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Duan Yu, courtesy name Heyu, temple name Xianzong, posthumous name Emperor Xuanren, was the 16th emperor of the Dali Kingdom between 1108 and 1147. Following a family tradition, Duan's father, Duan Zhengchun, abdicated and became a monk in 1108. Duan succeeded his father as the emperor of Dali and renamed himself Duan Zhengyan. He abdicated and became a monk in 1147 and was succeeded by his son Duan Zhengxing.
- If Gao Shengtai's reign is taken into consideration, Duan Yu would have been the 17th emperor. See .