"The Dark Side of Japan" is the design language used on the Yamaha MT 15 . This design philosophy is focused on creating motorcycles that have an aggressive and powerful look, with a dark and menacing aesthetic. The design is inspired by Japanese anime and manga, which often feature dark and powerful characters with an aura of mystery and strength. The design language is reflected in the sharp lines, bold colors, and edgy styling of the Yamaha MT 15 .