Yen Jumps on Warning from Japan's Top Currency Diplomat

The yen jumped after Japan's top currency diplomat Atsushi Mimura issued another warning about the country's currency weakness. The dollar fell below 157 and the yen briefly strengthened to around 156.75, its strongest level since September 18.

Mimura said that Tokyo and Washington had sent a 'very clear' message, and markets should take it at face value. He added that he was 'neither satisfied nor reassured' by recent yen moves and would be watching closely if the market continues to take the warning seriously.

The reaction shows how sensitive foreign exchange markets are to Tokyo's language. The yen erased earlier losses, suggesting that policymakers are willing to escalate if depreciation continues.

Mimura's comments followed a disclosure from Finance Minister Satsuki Katayama that US President Donald Trump had raised yen weakness concerns during a summit with Prime Minister Sanae Takaichi. Reuters reported that Katayama and US Treasury Secretary Scott Bessent reaffirmed in Friday phone talks that yen undervaluation is a concern.