Exclusive-Japan top FX diplomat urges markets to heed 'very clear' warning on yen

TOKYO, Sept 28 - Japan's top currency diplomat, Atsushi Mimura, urged markets on Monday to heed the "very clear" warning delivered by Tokyo and Washington regarding the yen. Mimura, who is seen as a strong advocate for acting against excessive falls in the currency, expressed his resolve to take action. US President Donald Trump raised concerns about yen weakness during a summit with Japanese Prime Minister Sanae Takaichi.

Finance Minister Satsuki Katayama provided an unusually detailed account of the leaders' discussions on currencies, stating that Japan's prime minister, finance minister, and the US had sent a very clear message, and markets should take it at face value. Mimura stated that he would closely monitor whether markets continue to take the message seriously.

While he did not comment on potential future intervention by Japan, Mimura remained unsatisfied and unreassured about the yen's recent moves, indicating that Tokyo remains vigilant against the risk of renewed declines in the currency. The shared determination of Tokyo and Washington to address the weak yen was evident as Katayama and her US counterpart Scott Bessent reaffirmed in phone talks on Friday that the yen's undervaluation is a matter of concern.