When the confrontation between the Hosokawa clan and Ouchi clan became serious, the Hosokawa clan avoided taking the Seto Inland Sea route that passed near Yamaguchi, the base of the Ouchi clan, and instead took the route to sail for Neiha via Urado and Shimoda in Tosa Province and Aburatsu and Bonotsu in southern Kyushu.
細川氏と大内氏の対立が深まると、細川氏は大内氏の山口の側を通る瀬戸内航路を避け、土佐の浦戸、下田、南九州の油津、坊津を経由して寧波に行く航路をとった。