The Yanzhi River Cut Through the Hills in the Ming

Background

With the Ming capital at Nanjing, the tax grain of the Zhejiang region had to reach the capital. Neither water route worked well: on one, boats had to be unloaded at Danyang and the cargo carried overland; on the other, upstream on the Yangtze, winds and waves sank many vessels. In the eighth month of 1393, the twenty-sixth year of the Hongwu era, the founding emperor sent the Marquis of Chongshan, Li Xin, to Lishui to supervise the cutting of a river through the western part of the county and so connect the water routes. The Kangxi edition of the Lishui County Gazetteer (卷之一·邑纪) preserves the gist of the order: the grain tribute of the two Zhejiang circuits cost enormous sums to ship to the capital, and the emperor wished to open a waterway from the capital region through to Zhejiang so that "those who transport need not toil, and merchants and travellers may find it convenient" — charging Li Xin to be diligent and not to treat the labourers harshly.

Time and place

Both the gazetteer and official accounts date the main excavation to 1393. The work ran through the Yanzhi Hill in the western part of the county. The channel ran from the mouth of the Qinhuai River in the north to Honglan Wharf and into Shijiu Lake in the south, about 7.5 kilometres long. Because the rock cut through was red, the river was called Yanzhi — "rouge".

The work

The geology was difficult and the rock hard. The gazetteer notes that the stone cut was red; the Jiangsu Provincial Department of Culture and Tourism describes the method as "burning the rock to cut the river" over a stretch of fifteen li. On the scale of the mobilisation, the Nanjing Municipal Water Resources Bureau records more than 750,000 labourers and over 1,400 officials at the peak; the provincial account says several hundred thousand labourers. Along the line, a natural boulder arched across the gorge between the two cliffs. Instead of removing it, the builders left it in place as a bridge — the Tiansheng Bridge. There were originally two, north and south; the south bridge collapsed in the spring of 1528 and only the north one survives.

Consequences

Once open, the channel gave a direct water route between the Qinhuai River and Shijiu Lake. Grain from the Zhejiang region no longer had to be carried overland, and trade traffic benefited. The river long carried grain transport and general traffic, and settlements and granaries grew up along it — the rebuilding of the public granary by the magistrate He Yigui in 1567 belongs to the same river-transport system. The Tiansheng Bridge is the only known surviving example of a bridge formed from the two banks of a man-made canal by leaving a boulder in place. It is now protected together with the Yanzhi River as one provincial site, within the Tiansheng Bridge scenic area, a 4A-rated tourist attraction.

Uncertainties

First, the duration is reported inconsistently. The provincial culture and tourism department says the work took "more than ten years"; the municipal water resources bureau says it began in 1391, the twenty-fourth year of the Hongwu era, and was completed in "nearly five years". The difference may reflect the main excavation against the full works including the sluices, but no source makes that distinction, so this entry presents both without choosing between them. The confidence level is therefore set to medium.

Second, the fate of Li Xin, who supervised the work. The gazetteer says that "it is handed down that Li Xin took private advantage of a household, and the founding emperor put him to death", prefacing the story with "it is handed down". It is a tradition, not an established fact. This entry repeats it with that qualifier intact. The wider analysis is in "Dating the Yanzhi River and Its Method of Excavation".