Having Bungo as the base, the Otomo clan increased its power in Chikugo where Chikugo jugojo (literally, fifteen castles in Chikugo) represented by the Kamachi clan in South Chikugo exists and Higo where the Aso clan and the Sagara clan existed.
大友氏は豊後を拠点に南筑後の蒲池氏を筆頭とする筑後十五城が盤踞する筑後、さらに阿蘇氏や相良氏の肥後に勢力を伸ばした。