Japan is making a sweeping shift in its monetary policy, aiming to spur inflation and get the world's third-largest economy out of a long, debilitating slump. Bowing to demands from Prime Minister Shinzo Abe for more aggressive monetary easing, the Bank of Japan announced Thursday a policy overhaul intended to double the money supply and achieve a 2 percent inflation target at the "earliest possible time, with a time horizon of about two years."