Japan is an oil importer. Japan's currency is the Japanese yen (JPY), but oil is priced in USD per barrel. If the Federal Reserve lowers interest rates in the United States and there is no change in either the USD price of oil or the JPY/USD spot rate, what should the Bank of Japan do to interest rates in Japan (raise, lower, leave unchanged) so that the cost of oil in JPY does not increase in the future? Assume that the action of the Bank of Japan has no impact on the JPY/USD spot rate or subsequent Fed rate changes. Support your policy recommendation with the appropriate equation(s).