Bank of America Global Research discusses the scope for another round of JPY intervention by Japan's MoF.

"The rule of thumb that ¥1 trillion of intervention moves USD/JPY by roughly one yen appears broadly consistent with the April-May intervention episode  

For example, if intervention were to begin with USD/JPY in the 163s, pushing the exchange rate below 155-and thereby exceeding market expectations-could require intervention on the order of ¥10 trillion in a single day, or more than ¥15 trillion across multiple operations," BofA notes

"The hurdle for a Bank of Japan rate hike at the July meeting appears high, while the following policy meeting is not until mid-September. Against that backdrop, the possibility of more aggressive intervention cannot be ruled out," BofA adds.