At the beginning of the Jinshin War, Oama no Miko left Yoshinonomiya Palace (present Nara Prefecture), then in the Imperial Court of Yamato City of Yamato Province (present Nara Prefecture) Otomo no Oji (Prince Otomo who was the enemy of Oama no Miko in the war) formed an army to suppress Oama no Miko and the followers.
壬申の年の勃発時、吉野宮から大海人皇子（天武天皇）が去ってから、倭（大和国）では大友皇子の朝廷のもとで軍の編成が進められた。