With its reluctance to add to record monetary stimulus even as inflation remains well below its target, the Bank of Japan has stoked speculation about it scaling back its asset purchases as soon as early 2016.

Economists in recent weeks have been re-examining the BOJ's stated goal of keeping its "quantitative and qualitative" easing program as long as needed to maintain stable 2 percent inflation. Barclays PLC analysts highlight that the pledge doesn't specify continuing with the current pace of asset purchases.

Few analysts see consumer prices rising at a sustained 2 percent pace starting next year — that's a rate that Japan hasn't consistently maintained since the early 1990s. Yet Morgan Stanley MUFG Securities Co. is among those who now predict the BOJ will cut back on stimulus in 2016, with Nomura Holdings Inc. and Credit Suisse Group AG seeing it in the first half of the year.