At the G20 Hangzhou summit earlier this month, China made clear that Russian president Vladimir Putin was a top guest. Both China and Russia claim that their bilateral relations are the “best ever’ and demonstrate an “unprecedentedly high level of trust.” Putin described the relationships as a “comprehensive partnership and strategic collaboration.”

The China–Russia relationship is based on a mutual wish to push back against the United States, for its expansion of NATO in Europe and its rebalance in the Asia–Pacific. Sanctions imposed on Russia by the US and Europe have hurt the Russian economy, and Russia needs markets for its energy exports, especially gas. China has signed a major deal to import Russian gas and it is a large market for Russian manufactured weapons and technology.

However, Russian and Chinese interests always aren’t congruent. Russia is suspicious of Xi Jinping’s ‘One Belt, One Road’, which aims to expand into Central Asia. Moscow also faces the difficult challenge of improving relations with China while at the same time not undermining its traditional ties with India and Vietnam, which both feel pressure from Beijing.

http://nationalinterest.org/blog/the-buzz/does-russia-have-south-china-sea-problem-17853