There appears to have been a series of complicated circumstances underlying this dispute; such as Kenshin's sudden death before the completion of arrangements for the succession, as well as struggles for power which continued for generations mainly among the Nagao families in Echigo.
これは謙信が後継体制を整えないうちに急死してしまったことや、越後の長尾諸家を中心とした、何代にも渡る権力争いなどの複雑な事情が背後に絡んでいるとされる。