The Japanese yen has fallen to a 40-year low due to rising US interest rates spurred by the war in Iran and a stronger dollar. The Bank of Japan’s lower interest rates compared to the Federal Reserve are driving capital flows towards the US, further weakening the yen. While the Japanese government attempted interventions earlier this year, they failed to halt the decline, and traders anticipate another intervention as the Fed signals potential rate hikes. This situation poses risks for Japan's import costs and cost of living, with potential implications for global markets, particularly impacting the “carry trade” in US stocks and increasing volatility.