The antagonism between the two families broke out into the open in 1506 after Yoshikage NAGAO died in battle in Ecchu and was succeeded by Tamekage NAGAO; the Hachijo Uesugi family suffered a major blow in Echigo's Eisho War, during which Ryumatsu HACHIJO, the governor of Owari, and his son, as well as Narisada UESUGI, were driven to take their own lives.
永正3年（1506年）に長尾能景が越中で戦死し跡を長尾為景が継ぐと両者の対立は表面化し、越後永正の乱では八条尾張守・龍松父子や上杉成定が自害に追い込まれるなどして大きな打撃を受けた。