evidence: The Yalu and Tumen Rivers, and control of the seas 15Since 1949, China and North Korea have accepted that the course of the Yalu and Tumen rivers constitute the border between the two countries. However, they have refused to situate the demarcation line in the middle of the rivers, adopting the principle of joint ownership, management and use of the two waterways. [...] 18Another polemic of significance concerns the island of Shindo (Shin in Chinese), situated in the estuary of the Yalu River. In spite of Chinese claims, Shindo has for a long time belonged to Korea, and under Japanese occupation was a production centre for raw materials for textiles, as the place is covered in reeds. The Chinese authorities regard the island as a station of major importance for transport and communication in the development of oil extraction in the Gulf of Beihai. For Pyongyang, ownership of the island favours its strategic position at the mouth of a river that serves as a boundary-mark between the two countries14.