U.S. Treasury Secretary Bessent explained this in interviews with CNBC and the Nikkei. In his interview with the Nikkei, he stated the following.
When asked about the reasons for intervening to buy the yen, Mr. Bessent replied, “Many Asian currencies are linked to the yen. The Asian currency crisis of the 1990s was triggered by a sharp depreciation of the yen.”
This reflects concerns that mounting pressure to sell the yen could spill over into Asian currencies.

In the late 1990s, the Japanese yen fell by as much as 30 yen against the dollar in a single year, contributing to the worsening of the Asian currency crisis in countries such as Thailand and Malaysia.
Regarding current Asian currencies, Mr. Bessent pointed out, “Because the yen is weak, the South Korean won is also weak, and China has become reluctant to revalue the yuan.”

The latter part of this statement—“China is also becoming reluctant to revalue the yuan”—is likely significant.
In other words, there is talk of revaluing the Chinese yuan.

The Mar-a-Lago Agreement—or “Plaza Accord 2.0”—is alive and well.
Treasury Secretary Bessent holds the conviction that the Bretton Woods system should be rebuilt, and this has now taken concrete form.

To prevent a fire sale of U.S. assets, the dollar will be devalued on a large scale.
That grand plan has likely already begun.

Looking back at past coordinated interventions, there have been many cases where they coincided with major market tops and bottoms.
In that sense, this coordinated intervention could mark a major market peak in the long run.
However, looking at the prevailing sentiment, most analysts believe that as long as the Takaichi administration’s expansionary economic policies continue, the trend toward a weaker yen will eventually resume.

It is true that as long as the Takaichi administration’s policies remain unchanged, the trend toward a weaker yen will persist—but ultimately, they will likely have to align with Mr. Bessent’s intentions.

Finance Vice Minister Mimura has stated, “We intend to continue responding in close coordination with the Bank of Japan’s monetary policy.”
What does “coordination with the Bank of Japan’s policy” mean?
Presumably, behind the scenes of this coordinated intervention, the Bank of Japan is being urged to tighten policy sooner rather than later.

If that is the case, an interest rate hike in September is a possibility.
At the very least, a shift toward a more hawkish monetary policy has begun.