Shinobi Hiden, or The Secret Ninja Tradition, is a manuscript said to have been passed down in the Hattori family of Hanzo Yasunaga??????, who served the shogun Ashikaga Yoshiharu, and after the Tokugawa clan, in the Mikawa area. Shinobi hiden is an excellent source for those who want to study ninjutsu in its historical context. It is full of fascinating information and shows the ninja tools and skills that have been kept secret for so long.