TOKYO — For Japan, the ramping up of sanctions by the West against Russia can be summed up in a familiar phrase: It's complicated.The tug-of-war over Ukraine threatens to derail Japanese Prime Minister Shinzo Abe's moves toward rapprochement with Russia. Relations between Japan and Russia have suffered for decades due to a territorial dispute that has prevented the signing of a peace treaty after World War II.Yet Japan must toe the line on sanctions: It cannot spurn its main ally the U.S., nor European partners. It also has good reason to stand strong against Russia's apparent support for pro-Russian insurgents who have destabilized swaths of eastern Ukraine, given the parallels with China's ambitions toward disputed Japanese-controlled islands in the East China Sea.Japan's chief government spokesman offered only vague support Thursday for the coordinated American and European moves targeting Russian energy firms, financial institutions, arms suppliers and four individuals."We are watching the situation of the EU and U.S.," Chief Cabinet Secretary Yoshihide Suga said at a regular briefing. "Working with the international community is our stance regarding Ukraine, so we would like to take appropriate measures in line with that attitude."His terse reply says plenty about Japan's ambivalence over the issue.---LIMITED SANCTIONSJapan has imposed sanctions on Russia, but in a very limited way. It has suspended bilateral talks on some issues, and imposed an entry visa ban on 23 individuals, whom it hasn't publicly named."Japan is really signaling to Russia that it's not fully committed to the sanctions. It's going along but wants to keep a balanced position," said James D. J. Brown, a political science professor at Temple University's Japan campus in Tokyo.The visa ban apparently doesn't apply to Sergey Naryshkin, who as chairman of the lower house of Russia's parliament was sanctioned by the U.S. and EU after Russia annexed Crimea. He visited Japan last month to inaugurate a cultural festival, where he delivered a message from Putin praising the event as a way of "enhancing our mutual trust."Naryshkin also dined with former Japanese Prime Minister Yoshiro Mori, who had been shuttling between Tokyo and Moscow as an unofficial envoy, having declared resolution of the territorial dispute his "lifelong duty."A visit by Russian President Vladimir Putin to Japan planned for the fall appears to be still in the works.---THE ENERGY AND CHINA FACTORSTokyo is wary about Beijing cozying up to Moscow, said Valerie Niquet, a senior research fellow at the Foundation for Strategic Research in Paris."Tokyo remains interested in rapprochement with Russia to balance Beijing," she said.Energy is one vital bond. Japanese and Russian companies are pushing ahead with projects, including a liquefied natural gas facility in Sakhalin to increase shipments to Japan and other Asian countries."The Russians are not open at all to accepting a lot of investments from China including in energy, so they've built a strong working relationship with Japan," Niquet said.Putin has also obliged Abe by remaining neutral on the islands in the East China Sea that are claimed by both Tokyo and Beijing.---TERRITORIAL CONUNDRUMDespite those shared interests, it is unclear if Japan and Russia can bridge their dispute over four islands just off the northern tip of Hokkaido.The Russians captured the islands at the end of World War II, but they are claimed by Japan and a pet cause of Japanese nationalists.Brown noted that, given Russia's insistence on protecting Russian speakers in Crimea, it seems unlikely that Moscow would give up sovereignty over islands populated mostly by Russian speakers.