The root cause of the South China Sea dispute is China’s nine-dash line that appears in the 1947 map invented by the Kuomintang Party, which controlled the Chinese government at that time. The 1947 map is titled “Location Map of South Sea Islands,” clearly signifying a claim to islands and their territorial seas, and not a claim to the waters and resources within the nine-dash line beyond the territorial seas. The nine-dash line encloses about 85.7 percent of the South China Sea. At that time, international law recognized a territorial sea of only three nautical miles. Beyond the territorial sea were the high seas which belonged to all mankind.

Carpio, A. T. (2020, July 30). Inventor of China's nine-dash line. Philippine Daily Inquirer, p. A6.