In the wake of Tokyo's solo intervention to weaken the yen, the Bank of Japan eased monetary policy by boosting its asset buying scheme today.
The central bank maintained its benchmark policy rate at a range of zero to 0.1 percent.
The BOJ increased its 10 trillion yen, or 130 billion US dollar, asset buying programme by 5 trillion. It also increased the 30 trillion yen program offering cheap fixed-rate funds via market operations by 10 trillion yen.
The size of the asset buying pool is the main gauge of the BOJ's policy since it pledged in October 2010 to keep its rate virtually at zero until the end of deflation was in sight.
Inflation has plagued the Japanese economy for a decade.