China’s exports of four key materials to Japan in June all went to zero.

The four materials are gallium, dysprosium, terbium, and yttrium.
Gallium is used to make chips, dysprosium and terbium help rare-earth magnets in electric vehicles and industrial equipment withstand high temperatures, and yttrium is used in heat-resistant coatings for aircraft engines and power-plant turbines.
Although Japan is a major producer of rare-earth magnets, some upstream raw materials still need to be purchased from China. In May, Japan still received 6,000 kilograms of Chinese gallium, but it went to zero in June.
The data the customs authorities released today is for June.
Meanwhile, China’s total exports of rare-earth magnets were still increasing during the same period, but Japan received zero of all four of these upstream materials.