Duke Ding of Jin (Chinese: 晉定公; pinyin: Jìn Dìng Gōng), personal name Ji Wu, was from 511 BC to 475 BC the duke of the Jin state.
[1] After the extermination of the Luan clan by Duke Ding's great-grandfather Duke Ping, the state of Jin had been dominated by the six powerful clans – Fan, Han, Zhao, Wei, Zhonghang, and Zhi.
The Fan and Zhonghang forces attacked Zhao, and the three other clans – Han, Wei, and Zhi – came to Zhao's defence and attacked Fan and Zhonghang, who were defeated and forced to retreat to the city of Zhaoge.
Seven years later, in 490 BC the combined Jin forces decisively defeated the Fan and Zhonghang clans, whose leaders Fan Jishe and Zhonghang Yin fled to the State of Qi.
[2] Duke Ding reigned for 37 years and died in 475 BC.