On the other end of the spectrum, though the port of Tonkin in northern Vietnam played an important role in the region's silk trade, the local Trinh authorities actively discouraged the formation of a "Nihonmachi" there. This is believed to have largely been the result of concerns over the martial nature of the Japanese in the region (many were samurai serving as pirates and mercenaries), and over the shipments of weapons and munitions from Japan to Siam and southern Vietnam. In order to avoid potential violence within their chief port, the Trịnh Lords sought to avoid any significant permanent Japanese presence, though many notable and prominent Japanese merchants did frequently make port there.