The Ouchi clan and Shoni clan were old enemies with each other who fought over hegemony of Kitakyushu (Dazai-fu (local government office in Kyushu region)) all through the Muromachi period.
大内氏と少弐氏とは、室町時代を通じて北九州（大宰府）の覇権を争う宿敵同士であった。