The Shoninki was written in 1682 by Natori Masazumi, and consists of three volumes. The Shoninki is a text of Kishu-ryu ninjutsu, and it is said that Iga warriors who escaped the Iga region after their defeat in the Tensho War, established this ninjutsu tradition. Although it seems that Kishu-ryu branched from Iga-ryu, there are fundamental differences that create a clear distinction between these traditions. In any case, the text itself covers a number of subjects, from strategy to infiltration, but not specific fighting techniques. Although the text is not very long, it reflects a certain way of thinking about ninjutsu, which is most interesting to anyone who wishes to learn more than just techniques.
The Shoninki is divided into Preface (Jo), three scrolls (Shomaki, Chumaki, Gemaki) and an epilogue (Okusho).
In the preface, the author discusses the different types of spies and the principles of espionage.
The first scroll addresses basic skills, such as disguise and concealment, house-breaking and information gathering. The second part deals with defence against enemy spies, human nature, physiognomy, recognizing and eliciting the true intentions of people and laying false trails and cluess. The final scroll is concerned with one's own emotional states as well as those of other people.