The Bank of Japan is poised, for the third time in less than a year, to push back the time frame for reaching its inflation target, making it harder for policymakers to hold off from enlarging monetary stimulus.

Gov. Haruhiko Kuroda until now has been resisting further expansion of the asset-purchase program since 2014, arguing that the repeated reductions in consumer price forecasts largely resulted from falling oil costs, which are outside of the BOJ's influence.

The difficulty for board members at their Jan. 28 to 29 gathering is that they confront a confluence of other challenges: diminished inflation expectations among companies and investors, subdued wage increases, a sell-off in stocks and strengthening in the yen. The question is whether more monetary stimulus, on top of what's already an initiative of record scale, could help change the dynamic.