Bansenshukai (萬川集海, translated 'All Rivers Merge into the Sea') is a Japanese book containing a collection of knowledge from the clans in the Iga and Kōga regions that had been devoted to the training of ninja.
It was compiled by Fujibayashi Sabuji in 1676, in the 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, and along with the Shōninki of 1681 and the Ninpiden of 1655 make up the three major sources of direct information about this shadowy profession.
The books include:
- Two volumes of thought and philosophy
- Four volumes on leadership
- Three volumes on Yo-nin—open disguise
- Five volumes on In-nin—hidden infiltration
- Two volumes on astrology
- Five volumes on tools and weapons
There are two versions:
- The Koga Version has twenty-two chapters bound in ten volumes, with an additional one volume attached to it.
- The Iga Version has twenty-two chapters bound in twelve volumes with an additional four chapters in four volumes attached to it.
After World War II, a limited number of handwritten copies were offered to the public. A few of these copies are in some major national and university libraries. It has recently been re-translated in various languages including English, French, German, and Japanese.
- "The Book of Ninja: The first complete translation of the Bansenshukai", 2013, Antony Cummins & Yoshie Minami
- Bansenshukai. Ninjutsu.com. Accessed March 8th, 2012.
- "Martial arts of the world: an encyclopedia, Volume 2: Ninjutsu", 2001, Thomas A. Green
- Bansenshukai Archived December 24, 2005, at the Wayback Machine. Ninpo.org. Accessed March 8th, 2012.
- Antony Cummins & Yoshie Minami, trans. The Book of Ninja: The first complete translation of the Bansenshukai. London: Watkins, 2013.
- Bansenshûkai: le traité des dix mille rivières, Fujibayashi Yasutake, Axel Mazuer, Albin Michel, May 2013. (in French)