Bolshoy Ussuriysky Island , or Heixiazi Island , is a sedimentary island at the confluence of the and Amur rivers, along the border between the People's Republic of China and Russia. Its area is about 327 to 350 km?. It is bounded closely by Yinlong Island, or Tarabarov Island, and over ninety islets . Its position at the confluence of the Amur and the Ussuri and right next to the major Russian city of Khabarovsk, has given it great strategic importance.
Until 2004, Bolshoy Ussuriyskiy Island was the site of a territorial dispute between China and Russia. The Soviet Union occupied Bolshoy Ussuriyskiy and Yinlong Islands in 1929, but this had not been accepted by China. While Russia governed the islands as a part of Khabarovsk Krai, China claimed them as a part of Fuyuan County, Heilongjiang province, and the easternmost part of China.
On October 14, 2004, the Complementary Agreement between the People's Republic of China and the Russian Federation on the Eastern Section of the China-Russia Boundary was signed, in which Russia agreed to relinquish control over Yinlong Island and around half of Bolshoy Ussuriysky. In return, China agreed to drop all territorial claims to the remainder of Bolshoy Ussuriysky kept by Russia. In 2005, the Russian Duma and the Chinese National People's Congress approved the agreement. On July 21, 2008, an agreement was signed in Beijing by the Chinese and Russian Foreign Ministers, that finalized the border demarcation and formally ended negotiations. Under the agreement, Russia will transfer approximately 174 km? of territory to China. The area being transferred to China is largely uninhabited.
The agreement has not met complete approval on either side of the border. In May 2005, Cossacks in Khabarovsk demonstrated against the loss of half of Bolshoy Ussuriysky. In return, some Chinese commentators, especially the media in Hong Kong, Taiwan and overseas which are outside the control of PRC government censorship, criticized the PRC government for signing the agreement, which they regarded as sealing as permanent the loss of former Chinese territory, such as Outer Manchuria, to Russia.
The government of the Republic of China has never recognized border treaties signed by the PRC or any other countries. Therefore Taiwan still formally claims all parts of the Heixiazi Islands.