evidence: Chinese soldiers raise a national flag during a ceremony on the Heixiazi Island Oct. 14, 2008. China and Russia held a ceremony on the Heixiazi Island Tuesday to unveil the boundary markers for the eastern section of their border. [Xinhua] [...] Related readings: China-Russia boundary marker unveiled China to regain control half of Heixiazi island [...] The 300-sq-km Heixiazi Island is located at the confluence of the Heilongjiang and Wusulijiang rivers that serve as a natural border between China and Russia. It was occupied by the former Soviet Union during a 1929 border skirmish.