JP Morgan Research discusses the scope of further JPY intervention by Japan's MoF.

"It is clear from recent developments that Japan’s currency  authorities view USD/JPY 160 as a line in the sand. Whether  additional intervention occurs will depend on how the market  evolves, but estimated intervention to date totals around JPY  9 trillion—below the JPY 15 trillion seen in 2024—suggest ing there is still room to intervene. As such, if USD/JPY rises to around 159–160 again, the likelihood of additional  intervention is high," JPM notes.

"The 160 level is, if anything, a politically determined  threshold. In June and July 2024, after USD/JPY had moved  into the 162 area, prominent LDP politicians commented that  the BOJ should raise rates to curb excessive yen weakness,  and the BOJ surprised the market by hiking. The BOJ’s rate  hike last December following the formation of the Takaichi  administration can be interpreted in a similar context. In  Japan, the MoF is responsible for FX policy, which makes the  latter more susceptible to a political overlay," JPM adds.