Outside the Four Seas / Overseas
Outside the Four Seas refers to the territory outside China, foreign lands, or remote areas. The ancient Chinese thought that China’s territory was surrounded by the Four Seas (the East, West, North, and South seas). Therefore, places outside China were outside the Four Seas. It reflected the ancient Chinese belief that the seas were the natural boundary of a country. It also suggested that the ancient Chinese were on the one hand self-focused and on the other open-minded, longing to explore the unknown world outside the Four Seas.
Xiangtu was so brave that he was recognized and extolled even by those outside the Four Seas. (The Book of Songs)