is less than 200 kilometers long, including Xianshi, Shishi, Dengguan, Fushi, Pipa, Anxi, Zhaohua, Dacheng, Huaide, and Changtan.

▲Night view of Wangye Temple in Zigong City. Photo by Ni Wenhao (TuChong Creative)

Salt merchants were the most profitable industry in Zigong and even the whole country at that time. In order to "show off their county and hometown and express their hometown feelings", the salt merchants who made money established "hometown association halls". The association hall culture integrated foreign culture with local culture and became a beautiful color in Zigong culture.

The most famous guild halls include the Xiqin Guild Hall built by Shaanxi merchants, the Yuwang Palace built by the hometown associations of Hubei, Hunan and Jiangxi, the Jiyun Palace of the Guizhou Guild Hall, the Tianhou Palace of the Fujian Guild Hall, and the Nanhua Palace of the Guangdong Guild Hall.

The culture here is full of the flavor of salt, which is the unique crystallization of salt on this land. Legends, stories, poems, customs, festivals and celebrations are full of the strong flavor of salt; the names of ancient roads, waterways, bridges, streets, shops, mountains and stones are all closely related to salt; Sichuan opera is a unique Sichuan specialty, and Zigong's Sichuan opera always reflects the brilliance of salt culture; salt-flavored dishes are neither salty nor bland, which perfectly reflects the charm of salt culture and penetrates into people's daily lives, and also creates the reputation of "eating in Sichuan, tasting in Zigong".

▲Huanhou Palace. Photo by Miao Ziping

Zigong lanterns have a history of more than 800 years. They were finalized during the Ming and Qing Dynasties when salt mining was at its most prosperous. They eventually became famous throughout the ages and won the title of "the best lantern in the world."

The Zigong Lantern Festival is famous for its grandeur and scale; its ingenious conception and exquisite production; and its blending of lights and scenery and its mystical layers.

Every year around the Spring Festival, this place becomes a sea of ​​lights, and tourists from far away drive here to see the lights. Zigong lanterns have become another business card of Zigong after dinosaurs and well salt.

▲Zigong Lantern Festival flourishes because of salt. Photo by Li Zhongdong

References: Li Zhongdong, Xing Lida, Zou Rong, "Legend of Salt Well, Hometown of Dinosaurs", Planet Map Press, 2014;