During the Kamakura era
and the Muromachi era (1192 -
1575), groups of marine guards
appeared and came to dominate the vital supply routes in
Inland Sea between the western
province and Kyoto, then the
capital of Japan.
The ancient manuscripts tells of the
activities of Kutsuna
Family who led the Kutsuna Suigun. They were the one of the Iyo Suiguns.
They had the privilege of knowing the navigation of ships
and they taxed all the traders and Samurai worriers who
tried to go through the channels.