Remaining wave headland, which means port, used to be the port where the Ryukyu Kingdom paid tribute to the Heavenly Dynasty and went out to sea. The sea was very windy, so there were residual waves. Every year when the monsoon comes, the ships go to sea and reach Fujian by the wind south. Then the envoys go all the way north along the dry road. Along the way, they also use tributes to exchange for what they need. When the monsoon changes its direction, it will return to Tianjin.