In the late 16th century through the beginning of the 17th, a large chain was at times extended across the harbor, between the two fortresses, to block pirates or other ships from entering the harbor. By [[1609]], cannon were mounted at each of the two fortresses as well.<ref>Turnbull, Stephen. ''The Samurai Capture a King: Okinawa 1609''. Oxford: Osprey Press, 2009. p26-27.</ref> | In the late 16th century through the beginning of the 17th, a large chain was at times extended across the harbor, between the two fortresses, to block pirates or other ships from entering the harbor. By [[1609]], cannon were mounted at each of the two fortresses as well.<ref>Turnbull, Stephen. ''The Samurai Capture a King: Okinawa 1609''. Oxford: Osprey Press, 2009. p26-27.</ref> |