Vietnam has signed the contract to purchase six Kilo class submarines, for $300 million each, from Russia. This is part of a larger package, that includes over a dozen patrol boats, at least two frigates and dozens of aircraft. In effect, Russia is supplying the weapons to modernize Vietnam's armed forces. Until Vietnam enacted market economy reforms in the last two decades, the country was broke. But that has changed, and Russia offered attractive prices. This annoys China, which considers Vietnam part of southern China. But despite centuries of military efforts, the Chinese could never keep Vietnam under control. Now Russia is arming this wayward part of the motherland. China has not made open claims on Vietnam for over a century, but the animosity, and memories, are still there.
With Russia weak on their China front, they have an interest in getting the Chinese to look over their shoulder in the far south as much as possible. India already provides a distraction, as do South Korea, Japan, Taiwan, and America. With China building up a major naval base on Hainan Island, having Vietnamese naval forces capable of prowling around there will not make China happy. Heck, India might want to look into helping Vietnam out.
Really, the Russians might want to look into supplying Taiwan with some modern submarines for a really effective distraction for China.
