TOKYO—Japan does not know how Russia will handle the required rouble payments for its energy sold to “unfriendly” countries, the finance minister said on Thursday. Japan accounted for 4.1 percent of Russia’s crude oil exports and 7.2 percent of its natural gas exports in 2021. “Currently, we’re looking into the situation with relevant ministries as we don’t quite understand what is (Russia’s) intention and how they would do this,” Finance Minister Shunichi Suzuki said in a parliament session. The government will also coordinate with Japanese companies to collect information about the move, Chief Cabinet Secretary Hirokazu Matsuno told a Thursday news conference. Russia’s President Vladimir Putin said on Wednesday his country would seek payment in roubles for gas sales to “unfriendly” countries in retaliation for Western sanctions against its invasion of Ukraine. Russia has put Japan on its “unfriendly” nation list along with the United States, European Union member states, …