Evidence of China's sea boundary in the South China Sea

According to a series of important historical maps, i.e., the Location Map of the South China Sea Islands, the Nansha Islands, Zhongsha Islands, Xisha Islands, Yongxing Island and Shidao Island, and Taiping Island (archived by the Territorial Administration Division of the Ministry of Interior of Republic of China in 1946), and the Administration District Map of the Republic of China published in 1948, the dashed line surrounding the South China Sea Islands represents China's sea boundary in the South China Sea at that time. It was both connected with, and an extension of, the land boundary of China. At that time the dashed line was used to represent the waters boundaries while the solid line was used to represent the land boundary-a universal method used in maps that was then recognized internationally. The above observation provides historical and scientific evidence of China's sea boundary in the South China Sea that is useful for the international maritime delimitation over the South China Sea area.