linguistic:voice_change, structural:scholar_edition, structural:reformatting
Oniwaban

In the early 18th century, shogun Tokugawa Yoshimune founded the oniwaban ("garden keepers"), an intelligence agency and secret service. Members of the oniwaban were agents involved in collecting information on daimyō and government officials. The secretive nature of the oniwaban —along with the earlier tradition of using Iga and Kōga clan members as palace guards—have led some sources to define the oniwabanshū as "ninja". In 1649 record Tokugawa shogunate law on military service, The shinobi was considered as profession, as only daimyōs with an income of over 10,000 koku were allowed to employ ninja or shinobi. In the two centuries that followed, a number of ninjutsu manuals were written by descendants of Hattori Hanzō as well as members of the Fujibayashi clan, an offshoot of the Hattori. Major examples include the Ninpiden (1655), the Bansenshūkai (1675), and the Shōninki (1681).