china stopped nearly all tungsten exports to japan and reduced rare-earth magnet shipments to may 2025 lows, explicitly timed to japanese prime minister takaichi's november 2025 comments about taiwan. china is using mineral supply chain leverage as a diplomatic pressure tool against a specific political statement by a specific foreign leader. tungsten is critical to defense manufacturing and cutting tools; the near-total cutoff is more surgical than the broader controls applied to other partners.