A small town in the Netherlands hosts the only factory that produces the only chip-making machines that generate a type of light found nowhere naturally on Earth: extreme ultraviolet, a light emitted by young stars in outer space. This light, known as EUV, is the only way to make one of the world’s most valuable and important technologies at scale: cutting-edge semiconductor chips. The factory is forbidden from selling its EUV machines to China. Below we explain how the chips are made, why they have become the focus of the US-China trade wars, how Taiwan was drawn into the maelstrom,...