Bansenshukai (萬川集海) is known as the bible of ninjutsu and was written in 1676 by Fujibayashi Yasutake. the Bansenshukai translates out as "Ten Thousand Rivers Flow into the Ocean", and is a Japanese book containing a collection of knowledge from the various ninjutsu ryuja from the Iga and Kōga regions.

 

The Bansenshukai was written early years of the Tokugawa shogunate, to preserve the knowledge that had been developed during the near-constant military conflict from the Ōnin War until the end of the Siege of Osaka almost 150 years later. As well as information on military strategy and weapons, it has sections on the astrological and philosophical beliefs of the times. Along with the Shōninki (1681) and the Ninpiden (1560) make up the three major sources of direct information about historical ninjutsu.