One book explaining the knowledge of this group has a name that translates as Sea of Myriad Rivers    Merging. Its two schools were Iga and Koga until those were broken up by
One book explaining the knowledge of this group has a name that translates as Sea of Myriad Rivers    Merging. Its two schools were Iga and Koga until those were broken up by Oda Nobunaga. The  weapons these people used included straight swords and shuriken, which are thrown weapons that   contain blades in the shape of a star. These people were sometimes contrasted with the more upper  class samurai, though some individuals took both roles, and they are sometimes called shinobi. Name  these Japanese spies who, contrary to popular belief, rarely wore black.
One book explaining the knowledge of this group has a name that translates as Sea of Myriad Rivers    Merging.