Rare is the chart-topping group who hide their faces in order to keep their day jobs as dental hygienists. Yet that's the story of GReeeeN, a quartet from Fukushima Prefecture that debuted in 2007. Each member brings a different musical background and the result is a swirling blend of pop, rock, hip-hop and reggae with a fresh, upbeat sound. Anchored by guitars and tag-team vocals, their music has brightened the day of thousands of listeners across Japan.