On June 19th, 2022, municipal government officials in 甲賀市 Kōka City, Shiga Prefecture, famous for being a center of ninja heritage, announced that a manuscript of the Edo period ninjutsu book 間林清陽 Kanrinseiyō had been discovered.

The book is said to be the basis for the 万川集海 Bansenshūkai, a representative ninjutsu book that served as a dictionary of the ninja arts of the Kōka and Iga regions. The Bansenshūkai clearly stated that it used the Kanrinseiyō as a reference point. However, neither the existence nor the contents of the legendary ninja sourcebook had been confirmed until now.

The image below shows the title page of the 40-page manuscript, which indicates on the left: 軍法間林清陽巻中 meaning "Tactical Strategy (Book) Kanrinseiyō, Middle (Second) Volume." Penciled in on the right is the date when this manuscript is believed to have been transcribed, 延享五年, the 5th year of the Enkyō in the Edo Period, which corresponds to 1748.

According to Sankei News, the manuscript contains 48 articles on ninjutsu including practical teachings such as how to make 撒き菱 makibishi caltrops out of bamboo, how to fight when dealing with multiple enemies, how to discern faint sounds and how to make silent footwear.

As for 呪術 jujutsu (spells), for example, it contains a spell to stop guard dogs from barking which involves writing the character 鬼, meaning demon, and "cutting nine syllables" (the nine ninja hand gestures).

Another spell contained within the manuscript is for quickly hiding oneself from someone. This may be familiar to those who have seen ninjas in films, manga or anime. If you ever wondered about the powder that ninjas throw down on the ground to hide themselves, this could be it. According to this spell, you should throw down a powder made of charred owl and turtle in the direction of the person you wish to hide from, cut the nine syllables, then hide behind the nearest object.

福島嵩 Takamasa Fukushima, 37, a member of Kōka City's regional development volunteer brigade who has been researching ninja, discovered the scrolls last December in a district-owned warehouse in the city's Kazuraki district. It may have been a document handed down in the home of a descendant of the Yoshikawa ninja clan that served the Owari Domain and lived in the same area.

According to the official in charge of cultural property at the Kōka City Office, "now that Kanrinseiyō has been featured in the media, some citizens of Kōka may search for the other volumes in their own homes or warehouses. Expectations are high that the other volumes will also be discovered."

As for the significance of the discovery, in addition to confirming the existence of the sourcebook known to be the basis for the Bansenshūkai, ninja fans and researchers are "particularly excited that it was discovered in Kōka City, the home of the ninja, that it contains a great deal of practical knowledge and that it can now be considered to be one of the oldest ninjutsu books in existence."

Although there are no plans to publish the Kanrinseiyō, the city plans to display a reproduction of the manuscript at the 甲賀流リアル忍者館 Kokaryu Real Ninja-kan tourist information center.