Grand Canal of China: Emperor Yang's Great Waterway (605)

The Grand Canal of China is the world’s longest artificial waterway, and its first continuous form was created by the Sui dynasty between 605 and 610 under Emperor Yang. By linking existing rivers and older canals with huge new cuts, the Sui joined the Yellow River and the Yangtze, the two great river systems of China, into a single transport network. Built at enormous human cost, the canal carried the grain of the south to the capitals of the north for more than a thousand years and remains in partial use today.

Background: why China needed a canal

China’s main rivers flow from west to east, so travel between the north and south was difficult. After the Sui reunification of China in 589, the political centre lay in the north, around Chang’an and Luoyang, while the fastest-growing farmland was in the rice-producing lower Yangtze region. Feeding the capitals and the frontier armies meant moving millions of bushels of grain hundreds of kilometres.

Canal building in China was already ancient. In 486 BC King Fuchai of Wu dug the Han Gou, linking the Yangtze to the Huai River, and in 214 BC the Qin dynasty built the Lingqu Canal to connect the Yangtze and Pearl River systems. Many short canals and improved river channels existed in the north and south, but they had never been joined into a coherent network.

The founder of the Sui, Emperor Wen, began the work. In 584 the engineer Yuwen Kai built the Guangtong Canal, more than 150 km long, alongside the silt-laden Wei River to bring grain from the Yellow River to the new capital Daxing (Chang’an). In 587 the old Han Gou route between the Huai and the Yangtze was reopened as the Shanyang Canal to support the coming war against the southern Chen dynasty.

Emperor Yang’s great project

Emperor Yang (Yang Guang), who took the throne in 604, turned these local works into an empire-wide system. Almost immediately he began building a new eastern capital at Luoyang, which was to be the hub of the canal network.

The Tongji Canal (605)

In the spring of 605 the emperor ordered the construction of the Tongji Canal, running from the Luoyang area to the Yellow River and then south-east across the plains of modern Henan and Anhui to the Huai River. The Book of Sui records that more than a million men and women from the regions south of the Yellow River were conscripted. At the same time the Shanyang (Han Gou) section was rebuilt with over 100,000 labourers, giving a continuous route to the Yangtze at Jiangdu (modern Yangzhou).

According to the Sui histories, the canal was built with an imperial road along its banks, lined with willow trees. The work was completed within about half a year, and in the autumn of 605 the emperor sailed to Jiangdu with a vast fleet of dragon boats and barges, a display of power that later historians remembered as an example of extravagance.

The Yongji Canal (608)

In 608 Emperor Yang ordered a northern arm, the Yongji Canal, from the Yellow River near Luoyang to Zhuojun, close to modern Beijing. Its purpose was largely military: Zhuojun was the base for the campaigns against the Korean kingdom of Goguryeo. The Book of Sui states that more than a million people were drafted from the regions north of the Yellow River and that, because there were not enough men, women were also conscripted.

The Jiangnan Canal (610)

The final major section, the Jiangnan Canal, was dug in 610 from Jingkou (modern Zhenjiang) on the south bank of the Yangtze to Yuhang (Hangzhou). It linked the canal network to the wealthy lands around Lake Tai and the coast.

The finished system

The Sui canals formed a Y-shaped network with its centre at Luoyang. One arm ran north-east to the Beijing area, the other south-east through the Huai valley to the Yangtze and Hangzhou. Including river sections and older canals, the whole system is usually estimated at roughly 2,000 to 2,700 km, although figures vary according to what is counted.

Most of the route crossed flat alluvial plains, so engineers relied on gentle gradients, natural rivers and simple gates and slipways rather than complex locks. Huge state granaries, such as the Luokou and Huiluo granaries near Luoyang, were built at key points to store the grain arriving by water.

The human cost

The canal is inseparable from the reputation of Emperor Yang. Labour service was owed by ordinary households, and the scale of conscription in 605 and 608, at the same time as the building of Luoyang, palaces and repairs to the Great Wall, placed an extreme burden on the population. The Sui histories describe heavy losses among the workers, but they give no reliable total, and modern historians do not accept any precise death toll.

Burdens grew worse when the canal was used to supply the three Goguryeo wars of 612–614, including the disastrous Battle of Salsu. Rebellions spread across the empire, and in 618 Emperor Yang was murdered by his own officers at Jiangdu, the canal city he had favoured. Chinese tradition long treated him as the model of a tyrant, though modern historians also stress the lasting value of his public works.

Myths and facts

A popular tradition, repeated in later novels and plays, holds that Emperor Yang dug the canal mainly so that he could travel in luxury to Jiangdu and enjoy its scenery. His lavish tours by dragon boat were real and were heavily criticised by Tang historians, who had every reason to blacken the reputation of the dynasty they replaced. The canal’s main purposes, however, were practical: moving tax grain, supplying armies and binding the newly conquered south to the north.

Another common simplification is that the Sui built the Grand Canal from nothing. In reality Sui engineers reused and widened many older waterways, some more than a thousand years old, and combined them with long new channels. The achievement lay in planning and joining these pieces into a single system in a few years.

Finally, the canal seen by travellers today is not the Sui canal. Much of the Sui route through Henan and Anhui silted up after the Song period and survives only as buried channels and archaeological sites, such as the excavated stretches at Sui County in Henan. The modern Beijing–Hangzhou line follows the later Yuan, Ming and Qing route, although its southern sections around Yangzhou, Zhenjiang and Hangzhou still follow Sui alignments.

Key people

• Emperor Wen of Sui (r. 581–604): began the canal works with the Guangtong and Shanyang canals.
• Yuwen Kai (555–612): leading Sui engineer and architect, who directed the Guangtong Canal and the planning of Daxing and Luoyang.
• Emperor Yang of Sui (r. 604–618): ordered the Tongji, Yongji and Jiangnan canals and gave the system its final form.

Later history

The Tang dynasty (618–907) relied heavily on the Sui canals. Grain transported from the south fed the capital Chang’an, and when shipments failed the court sometimes had to move temporarily to Luoyang. Under the Song dynasty (960–1279) the capital Kaifeng lay on the Bian Canal, the former Tongji route, and its prosperity depended on canal traffic. In 984 the Song official Qiao Weiyue built a double-gated pound lock on the canal, an early example of a technology that later became standard worldwide.

The modern course of the canal dates largely from the Yuan dynasty. After the Mongols made Dadu (Beijing) their capital, new canals in Shandong, including the Huitong Canal (1289), and the Tonghui Canal at Beijing (1293) created a much more direct north–south route that bypassed Luoyang. The Ming rebuilt the Shandong section in 1411, and the canal remained the empire’s main grain artery into the 19th century.

Decline came when the Yellow River changed its course in 1855, cutting the canal in Shandong, and when steamships and railways replaced inland grain transport. Southern sections, however, never stopped carrying cargo. In 2014 the Grand Canal was inscribed on the UNESCO World Heritage List, and parts of it now form the eastern route of a project that transfers water from the Yangtze to northern China.

By the numbers

Timeline

• 486 BC: King Fuchai of Wu digs the Han Gou between the Yangtze and the Huai.
• 584: Emperor Wen’s Guangtong Canal links the Sui capital with the Yellow River.
• 587: The Shanyang Canal is opened between the Huai and the Yangtze.
• 605, spring: Emperor Yang orders the Tongji Canal; over a million workers are conscripted.
• 605, autumn: The emperor sails to Jiangdu along the new waterway.
• 608: Work begins on the Yongji Canal to the Beijing area.
• 610: The Jiangnan Canal to Hangzhou completes the Sui system.
• 1289–1293: Yuan dynasty canals create a direct route to Beijing.
• 1855: A shift in the Yellow River’s course breaks the canal in Shandong.
• 2014: The Grand Canal becomes a UNESCO World Heritage Site.

Why it matters

The Grand Canal tied the economic south of China to the political north and helped keep the country united for centuries. Its story also shows the double face of great state projects: a lasting benefit for later generations, paid for by the forced labour of millions in its own time.