Niu Jin was a general active from the late Eastern Han period into Cao Wei.[2][1]
Battle of Jiangling
After Cao Cao pacified Jing Province, Niu Jin was stationed at Jiangling under Cao Ren. When Zhou Yu's forces attacked, Niu Jin was surrounded while leading the defense and was rescued after Cao Ren led troops to break the encirclement.[2]
Service under Sima Yi
Niu Jin later served under Sima Yi. In 235 he repelled the Shu general Ma Dai; in 238 he was appointed General of the Rear and joined the expedition against Gongsun Yuan.[2]