For the first time, Bank of Japan Gov. Haruhiko Kuroda said his original two-year time frame for reaching 2 percent inflation will not be reached. But it did not prompt him to step on the stimulus accelerator.

That combination escalated the risk of the central bank being perceived as the type of reactive — and ineffective — institution reflationists say that it was under Kuroda's predecessor. In a press conference after Thursday's board meeting, Kuroda went on the defensive, repeatedly saying no easing was needed now and that there was no need for trust in the BOJ to fall.

"There's a danger that the BOJ will become reactive, rather than proactive, if the central bank keeps a wait-and-see stance for too long," said Yuichi Kodama, an economist at Meiji Yasuda Life Insurance Co. in Tokyo.