China mines about 70% of the world's rare earths but has a virtual monopoly on refining and processing. Even if the pace of export approvals quickens as Trump suggested, the new system gives Beijing unprecedented glimpses of how companies in a supply chain deploy the rare earths it processes, European and U.S. executives have warned.

At the center of the latest trade storm between the U.S. and China is He Lifeng. Since He became vice premier in early 2023, China's leader Xi Jinping has essentially put him in charge of fortifying the nation’s economy against the effects of U.

The scramble in recent weeks to secure export licences for rare earths shows China has devised a better, more precisely targeted weapon for trade war.