"Through ninja, we want to revive our communities," says Eikei Suzuki, the governor of Mie prefecture, who joined his colleagues in donning the black attire. The Mie region includes the city of Iga, often referred to as the "home of ninja" because it had a famed school of ninjutsu - or ninja techniques. Mie University even offers a course in ninja studies, which includes lessons in how to walk stealthily. Ninjas were traditionally mercenaries hired by warring states in the 15th and 16th centuries, before Japan was unified. While they were skilled in armed combat and famed for being able to "disappear", experts say they tried to avoid fighting wherever possible - espionage and intelligence gathering were their main strengths.