Luan Gongshu 欒共叔 Luan Cheng 欒成

Luan Cheng 欒成 (died 709 BCE), personal name Ji Cheng 姬成, posthumous title Luan Gongshu 欒共叔 or Luan Gongzi 欒共子, was a nobleman in the state of Jin 晉 during the Spring and Autumn period 春秋 (770-5th cent. BCE).

He was a son of Luan Bin 欒賓, tutor to Huanshu 桓叔 (r. 745-732) of Quwo 曲沃 and founder of the house of Luan 欒. Luan Cheng himself was tutor to Marquis Ai of Jin 晉哀侯 (r. 717-677).

In 709, Duke Wu of Quwo 曲沃武公 (r. 717-677) attacked Ji 翼 (near modern Jicheng 翼城, Shanxi), the capital of Ji, and killed Marquis Ai. Luan Cheng was the only nobleman of Jin who criticized Duke Wu for the murder of the righteous ruler of Jin. He also refused to cooperate with the usurper and died, fighting for the just order in the dukedom.