Foreign residents in Japan are facing renewed currency volatility as the yen weakened to 157 per dollar on November 21, 2025, prompting strong warnings from Japanese financial authorities about potential market intervention. The development marks a significant shift in Japan's currency landscape, with direct implications for expats' purchasing power and financial planning. According to NHK, the Tokyo foreign exchange market saw the yen trading at the 157-per-dollar level throughout most of November 21, representing a continuation of the weakening trend that has concerned policymakers. However, the afternoon session brought some relief as traders began buying back yen they had previously sold, suggesting market participants are taking government warnings seriously. Finance Minister Katayama issued a stern warning about the currency movements, describing them as "extremely one-sided and rapid," according to NHK reports. Critically, he stated that government market intervention "should naturally be considered," signaling that authorities are prepared to take action to stabilize the currency. This marks a significant escalation in official rhetoric and suggests that tolerance for further yen weakness may be limited. For expats living in Japan, a weaker yen has mixed implications. Those earning income in yen but maintaining financial obligations abroad—such as student loan payments, mortgages, or family support in their home countries—face increased costs as their yen-denominated salaries purchase fewer foreign currency units. Conversely, foreign residents receiving income from overseas in dollars, euros, or other major currencies will find their purchasing power in Japan has increased. The currency volatility is occurring against a backdrop of broader market turbulence. The Tokyo stock market experienced significant selling pressure on November 21, with the Nikkei average falling by more than 1,200 points, according to NHK. The decline was attributed to overnight losses on the New York stock exchange, demonstrating how interconnected global markets affect Japan's financial landscape. This stock market weakness adds another layer of uncertainty for expats with investments in Japanese equities or pension plans tied to domestic markets. Market intervention, should it occur, would involve the Japanese government selling foreign currency reserves and buying yen to support its value. Japan has a history of such interventions, most recently in 2022 when the yen weakened beyond 150 per dollar. These actions can create sudden, sharp movements in exchange rates, potentially catching foreign residents off-guard if they're planning large currency transfers or international transactions. Financial experts advise expats to monitor the situation closely and consider their exposure to currency risk. Those planning to remit significant amounts of money internationally may want to consult with financial advisors about timing and hedging strategies. The current volatility suggests that waiting for more stable conditions—or acting quickly before potential intervention—could significantly impact the value of transfers. The government's willingness to intervene also reflects concerns about inflation imported through a weaker currency. Japan imports most of its energy and significant amounts of food, meaning a weaker yen translates to higher costs for these essentials. Foreign residents have already experienced rising prices for imported goods, and further yen weakness could accelerate this trend. As the situation develops, expats should stay informed about official announcements from the Ministry of Finance and Bank of Japan. Currency markets can move rapidly, particularly when intervention is being discussed openly. Understanding these dynamics and their personal financial implications will help foreign residents navigate this period of uncertainty effectively.