Japanese authorities on Monday intensified their warnings over renewed yen weakness, saying they were prepared to take “appropriate” action against excessive and speculative foreign exchange moves, a stance that has once again put market intervention firmly in focus.
Atsushi Mimura, Japan’s top currency diplomat, said recent movements in the yen had been “one-sided and sharp,” language that Japanese officials have historically used ahead of direct intervention.
“The recent foreign exchange moves were one-sided and sharp, and I’m concerned about them,” Mimura told reporters. “We’ll take appropriate actions against excessive moves.”
Chief Cabinet Secretary Minoru Kihara reinforced that message, stressing that currency markets should move in a stable way that reflects economic fundamentals.
“The government will take appropriate measures against excessive movements, including speculative ones,” Kihara said, adding that authorities were watching developments closely.
The renewed warnings come as Japan continues to struggle to stabilize its economy after years of volatility that have weighed heavily on the yen. The country has faced a difficult mix of weak domestic demand, rising import costs, stubbornly low productivity growth, and repeated external shocks, leaving policymakers with limited room to maneuver. These pressures have made the currency particularly sensitive to global interest-rate shifts and investor sentiment.
Although the Bank of Japan last week raised its policy rate to 0.75% from 0.5%, taking borrowing costs to their highest level in roughly three decades, the move did little to support the yen. Instead, the dollar rose to as high as 157.67 yen on Friday, its strongest level in four weeks, as markets focused on Governor Kazuo Ueda’s cautious tone and the lack of clear guidance on when the next rate increase might come.
That reaction underscored a central challenge for Japan. While the BOJ has begun a slow exit from ultra-loose monetary policy, interest rates remain far below those in the United States, where the Federal Reserve has kept borrowing costs elevated. The resulting rate differential continues to encourage capital outflows and put downward pressure on the yen.
The currency’s weakness carries real economic and political consequences for the government. A softer yen pushes up the cost of imports such as energy, food, and industrial raw materials, squeezing households already grappling with higher living expenses. While exporters benefit from a weaker currency, officials have repeatedly warned that sharp or disorderly moves risk undermining economic stability and public confidence.
Kihara said the government would “closely monitor the impact of higher interest rates while cooperating with the Bank of Japan,” highlighting the need to balance currency stability with the risk that tighter policy could further slow growth. Japan’s recovery has been uneven, and officials remain wary of tightening financial conditions too aggressively at a time when consumption and investment are still fragile.
Bond markets reflected the tension on Monday. Japanese government bonds weakened further following last week’s rate hike, with the two-year yield, the most sensitive to monetary policy, climbing to a record high, and the 10-year yield hitting its highest level in 26 years. Rising yields suggest investors are reassessing Japan’s long-standing low-rate environment, even as uncertainty remains over the pace of future policy tightening.
Japan has intervened directly in currency markets in the past when yen declines became too rapid, most notably in 2022. While officials typically stop short of confirming any immediate plans, repeated references to “excessive” and “speculative” moves are widely interpreted by markets as a warning signal.
With the yen again under pressure, global rates still high, and Japan’s economic recovery fragile, investors are watching closely to see whether the government’s verbal warnings will translate into concrete action to stem further currency volatility.






