Instructions on making a Kama

The Shinobi Hiden or Ninpiden is a ninjutsu manual written either around 1655 or in 1560, and attributed to either Hattori Kiyonobu or Hattori Hanzo. It is regarded as one of the three key historical texts of ninjutsu, along with the Shōninki and the Bansenshukai. It was passed down in the Hattori family, and was considered a secret transmission; it was not shared with outsiders and even within the family, few had access to it.