The Russians are currently building a 136 mile (219 km) pipeline across the Tatar Strait from Sakhalin Island to De-Kastri on the Russian mainland.
A well placed small Semtex charge or a submarine with a drag line, in the beginning of winter would paralyze the oil production for 6 months.
Meanwhile we should support the Japanese claim to the Kuril and Sakhalin islands and condemn the Russians for the Genocide of the Japanese in the 19th century.
How about condeming Russia, Belarus and Kazakhstan for the crimes of the Soviet Union until they fess up.