“The BOJ is now essentially data-dependent, which is a big change in the BOJ reaction function and opens up the scope for greater FX volatility that should discourage a further build-up of yen carry positions at these weaker yen levels. Import inflation is again picking up, and government subsidies that are helping to depress inflation will end on April 30,” Derek Halpenny, head of research, global markets at MUFG Bank, said in a note sent to clients after the rate hike.