The northeast Asian equation, with its complex matrix of rising economic power in South Korea, an erratic and unpredictable North Korea, a Japan beset by uncertainty and lingering calamity - and the undisputed titan, China - remains incomplete without understanding the one card in the deck that is all too often overlooked: Russia.
With its growing global role as a major energy exporter, Sakhalin Island, in Russia's Far East region, has become one of its most valuable but least recognised geographic assets - and a prime example of why Russia is an increasingly dominant player in Far East Asian politics and resource exploitation.
Sakhalin: Russia's East Asia trump card - Opinion - Al Jazeera English