The Tuman River winds its way around the 40-meter loess mound in the ancient Silk Road city of Kashgar in the Xinjiang Uygur autonomous region in Northwest China. Local legend says that 800 years ago, a great flood carried massive amounts of clay down the river, settling on the banks outside the city.
The ingenious locals, seeking to make the most of the newly abundant resource, established Kashgar's first pottery workshops on the mound. And so, the "kozichi yar beshi" were born, or "potter families of the mound".
The history of pottery in Kashgar dates back thousands of years, as evidenced by a large number of ceramic artifacts including jars, bowls, basins, plates and cups having been unearthed from a Neolithic archaeological site, about 50 kilometers from the city.
Tursun Zunun is a sixth generation potter whose family had prospered in the ceramic trade for centuries, establishing a rich culture and tradition surrounding its unique crafting methods.
In 2006, Kashgar pottery was included in China's first list of intangible cultural heritage.
Apart from ensuring ceramics from Kashgar were made with the best quality clay, Zunan, 60, said that there are three rules central to the tradition - only family members can be taught the craft, no using modern tools and only men can be taught.
Zunun still manually rotates a wooden wheel from the balcony of his workshop, from which he can today see a giant Ferris wheel standing among modern buildings in the distance.
The wheel in Zunun's workshop is made of desert poplar wood. Instead of an electric motor, he uses his feet to rotate the wheel, and pulls the clay gently upward and outward to create desired shapes.
After painting and glazing, Zunun places the clay into a straw-fired kiln and fires it at 900 C for seven hours. Once complete, the molded piece of mud is transformed into a delicate artwork with simple dark brown patterns and a khaki glaze.
The rise of modern technology has proved challenging for the city's ceramics industry. Once a vital material, ceramics are today challenged by metals and plastics mass-produced more cheaply on an industrial scale.
As such, the traditional industry has suffered. Where once there were hundreds of potteries on the mound, now only a few families remain, and Zunan has been forced to compromise on some of the rules passed down through the generations.
Traditional Kashgar pottery prospers with progression
"My three daughters are married and my only son went to the police academy," Zunun said. "No one in my family wanted to learn. So I advertised outside for apprentices."
To his surprise, two students from South Korea arrived at his door, having heard about Kashgar pottery.
"I don't mind breaking this rule, teaching the skills to strangers," Zunun said. "I have even given them Uygur names, Yishajan and Yumitijan."
The lure of a better income in the city has been too strong for many. Even Zunan took up a job there for several years before returning home after his father became too old to carry on the family tradition.
The fortunes of the industry took a turn for the better in 2006, with Kashgar pottery being announced as a Chinese intangible cultural heritage.
As an inheritor of this heritage, Zunun was provided with an annual subsidy of 4,800 yuan ($760) from the government.
To save the craft, the local government also worked with tourism agencies to help turn a part of Zunun's workshop into an exhibition area open to tourists.
More tourists have started to visit Kashgar as a result of a renovation project launched in 2009 to protect its old town. Xinjiang saw a record number of 107 million tourists in 2017.
Zunun's pottery in particular has proved popular with tourists, especially those from Japan and South Korea.
In 2015, another of his apprentices persuaded him to upgrade to an electric kiln, as they are more efficient and cause less harm to the environment.
"Now I'm breaking another rule," Zunan said. "I will teach whoever wants to learn, even if they use modern tools."
The third rule - the teaching of the craft only to men - was also recently defied.
Zunun's youngest daughter Iminhan returned home to study the family craft.
"She is well on her way to being the first female potter in Kashgar. I'm happy that she is going to carry on my legacy," Zunan said.
"In the past, pottery making was just the livelihood for my family. But now it is more than that to me. It is a part of all of our history that we must preserve."