A shortage of critical minerals is starting to affect the broader Japanese economy, adding a sense of urgency for Prime Minister Sanae Takaichi's government to find alternatives to exports that China has cut off, according to recent corporate filings. China dominates the global market for rare earths - which are crucial in making items from electric cars to weapons - and it is using those supplies as a diplomatic cudgel. Since Takaichi enraged Beijing with comments about defending Taiwan in November, Beijing has choked off shipments of certain key minerals to Japan.