Economists at OCBC Bank discuss policymakers’ readiness to act on JPY’s weakness.

If USD/JPY trades volatile by another 2-3 JPY intra-day, then authorities could really act

If USD/JPY trades volatile by another 2-3 JPY intra-day, then authorities could really act. That said, such activities (jawboning, etc.) probably only serve to slow the pace of USD/JPY upticks especially if the uptrend remains intact. 

A reversal in the trend would require market dynamics to change (i.e. USD to turn or yield differentials to narrow, etc.).