Map Introduction

Western Jin (266–316 AD)

The Western Jin was a unified dynasty in Chinese history following the Three Kingdoms period. Together with the Eastern Jin, it constitutes the Jin Dynasty. It had four emperors and lasted fifty-one years. If counting from the conquest of Eastern Wu, its effective duration was merely 37 years. To distinguish it from the Eastern Jin and Later Jin, historians refer to it as the Western Jin, with both Western and Eastern Jin collectively known as Sima Jin.

Historical Evolution of Western Jin (266–316 AD)

Establishment and Unification - Rise of the Sima Clan: In the late Cao Wei period, Sima Yi seized control of the government through the Gaoping Tomb Incident (249 AD), eliminating the Cao Shuang faction. His son Sima Shi deposed Wei Emperor Cao Fang, and Sima Zhao had Cao Mao assassinated. Finally, Sima Yan forced Cao Huan to abdicate in 265 AD, establishing the Western Jin with its capital at Luoyang. - Conquest of Wu and Unification: In 279 AD, Sima Yan launched a six-pronged campaign against Eastern Wu. Wang Jun's naval forces directly captured Jianye, and in 280 AD, the Wu ruler Sun Hao surrendered, ending the Three Kingdoms division. After unification, the Land Occupation System and the Tax-Field System were implemented, leading to the Taikang Era of Prosperity (280–289 AD), during which the population recovered to 16 million.

Political System and Governance Crisis - Drawbacks of the Enfeoffment System: Emperor Wu of Jin enfeoffed 27 princes of the imperial surname, granting them extensive military and administrative powers in an attempt to counterbalance powerful families. However, this led to the regional princes becoming overly powerful. - Rigidity of the Nine-Rank System: Aristocratic families monopolized official careers, resulting in a situation where "high ranks had no candidates from poor families, and low ranks had no candidates from powerful clans." - War of the Eight Princes (291–306 AD): During the reign of Emperor Hui of Jin, Jia Nanfeng's interference in politics triggered a devastating civil war among the imperial clan. Prince Zhao Sima Lun usurped the throne, and the princes attacked each other, resulting in hundreds of thousands of deaths and exhausting the state's strength.

Social and Ethnic Conflicts - Migration of the Five Hu Groups: From the Eastern Han through the Western Jin, ethnic groups such as the Xiongnu, Xianbei, Jie, Di, and Qiang migrated into areas like Shanxi and Shaanxi, living intermingled with the Han Chinese. - Extravagance and Corruption: In his later years, Emperor Wu of Jin indulged in pleasure, maintaining a harem of nearly ten thousand women. The aristocracy was steeped in extravagance, intensifying social contradictions.

Collapse and Impact - Yongjia Disaster (311 AD): Liu Yuan of the Xiongnu established the Han state, captured Luoyang, and took Emperor Huai of Jin prisoner. Scholar-official families migrated south in large numbers, an event known as the "Movement of the Gentry South." - Fall of Western Jin (316 AD): Emperor Min of Jin was captured, Chang'an fell, and the Western Jin collapsed, ushering in the Period of the Five Hu and Sixteen Kingdoms.

Historical Evaluation Although the Western Jin unified China, internal strife, flawed ethnic policies, and corrupt governance rendered it one of the "weakest unified dynasties." Its brief unification set the stage for the aristocratic dominance of the Eastern Jin and the ethnic integration of the Northern and Southern Dynasties.