Credit Agricole CIB Research discusses the scope of JPY intervention.

"Today, USDJPY was again testing the important 158 technical level, although the exchange rate’s advance was not halted by suspected intervention, but instead by BoJ dove Kazuyuki Masu signalling he could be willing to support a June rate hike...We get Japan Q1 GDP data next week and Masu’s rhetoric has potentially upped the ante on this data release as well as other cyclical data releases in the coming weeks ahead of the BoJ’s June meeting," CACIB notes.

"But strong support for the JPY is unlikely for several reasons in our view: (1) Japan’s rates market is already nearly 75% priced for a June rate hike; (2) if the BoJ does hike rates, a follow up rate hike will likely be another six months away; and (3) when it comes to relative US-Japan rates, the US side of the ledger is the stronger driver of USD/JPY and a hawkish shift at the Fed backed by strong US inflation data are driving US rates higher. So further intervention is likely the only way to cap USD/JPY for now," CACIB adds.