After twice this year putting off his inflation target yet declining to step up monetary stimulus, Bank of Japan Gov. Haruhiko Kuroda has discouraged some analysts from thinking he'll ever boost policy again.

Forty-four percent of economists surveyed by Bloomberg had expected a move by Kuroda at the meeting last Friday, with a further 22 percent projecting action sometime between December and April. With policy unchanged even as the central bank cut forecasts for growth and prices, some observers are now struggling to determine what it would take for the governor to pull the trigger for more asset purchases.

"The possibility of further easing is highly unpredictable," said Kyohei Morita, the chief Japan economist for Barclays Plc. "The BOJ has become something I don't really understand," said Morita, who's been analyzing the Japanese economy for more than two decades.