This is a story that tells us about the attractive cultures and traditions of the homelands of Iga ninja and Koka ninja, where we can still feel the presence of real ninja. Many people from around the world are fascinated by ninja today, but who they really are is not well known. If you visit Iga and Koka, you will see old castles which retain the atmosphere of the warring states period in Japan on the outskirts of the village, training seminaries for Yamabushi traveling monks in the mountains where ninja also trained, and tutelary shrines in the villages where ninja gathered for conferences – you will see the true nature of ninja.

Images of real ninja emerging from the secret document of Iga-ryu and Koka-ryu ninja arts
The Bansenshukai is a secret document containing a collection of ninja techniques of the Iga-ryu and Koka-ryu Schools. It was compiled by Fujibayashi Sabuji Yasutake in 1676. He was a descendant of Fujibayashi Nagatonokami, one of the elite ninja clans of Iga. The book’s core philosophy is Seishin (honoring justice and loyalty) and the book is comprised of the volumes Seishin, Shochi, Yonin, Innin, Tenji, and Ninki. Manuscripts of the document are preserved in various places in Iga and Koka such as the Iga-ryu Ninja Museum.

"Bansenshukai" is a book on ninjutsu written in 1676 by an Iga ninja, Fujibayashi Dengoro Yasutake, which systematically details the ninjutsu and ninja weapons of the 49 schools of ninjutsu of the Iga and Koga.
It was named "Bansenshukai" (Ten Thousand Rivers Gathering into One Sea) because of the vast number of ninjutsu techniques compiled in the book, just as "ten thousand rivers gather into one sea".
As the name implies, the book describes many ninjutsu techniques, including the mindset of the ninja, various ways of hiding using natural terrain, and tools such as the water spider that crosses water and the roirogan hiya arrow that blasts away enemies with an explosion.

It is one of the most important ninjutsu books, and is also found in the famous ninja book “Bansen Shukai.
It was discovered on December 3, 2021, in the storehouse of Kuzugi Shrine in cooperation with Kuzugi Ward, after information was provided that a document belonging to Mabayashi Seiyo was found in Kuzugi Ward.

Since ninjutsu books are not of the nature required by village government in the Edo period, it is assumed that this historical document was originally handed down to a private family, perhaps a resident of Katsuragi, in which case it is quite possible that the family was related to ninja/ninjutsu in some way. It is highly possible that it eventually became one of the documents owned by the Katsuragi district for some reason. The possibility that the Koga samurai and Koga ninja families themselves may have passed down these documents to the Koga region is extremely important as one of the “down-to-earth, real ninja-related documents”.

The actual discovery of these cases has raised the possibility that other ward-owned and shared documents also contain or may have contained ninjutsu books. In the future, it will be necessary to conduct further material research based on this, and it is hoped that this will lead to the discovery of new ninja-related materials.