 The exact location of the Sino-Russian border along the left bank of the Tumen River was an area of contention (the entirety of the right bank of the river belonging to North Korea).The Convention of Peking (Beijing) set the location of border at 24 km (15 mi) above the mouth of the river, where it enters the Sea of Japan, but through Chinese negotiation was later moved to about 15 or 16 km (9 mi) above the mouth.In 1964, both sides agreed to a border about 17 km (11 mi) above the mouth, and these terms were kept in the 1991 agreement.