Japanese monetary policy has spent most of this century as a study in immobility. That has ended. In June 2026 the Bank of Japan raised its policy rate to 1 per cent, the highest level in more than thirty years, then held at that level at its July meeting. Neither move stopped the yen from weakening. By late July the currency was trading near 164 to the dollar, a level last seen in the mid-1980s.

Intervention that did not hold

The Ministry of Finance did not stand aside. Between late April and late May 2026 it spent roughly ¥11.7 trillion, around US$72 billion, buying yen. The effect proved temporary. Currency intervention works best when it reinforces an interest rate differential rather than fighting one, and the gap between Japanese and American yields, though narrowing, remains wide enough to keep capital flowing out.

That has produced an unusual political alignment. Reports in mid-August indicated that Prime Minister Sanae Takaichi’s government now supports a faster tightening path, with the next increase expected in September or October. Governments do not normally lobby for higher rates. This one appears to have concluded that a disorderly currency is the greater risk.

The affordability trap

Takaichi’s Liberal Democratic Party won a landslide in February 2026 partly on an affordability platform, including consumption tax reductions on food. A weak yen undercuts that promise directly, because Japan imports most of its energy and a large share of its food. At the same time, the Prime Minister has tempered expectations for large fiscal stimulus in order to reassure a bond market already digesting ten-year yields near 2.9 per cent, the highest since 1996.

The result is a narrow policy corridor: tighten enough to defend the currency and contain imported inflation, but not so fast as to destabilise a debt stock that remains among the world’s largest relative to output.

The regional read-across

For businesses across Asia the yen’s level is not a spectator sport. Japanese exporters gain price advantage against Korean, Taiwanese and Chinese competitors in third markets. Japanese firms shopping for overseas acquisitions find every target more expensive in home-currency terms, which has historically slowed outbound deal flow. Regional suppliers invoicing in yen are absorbing a real-terms cut.

The funding channel matters too. Cheap yen has underwritten carry trades across emerging Asia for years. As Japanese yields rise, some of that funding unwinds, and the effects show up in unrelated markets, as investors were reminded during previous episodes of sudden yen strengthening.

Summary

The Bank of Japan has lifted rates to 1 per cent, the highest since 1995, yet the yen has fallen to a forty-year low near 164 to the dollar despite ¥11.7 trillion of intervention. The Takaichi government now favours faster tightening, with a move expected in September or October. Anyone with Japanese suppliers, customers, acquisitions or yen-denominated funding should treat the next two BOJ meetings as material events, and should stress-test both a continued slide and a sharp reversal.