Japan says it is ready to take action after the yen falls to its weakest level in about 40 years. Multiple reports say the yen breaks past key levels in early trading in London on Monday, reaching more than 161 yen per US dollar, a level not seen since 1986. The Japanese government and relevant authorities state they monitor currency moves closely and are prepared to respond if necessary, without specifying the exact measures or timing. The remarks come as market participants react to ongoing global factors affecting exchange rates, pushing the yen weaker against the dollar. The latest move underscores volatility in foreign exchange markets and keeps attention on whether Japanese authorities will intervene directly or use other policy tools. The situation remains fluid as traders watch subsequent yen movements and any follow-up statements from Japan’s officials.