"Ninjutsu recorded in Books of Secrets" (1st Term) (summary)
Lecturer: Yuji Yamada
Books of Ninjutsu secrets are originally handed down exclusively among Ninja, and no one outside of the tribe was allowed to look at them. Therefore, very few books are confirmed their existence. This may be the cause of many tricks being referred to as the art of Ninja, even though many of them are unfounded and not documented in textbooks for Ninjutsu.
This report intends to elucidate on the manners of sneaking-in, which is the core activity for Ninja, while introducing historical materials that are not reprinted. For example, "用間加條伝目口義(Yokankajodenmoku Kugi)" describes that a Ninja basically must follow behind another person, like a flea or lice, in order to sneak into a building. Swimming across the moat or climbing over the wall becomes one of the choices only after the basic technique turned out to be not available. When climbing over the wall, it shows that you shall tie the strap of the sword onto your ankle before setting it against the wall, then, by stepping on the brim of the sword, you shall jump up to the bracket of the wall. It also explains that when you jump off from a high ground, if you try to jump up a little upon landing on the ground, you will be able to land safely and without making noise. It suggests that it is also useful to wear a fire hook, a wooden stick or anything long, like you would wear a sword, then to hold it under your arm with about a foot of it sticking out when you jump. If you cannot find anything long to hold, it suggests that wearing a sword with a piece of gold put on the tip of its sheath can be a good substitute. All of these descriptions are never nonsensical in its contents, but rather written with the practicability that is achievable through training.