Japan has already spent more than US$200 billion since 2022 selling dollars to support the yen.
The most recent intervention was US$54.7 billion.
The problem is that the custody curve at the Fed continues to fall, meaning that interventions are slowing the fall but not reversing the structural trend.
As long as the interest rate differential between the US and Japan remains, the selling pressure on the yen will not disappear.
The Bank of Japan is in a dilemma: raising interest rates to defend the currency implies pressure on a public debt of 260% of GDP.
Currency intervention buys time. It doesn't solve the problem.
In such situations, those in power never intend to solve the problem; they simply spend and spend. And the problem falls on others (usually the general public)