Sui Dynasty Reunification of China (589): End of Division

The Sui dynasty reunification of China was the conquest of the southern Chen dynasty by the northern Sui state in the winter of 588–589, which brought all of China proper under a single ruler for the first time in about 270 years. Its architect, Yang Jian, known as Emperor Wen of Sui, combined a well-planned military campaign with sweeping administrative reforms. Although the Sui lasted only until 618, the unified state it created became the foundation of the Tang dynasty and of every major Chinese empire that followed.

Background: three centuries of division

The last time China had been united was under the Western Jin dynasty, which had itself ended the Three Kingdoms period with the Jin reunification of 280. That unity collapsed within a generation. Civil war among Jin princes was followed by invasions from northern peoples, and after the fall of the capitals Luoyang (311) and Chang’an (316) the Jin court survived only south of the Yangtze River.

For the next two and a half centuries, China was split. The north was ruled by a succession of states, many founded by non-Chinese groups such as the Xianbei, the most important being the Northern Wei (386–534). The south was governed from Jiankang, modern Nanjing, by a series of short-lived Chinese dynasties: the Eastern Jin, Liu Song, Southern Qi, Liang and finally the Chen (557–589). Historians call this the era of the Northern and Southern Dynasties.

The two halves developed differently. The south preserved the court culture of the old Han and Jin elites and grew rich from rice farming and trade, while the north mixed Chinese and steppe traditions and built strong military institutions. By the 570s the north held the advantage: in 577 the Northern Zhou state conquered its rival Northern Qi, reuniting northern China and leaving Chen as the only independent power.

The rise of Yang Jian

Yang Jian (541–604) came from an aristocratic family of mixed Chinese and northern military background that served the Northern Zhou. His father had been made Duke of Sui, a title Yang Jian inherited, and his eldest daughter married the Zhou crown prince, who became Emperor Xuan.

When Emperor Xuan died in 580, leaving a young son, Yang Jian made himself regent. He crushed a rebellion by the general Yuchi Jiong and other Zhou loyalists within months. In early 581 he forced the child emperor to abdicate and proclaimed the Sui dynasty, taking the reign title Kaihuang (“Opening Splendour”). Members of the Zhou imperial Yuwen clan were put to death, a ruthless act that removed rival claimants.

Preparing for the conquest

Emperor Wen did not attack the south at once. For several years he concentrated on securing his northern frontier against the Turks (Tujue), building a new capital and reorganising the government. He also gathered intelligence on the Yangtze defences and, according to traditional accounts, harassed Chen by staging repeated false alarms at harvest time so that the southerners would stop reacting to troop movements.

In 587 the Sui abolished the small dependent state of Later Liang at Jiangling on the middle Yangtze, gaining a base upstream of the Chen heartland. Large fleets were built in Sichuan and along the river. Meanwhile the Chen court, under its last ruler Chen Shubao (r. 582–589), was weakened by factional politics; later historians portrayed him as more interested in poetry and palace entertainments than in defence, a picture coloured by the Sui’s own propaganda but broadly accepted.

The campaign of 588–589

In the winter of 588 the Sui launched a coordinated offensive along the whole Yangtze front. The Book of Sui gives the total force as 518,000 men, a figure that may include support troops and should be treated as an approximation. Nominal supreme command went to the emperor’s second son Yang Guang, the Prince of Jin, while the senior minister Gao Jiong directed operations in practice.

The general Yang Su sailed down the Yangtze from Sichuan with a large war fleet, defeating Chen river forces and pinning down their armies in the middle Yangtze. Downstream, two commanders, He Ruobi and Han Qinhu, crossed the river near Jiankang at the start of the lunar new year in 589, when Chen defences were least alert. He Ruobi crossed from Guangling (near modern Yangzhou), and Han Qinhu crossed at Caishi, south-west of the capital.

The Chen army fought one major battle outside Jiankang and was defeated. Han Qinhu’s troops entered the city first. Chen Shubao was found hiding in a palace well with two of his consorts and was taken prisoner. Most remaining Chen commanders surrendered on his written orders, and the southern provinces were occupied during 589. Uprisings in the south in 590 were put down by Yang Su.

Key people

• Yang Jian (Emperor Wen, r. 581–604): founder of the Sui; a hard-working, frugal and suspicious ruler who personally reviewed great numbers of state documents.
• Empress Dugu (Dugu Qieluo): his influential consort, who took part in decisions and strongly shaped the succession.
• Gao Jiong: chief minister and the main planner of the conquest and of many reforms.
• Yang Su: general who led the Yangtze fleet and later suppressed southern revolts.
• Yang Guang: the emperor’s son and nominal commander in 589, who became Emperor Yang in 604.
• Chen Shubao: the last ruler of Chen, who spent his final years as a captive in the Sui capital and died in 604.

Rebuilding a united state

Conquest alone would not have lasted without the reforms that accompanied it. Emperor Wen issued a new law code, the Kaihuang Code (581, revised 583), which simplified punishments and later served as a model for the Tang Code. The central government was organised into three departments and six ministries, a structure used by later dynasties for well over a thousand years.

Local administration was streamlined in 583 by abolishing one layer of government, the commanderies, and the number of local units was cut. Officials were barred from serving in their home districts, and new recruitment methods were tried that later developed into the imperial examination system. Censuses were tightened to bring hidden households onto the tax registers, and the equal-field system, which allocated land to farming households in return for taxes and labour service, was continued.

The emperor also built a new capital, Daxing, beside the ruins of Han-dynasty Chang’an, which the Tang would later rename and make famous as Chang’an. State granaries were set up to store tax grain, and canals were dug to move it to the capital. Emperor Wen was a devout patron of Buddhism, and in 601–604 he sent relics to more than a hundred prefectures, where stupas were built at state expense, using shared religion to bind the regions together.

Jiankang itself paid a price. On imperial orders its palaces and walls were demolished and the city reduced in status, a deliberate attempt to stop the old southern capital from becoming a focus of resistance.

Consequences and the fall of the Sui

The reunification gave the Sui control over a population that its own census around 609 recorded at about 46 million people in roughly 9 million households, making it one of the largest states in the world. Southern rice and northern military power were now under one government.

The new emperor, Yang Guang, who succeeded in 604 amid rumours that he had hastened his father’s death, used these resources on a vast scale. He built a second capital at Luoyang and the Grand Canal linking the Yellow River and the Yangtze. He also launched three invasions of the Korean kingdom of Goguryeo in 612, 613 and 614. The first ended in disaster at the Battle of Salsu.

The cost in labour, lives and taxes provoked widespread rebellion. Emperor Yang withdrew to Jiangdu (Yangzhou), where he was murdered in 618. The same year Li Yuan, a Sui general and relative of the imperial family by marriage, founded the Tang dynasty.

Legacy

The Sui is often compared with the Qin dynasty of the 3rd century BC: both reunified China after a long period of division, both ruled for less than four decades, and both were remembered by their successors as harsh. In each case, however, the next dynasty kept most of their achievements. The Tang inherited the Sui capital, law code, administrative system, canals and granaries, and built the brilliant Tang golden age on those foundations.

Since 589 China has experienced further periods of division, but the idea that it should be a single state has never again been seriously abandoned. In that sense Emperor Wen’s conquest of Chen is one of the turning points of East Asian history.

Timeline

• 577: Northern Zhou conquers Northern Qi, reuniting northern China.
• 580: Yang Jian becomes regent of Northern Zhou and suppresses a loyalist revolt.
• 581, early in the year: Yang Jian takes the throne and founds the Sui dynasty.
• 582–583: The new capital Daxing is built and occupied; local administration is reorganised.
• 587: Sui abolishes the dependent Later Liang state at Jiangling.
• 588, winter: Sui armies and fleets advance along the Yangtze.
• 589, early in the year: Sui forces cross the Yangtze and capture Jiankang; Chen Shubao is taken prisoner.
• 604: Emperor Wen dies and Yang Guang becomes Emperor Yang.
• 618: Emperor Yang is murdered and the Tang dynasty is founded.

Why it matters

The conquest of Chen in 589 ended nearly three centuries of division between northern and southern China. Together with Emperor Wen’s reforms, it created the institutional and economic framework on which the Tang, and later Chinese states, were built.