Sakhalin Island was originally named Kuye, Kuwu, Gu Wei or Heilongyu in China, translated as Sakhalin Island in Russia, and called "Xiayidi in the North" or "Huatai" in Japan.
Sakhalin Island is located in the northeast of Eurasia, southeast of the estuary of Heilongjiang, facing the Sea of Okhotsk in the east, facing the mainland through Miyako Strait in the west, and adjacent to Hokkaido in Japan across Zonggu Strait in the south. It is the largest island in the Russian Federation, under the jurisdiction of Sakhalin State, with an area of about 76400km? .
The northern part of Sakhalin Island is relatively flat, dominated by hills and mountains, and the southern part is composed of East Sakhalin Mountain Range and West Sakhalin Mountain Range, with the highest peak of1420m. The island is rich in forest resources, with coniferous forests in the north, mineral resources such as oil, coal and gold underground, and aquatic resources in coastal areas, which is one of the main producing areas of salmon. The earliest inhabitants of the island are Chiriac, Ewenki and Ainu.
Sakhalin Island was ruled directly or indirectly by China dynasties in history. 1On September 7th, 689, China and Russia signed the Treaty of Nebuchadnezzar Chu, which determined that the vast areas of Heilongjiang and Ussuri River basins, including Sakhalin Island, belonged to Russian territory.