The Bank of Japan shifted the focus of its monetary stimulusWednesday from expanding the money supply to controlling interestrates, which some economists deemed as further evidence that BOJpolicy had reached the limits of its effectiveness.

The centralbank said it would adjust the volume of its assetpurchases, the core of its framework until now, as necessary in theshort term to control bond yields, while keeping it at about 80trillion yen ($780 billion) annually over the long term. The BOJalso scrapped a target for the average maturity of its holdings ofgovernment bonds.

The changes will help the BOJ manage the impact of its purchasesand negative interest rates on Japanese banks, whose profits havebeen squeezed by a narrowing of short-term and long-term yields.Governor Haruhiko Kuroda and the policy board kept that negativerate, imposed on a share of bank reserves, unchanged at minus0.1%.