In the early modern era, Otsu was opposed to other ports such as Matsubara and Maibara City; but during the Edo period Matsubara, Maibara and Nagahama City as `Hikone-han-san-minato' (three ports in Hikone-han) were protected by the Ii clan.
近世になると、大津は松原や米原市など他の港と対立し、江戸時代には松原、米原、長浜市が「彦根藩三湊」として井伊氏の保護を受けた。