Japanese policymakers are turning their attention to more structural economic factors behind persistent yen declines, convinced that market intervention is limited in its ability to reverse the currency's broader slide.

Data due out on Friday is likely to show Japan spent roughly ¥9 trillion ($57.2 billion) late April through early May to slow the decline in the yen, which hit a 34-year low below ¥160 to the dollar.

While the wide U.S.-Japan interest rate gap is typically blamed for the yen's declines, the currency's persistent weakness has alerted policymakers to other more fundamental drivers, such as Japan's dwindling global competitiveness.