The Ancient Tea Horse Road or chamagudao was a network of caravan paths used as a tea delivery route. It winded its way through the mountains of Sichuan, Yunnan and Tibet in Southwest China.
Sichuan and Yunnan are believed to be the first tea-producing regions in the world. The first record of tea cultivation in the world suggested that tea was cultivated on Sichuan's Mount Mengding between Chengdu and Ya'an earlier than 65 BC. Ya'an has been an important hub of tea trading till the 20th century. Besides tea, silk products from Chengdu, notably Shujin, was also traded through this road to South Asian from around 2000 years ago.
From around a thousand years ago, the Tea Horse Road was a trade link from Yunnan to Bengal via Myanmar to Tibet and to Central China via Sichuan Province. In addition to tea, the mule caravans carried salt. Both people and horses carried heavy loads, the tea porters sometimes carrying over 60–90 kg, often more than their own body weight in tea. The porters carried metal-tipped staffs, both for balance while walking and to help support the load while they rested, so they didn't need to lay the bales down.
It is believed that it was through this trading network that tea (typically hard-dried tea bricks) first spread across China and Asia from its origins in Pu'er county, near Simao Prefecture in Yunnan.
The route earned the name Tea-Horse Road because of the common trade of Tibetan ponies for Chinese tea, a practice dating back at least to the Song dynast, when the sturdy horses were important for China to fight warring nomads in the north.
Pu'er or pu-erh is a variety of fermented tea produced in the Yunnan province of China. Fermentation in the context of tea production involves microbial fermentation and oxidation of the tea leaves, after they have been dried and rolled. This process is a Chinese specialty and produces tea known as heichá (literally, 'black tea') commonly translated as 'dark tea'. This type of tea is different from what is known as black tea in English, which in Chinese is called hóngchá or red tea.
Pu'er is typically made through two steps. First, all leaves must be roughly processed into maocha to stop oxidation. From there it may be further processed by fermentation, or directly packaged.
To produce pu'er, many additional steps are needed prior to the actual pressing of the tea. First, a specific quantity of dry máochá or ripened tea leaves pertaining to the final weight of the bingcha is weighed out. The dry tea is then lightly steamed in perforated cans to soften and make it more tacky. This will allow it to hold together and not crumble during compression. A ticket, called a nèifei or additional adornments, such as colored ribbons, are placed on or in the leaves and inverted into a cloth bag or wrapped in cloth. The pouch of tea is gathered inside the cloth bag and wrung into a ball, with the extra cloth tied or coiled around itself. This coil or knot is what produces the dimpled indentation at the reverse side of a tea cake when pressed. Depending on the shape of the pu'er being produced, a cotton bag may or may not be used.
Pu'er is compressed into a variety of shapes. Other lesser seen forms include stacked 'melon pagoda', 'pillars', calabashes, yuanbao and small tea-bricks (2–5 cm in width). Pu'er is also compressed into the hollow centres of bamboo stems or packed and bound into a ball inside the peel of various citrus fruits.
The best known pu'er areas are the Six Great Tea Mountains, a group of mountains in Xishuangbanna, Yunnan. This region is renowned for its differing micro-climates and environments, which not only provide excellent growing conditions for pu'er, but also produce unique taste profiles (akin to terroir in wine).
The legacy of the Tea-Horse Road is now being used to promote a railway that will connect Chengdu to Lhasa. The planned Sichuan-Tibetan railroad, part of the China's 13th 5-Year Plan, connecting cities across the route including Kangding.