Jin Reunification of China (280): The End of the Three Kingdoms

The Jin reunification of China was the conquest of the southern kingdom of Wu by the Western Jin dynasty in AD 280, which ended the Three Kingdoms period and brought China under a single ruler for the first time in about sixty years. It was the culmination of a long rise by the Sima family, who first took control of the state of Wei, then conquered Shu in 263 and finally crossed the Yangtze. The unity they built proved short-lived, but the events of 280 closed one of the most famous chapters in Chinese history.

Background: the Three Kingdoms

After the Han dynasty lost real authority in the late 2nd century AD, China fragmented among warlords. Following defeats such as the Battle of Red Cliffs in 208, three states emerged: Wei in the north, founded in 220 by Cao Pi; Shu Han in the south-west, under Liu Bei; and Wu in the south-east, under Sun Quan.

Wei was by far the largest and most populous of the Three Kingdoms, but the mountains of Sichuan and the broad Yangtze protected its rivals. Repeated campaigns in both directions, including the Northern Expeditions of Zhuge Liang, ended in stalemate.

The Sima clan takes over Wei

The decisive change happened inside Wei. Sima Yi, a senior general and minister who had fought Zhuge Liang, was named co-regent for the young emperor Cao Fang. In 249 he staged a coup while his rival, the regent Cao Shuang, was away from the capital Luoyang visiting the imperial tombs. Cao Shuang and his supporters were executed, and the Sima family became the real rulers of Wei.

Sima Yi died in 251. His sons Sima Shi and Sima Zhao kept control, crushing several rebellions by loyalists of the Cao family. In 260 the emperor Cao Mao tried to lead an attack on Sima Zhao himself and was killed by soldiers in the street, an episode that showed how little power the Wei throne still held.

The conquest of Shu and the new dynasty

In 263 Sima Zhao sent armies against Shu. While the general Zhong Hui held the main Shu army in the mountain passes, Deng Ai led a force along a difficult route through the mountains and appeared before Chengdu. The Shu emperor Liu Shan, son of Liu Bei, surrendered late in 263.

Zhong Hui then plotted to rule Sichuan himself in early 264, but the revolt collapsed and both he and Deng Ai were killed in the turmoil. Shu nevertheless remained in Wei hands, leaving Wu as the only independent rival.

Sima Zhao had been made King of Jin, the last step before a change of dynasty. He died in 265, and his son Sima Yan inherited the title. At the end of 265, a date usually given as February 266 in the Western calendar, Sima Yan made the last Wei emperor, Cao Huan, abdicate in his favour. He proclaimed the Jin dynasty with its capital at Luoyang and is known to history as Emperor Wu of Jin.

The new dynasty is called the Western Jin to distinguish it from the later Eastern Jin, which ruled from the south after 317.

The fall of Wu (279–280)

Wu had been weakened by succession disputes after the death of Sun Quan in 252. Its last ruler, Sun Hao, who came to the throne in 264, is remembered in the histories as cruel and erratic, although those histories were written by the victors and may exaggerate.

On the Jin side, the frontier commander Yang Hu argued for years that Wu could be conquered and prepared the ground, but he died in 278. His successor Du Yu and the official Zhang Hua pressed the emperor to act. In Sichuan, Wang Jun spent several years building a large river fleet to sail down the Yangtze.

The offensive began in the winter of 279. Several armies, traditionally put at about 200,000 men in total, advanced on a front stretching from the middle Yangtze to the lower river. Du Yu took the key city of Jiangling. Wang Jun’s fleet descended the river, and according to the Book of Jin his men cleared Wu’s iron chains and underwater stakes, burning the chains with huge rafts loaded with torches.

Wu’s resistance collapsed quickly. Wang Hun defeated the main Wu field army north of the river, and Wang Jun’s ships reached Jianye, the Wu capital on the site of modern Nanjing. In the spring of 280 Sun Hao surrendered, reportedly appearing bound and bringing a coffin as a sign of submission. He was spared and given a noble title, and lived in Luoyang until his death in 284.

By the numbers

Historians stress that the registered figures count only taxable households and greatly understate the real population after decades of war and displacement.

Key people

• Sima Yi (179–251): Wei general and regent whose coup of 249 gave his family power.
• Sima Zhao (211–265): ruled Wei in all but name and directed the conquest of Shu.
• Sima Yan, Emperor Wu of Jin (236–290): founded the Jin dynasty and ordered the conquest of Wu.
• Du Yu (222–285): commander on the middle Yangtze, also known as a scholar of the Zuo Zhuan.
• Wang Jun (206–286): built and led the river fleet that reached Jianye.
• Sun Hao (242–284): last emperor of Wu.

Consequences

Emperor Wu tried to secure the reunited empire in two ways that later proved fatal. He reduced the regular forces in the provinces after the war, while giving imperial princes of the Sima family their own territories and armies. He hoped relatives would defend the dynasty, but they became rivals.

Emperor Wu died in 290. His heir, Emperor Hui, was widely described as unfit to rule, and struggles between the empress Jia Nanfeng and the princes led to the War of the Eight Princes (291–306). Princes used non-Chinese troops, including Xiongnu and Xianbei horsemen, in their civil wars. In 304 the Xiongnu leader Liu Yuan proclaimed his own state, and in 311 his successors sacked Luoyang in the Disaster of Yongjia. By 317 the Jin held only the south.

Legacy

The reunification of 280 was the only time between 220 and 589 that all of China’s heartlands were ruled by one dynasty. Its brevity made it a classic warning in Chinese political thought about the dangers of arming the ruling family’s princes and neglecting central forces.

Culturally, the Jin era produced the historian Chen Shou, a former Shu official whose Records of the Three Kingdoms became the standard history of the period. Centuries later, the 14th-century novel Romance of the Three Kingdoms, attributed to Luo Guanzhong, ends with the Jin conquest of Wu and opens with a famous line about empires long divided that must unite, and long united that must divide.

Timeline

• 249: Sima Yi seizes power in Wei in a coup against Cao Shuang.
• 260: The Wei emperor Cao Mao is killed after trying to overthrow Sima Zhao.
• 263, late: Liu Shan surrenders; Shu Han falls to Wei.
• 265, end (early 266 in the Western calendar): Sima Yan founds the Jin dynasty.
• 278: Death of Yang Hu, chief advocate of the war against Wu.
• 279, winter: Jin launches a multi-pronged offensive against Wu.
• 280, spring: Sun Hao surrenders at Jianye; China is reunited.
• 290: Death of Emperor Wu of Jin.
• 291–306: War of the Eight Princes.

Why it matters

The conquest of Wu in 280 ended the Three Kingdoms and showed that a divided China could be rebuilt by one dynasty. Yet within a generation the Western Jin had torn itself apart, opening nearly three centuries of division between north and south that lasted until the Sui reunification of 589.