However as the unification of Tosa by Motochika CHOSOKABE became increasingly realistic, the local clans who were in the area east of the Shimanto-gawa River turned to Motochika for alliance, and as such, the area where the Ichijo clan could exert their influence was contained within the areas downstream and west of the Shimanto-gawa River.
しかし長宗我部元親による土佐統一が現実味を帯びてくると、四万十川以東の豪族が次々と元親に下り、一条氏の影響地域は四万十川下流域と以西に押し込められてしまった。