Emperor Yang digs the Grand Canal

The Sui had reunited China in 589, but its capital lay in the north-west, far from the rich farmlands of the lower Yangtze, and Emperor Wen had already begun to restore the old waterways. In the spring of 605, the first year of his Daye era, Emperor Yang ordered a new Eastern Capital to be built at Luoyang, and on 14 April, according to the Book of Sui, he called up more than a million men and women of the commanderies south of the Yellow River to dig the Tongji canal: from the palace park at Luoyang to the Yellow River, and from Banzhu on the Yellow River to the Huai. The Zizhi tongjian adds that over 100,000 people of Huainan reopened the old Hangou canal from Shanyang to the Yangtze, that the canal was forty paces wide with an imperial road lined with willows along its banks, and that more than forty travelling palaces were built between Chang’an and Jiangdu; on the works of the Eastern Capital, it says, the overseers drove the conscripts so hard that four or five in ten died. In October the emperor sailed to Jiangdu, modern Yangzhou, in a four-decked dragon boat, followed by a flotilla which, the chroniclers claim, stretched for over 200 li and was hauled by more than 80,000 men.

On New Year’s Day 608 (23 January) the emperor ordered the Yongji canal, which led the Qin River south to the Yellow River and north to Zhuo commandery near modern Beijing. The Book of Sui again speaks of more than a million men and women from the commanderies north of the river; the Zizhi tongjian of more than five million, adding that, as there were not enough men, women were conscripted for the first time. The same chronicle records under the twelfth month of the sixth Daye year — January or February 611 — an order to dig the Jiangnan canal from Jingkou (Zhenjiang) to Yuhang (Hangzhou), over 800 li long and wide enough for the dragon boats. In April–June 611 the emperor travelled by boat from Jiangdu through the canals to Zhuo, the base for his war against Goguryeo, and grain and weapons were shipped north along the same route in fleets which, the chronicle says, stretched for a thousand li, while the dead lay by the roads.

Modern accounts usually date the main works to 605–609 or 605–610. The historians blamed the labour levies and the wars for the rebellions that destroyed the Sui in 618, and later tradition remembered Emperor Yang as a tyrant; but the waterway linking the north with the Yangtze valley proved enormously valuable to the Tang and, rebuilt and re-routed by later dynasties, served from the Tang to the Qing as the main artery between north and south China. The Grand Canal was inscribed on the UNESCO World Heritage List on 22 June 2014.