China has sharply curtailed exports of rare earths, germanium and other minerals vital to weapons production, according to a Wall Street Journal investigation. Beijing’s tightened controls, in place since early April, are aimed squarely at materials used in Western defense systems, even as it briefly relaxed broader shipments following trade concessions agreed with Washington in June. The squeeze is rippling through the U.S. and European military-industrial base. Contractors report delivery delays and spiralling costs for everything from small-caliber ammunition to jet fighters. Spot prices for several restricted minerals have jumped between five- and sixty-fold, while inventory levels at some suppliers are nearing exhaustion as firms scour alternative sources in Africa, Australia and North America. The disruption underscores the West’s dependence on Chinese supply: the country accounts for an estimated 80-90% of global rare-earth output, and more than 80,000 parts used in U.S. weapons systems incorporate the constrained materials. The latest curbs add urgency to efforts in Washington, Brussels and allied capitals to accelerate domestic mining and processing capacity and diversify strategic mineral supply chains.