The tasty Japanese seaweed nori is ubiquitous today, but that wasn't always true. Nori was once called “lucky grass” because every year's harvest was entirely dependent on luck. Then, during World War II, luck ran out. No nori would grow off the coast of Japan, and farmers were distraught. But a major scientific discovery on the other side of the planet revealed something unexpected about the humble plant and turned an unpredictable crop into a steady and plentiful food source.