Ninja and Ninjutsu (3): The Bansenshukai – The Encyclopedia of the Shinobi
Updated: 3 hours ago
The series at a glance
The Bansenshukai – the encyclopedia of the shinobi (this part)
Most of what has been written about the ninja was written by others: storytellers, playwrights, novelists and directors. The Bansenshukai (萬川集海) is one of the few places where the shinobi tradition speaks for itself. Its name means "ten thousand rivers gathering into one sea", and the name itself explains the intention: to gather into one treatise the knowledge of many streams, mainly those of Iga and Koga.
When and who
The treatise was completed in 1676, about seventy years after the end of the age of wars. It is attributed to Fujibayashi Yasutake, a descendant of the Fujibayashi family of Iga. The catalog record of Iga City notes that the Iga copy names only "the monk Fujibayashi", so some researchers see it as a work passed down within the family rather than a book by a single author.
The date matters for understanding the treatise. It was not written by a shinobi in wartime but in a time of peace, when this knowledge was disappearing. Sometimes it also served as a certificate of lineage. According to the Japan Tourism Agency's explanation database, in 1789 "the old remnants of Koga" traveled to Edo and presented the Bansenshukai to the shogunate to prove their lineage and their profession. They received money and returned with it to their families. The National Diet Library of Japan dates a presentation of the treatise to the shogunate by Koga warriors to 1854. There may have been more than one presentation. I have not found a source that reconciles the two dates.
The structure of the treatise
The treatise has 22 volumes. The first volume contains a preface, an explanatory chapter, a table of contents and a chapter of questions and answers. The other volumes are divided as follows:
Part | In Japanese | Subject | Volumes |
Seishin | 正心 | "The correct mind": ethics, loyalty and the purpose of the shinobi | 2 |
Shochi | 将知 | What a commander needs to know: running spies, signals, passwords and defense against enemy spies | 4 |
Yonin | 陽忍 | "Open stealth": infiltration in disguise and under a false identity, in daylight | 3 |
Innin | 陰忍 | "Hidden stealth": infiltration at night, into castles and camps | 5 |
Tenji | 天時 | "The timing of heaven": weather, stars, calendar and navigation | 2 |
Ninki | 忍器 | Tools: climbing, crossing water, breaking in and fire | 5 |
The structure alone shows that the treatise begins with ethics and leadership, not with tools. The tools come at the end.
What is inside: a journey through the volumes
To understand what is really in the Bansenshukai, I followed the treatise's full table of contents and the translations of the preface and of several chapters. Both were published by the Iga-ryu Ninja Museum in its database. What appears here in quotation marks is my own free translation.
The first volume: preface, explanation, questions and answers
The preface opens with the first sentence of The Art of War, the classical Chinese military treatise attributed to Sun Tzu: "War is a great matter for the state, the way of life and death, of survival and ruin". From there Fujibayashi builds his argument: even a capable commander will fail if he does not know what the enemy is secretly planning. The way to know this is Ninjutsu. In his words, one person acting correctly can bring about the destruction of an entire army. The preface is signed in 1676 by "Fujibayashi Yasutake, a monk of Koka District in Omi". The National Diet Library of Japan notes that in the treatise he is presented as a man of Koga, but his ancestors' memorial stone is in Iga, so he was probably from Iga. At that time the border between the two regions was not sharp.
In the explanatory chapter (凡例) Fujibayashi describes his method. He collected the techniques and secret tools of eleven shinobi from Iga and Koga, discarded what seemed weak to him and added strategies of Japanese and Chinese generals. He also explains openly that he did not spell everything out: whoever learns from the book without a teacher will not reach the secrets, because these are passed on orally. This is the origin of the note "kuden" (oral transmission) that recurs in the book.
One of the eleven masters he lists is Shimotsuge no Kozaru, "the monkey of lower Iga". According to the National Diet Library of Japan, the treatise tells that Kozaru entered a castle through a water drainage channel, set it on fire and brought about its fall.
The chapter of questions and answers (術問答) is especially interesting, because in it Fujibayashi asks the questions we ask too. When did Ninjutsu begin? The answer attributes it to Fuxi and the Yellow Emperor, legendary rulers of ancient China, but admits at once that the ancient books have no direct record of it. Why is it essential in war? Because without knowing what the enemy is planning, one cannot choose a tactic. What is it called in China? Jian (間), "gap", because the agent penetrates through the gaps in the enemy's defenses. The same word also means "to separate", because the agent sows discord between the enemy and its allies. As a Japanese example, the treatise brings Kusunoki Masashige, a 14th-century general who is regarded in Japan as a symbol of loyalty, and who according to the treatise kept 48 agents in Kyoto in three groups of sixteen. And the last question: why is the Japanese name shinobi? Because the character 忍 is built of a blade (刃) above a heart (心), and that, in his view, is the heart of the matter.
The correct mind (Seishin): volumes 2–3
"The root of the shinobi art is the correct mind, and its end is stratagem and deception." With this sentence the Seishin part opens, and it explains the order of the whole book. Whoever teaches deception must begin with ethics; otherwise he has taught thieves. The correct mind is defined by four virtues of Confucian origin: benevolence, righteousness, loyalty and sincerity. Fujibayashi quotes the Great Learning, one of the foundational texts of Confucianism: "When the mind is not present, we look and do not see, we listen and do not hear." And he states that the shinobi art is not meant for personal gain or for the service of a lord without morals. Whoever does so will be exposed. And if he is not exposed, it will harm him in the end.
The practical articles in this part are surprising. The shinobi needs a calm face, because "a calm face is the beginning of a wise stratagem". He must always be trustworthy and not lie even in jest, because a man whose words and deeds do not match will be abandoned. Here the paradox of the profession appears: the one whose job is to deceive the enemy must be completely trustworthy in the eyes of his own people. But trustworthiness, too, has a limit. The treatise tells the story of the Chinese Wei Sheng, who promised to meet a woman under a bridge, did not move when the water rose and drowned. According to Fujibayashi, trustworthiness without judgment is not a virtue.
The second part of the Seishin is called "the blade of the heart" (刃心). It deals with endurance: whoever loses himself over a small insult shows "the courage of a common man". The example is Han Xin, who in his youth agreed to crawl between the legs of a bully so as not to be drawn into a brawl, and who later became a general of the Han dynasty commanding tens of thousands. The part also instructs to keep away from wine, lust and greed, because they "steal the true heart", and many reveal secrets because of them. Finally, it distinguishes between "the courage of blood", born of momentary anger and quickly fading, and "the courage of righteousness", which comes from a sense of duty and keeps a person steady. I wrote about the meaning of this part for Ninpo in the article Ninpo and Ninjutsu: What Is the Difference? (in Hebrew)
What a commander needs to know (Shochi): volumes 4–7
This part is addressed not to the shinobi but to the one who employs him. Fujibayashi explains in the preface that even a skilled shinobi will fail if the commander does not know how to use him. The table of contents lists "three prohibitions in Ninjutsu", secret writing, letters sent tied to an arrow, agreed signals, agreements between the commander and the shinobi that guarantee his safety, and the way to recruit shinobi.
The second half of the Shochi deals with what we would today call counterintelligence: how to prevent enemy shinobi from getting in. It has "five articles: do not employ the enemy's shinobi", rules for guard fires, passwords and identification signs, guard procedures, night patrols and even "tools for preventing the entry of the enemy's shinobi". Whoever wrote this part knew that the enemy reads the same books.
Open stealth (Yonin): volumes 8–10
According to the Japanese encyclopedia Nipponica, yonin is infiltration into the enemy camp "openly, by means of a stratagem", that is, under a false identity rather than by hiding. The first volume in this part is called "entering from afar", and it deals with actions that begin long before the war. The names of the techniques are poetic: "the man in the moon", "the shadow figure", "the villagers", "the worm in the body", "turning the sack inside out", "the light of the firefly", "spitting at the sky", "the slack bow" and "the echo". What each name conceals, the treatise explains only in part, and the rest is passed on orally.
The second volume is called "entering from close by". It deals with matching the enemy's passwords and identification signs in order to blend in among his men, and with techniques such as "the moon on the water" and "entering through the valley". The third volume, "the observing eye", is a practical guide to observation: how to estimate the depth of a river, a rice field and a moat, how to tell whether a castle is well defended, how to estimate the size and deployment of the enemy army and how to detect an ambush. According to the explanation in the first volume, the shinobi must "see and hear all the time".
Hidden stealth (Innin): volumes 11–15
Innin is the infiltration most people imagine: according to Nipponica, entering "in secret, exploiting the enemy's weak points". The first two volumes deal with infiltrating castles and camps, including arson. The third volume, "infiltrating a house", shows how practical the treatise is. It has articles on people's sleeping patterns in each season, on estimating the depth of sleep by age and mood, on dealing with dogs, on ways of walking, on neutralizing noise, on "the nights on which one should enter" and even on "listening to snoring" to know whether a person is really asleep.
The fourth volume is devoted to opening doors: how to identify the type of bolt by touch, how to remove it, how to identify hinges and locks of different kinds and how to open them. The fifth volume deals with the night raid: advance reconnaissance, departure, orders, planning, timing and "twenty-one articles on capturing people".
The timing of heaven (Tenji): volumes 16–17
The first volume in this part deals with tonko (遁甲), a Chinese divination method for choosing suitable days, hours and directions for action. The second volume is more practical: forecasting wind and rain, calculating the times of moonrise and moonset, tide tables, finding direction on a dark night and measuring time. Fujibayashi himself plays down this part. He quotes the Chinese principle according to which timing matters less than terrain, and terrain less than unity among people.
The tools (Ninki): volumes 18–22
The tools are divided into four groups. Climbing tools: many kinds of ladders, such as the knotted ladder, the flying ladder and the folding ladder, as well as the kunai, a metal spike for digging and climbing, hooks and ropes. Water tools: a floating bridge, a reed raft, a raft of jars, the mizugumo ("water spider") and fins. Breaking-in tools: saws, drills, lock-opening tools and a "listening iron". And fire tools: torches that do not go out, lanterns, "fire that burns in water" and recipes for various substances, among them a "recipe for deep sleep".
According to the explanation in the first volume, the tools come at the end because they are craft, not principle. Fujibayashi adds two rules: every shinobi must prepare and test a tool himself before using it, and a simple tool that serves several purposes is preferable.
There is an interesting debate about the mizugumo. Antony Cummins and Yoshie Minami, who translated the treatise into English, presented in a 2014 lecture at Mie University the interpretation that it is not "water shoes" but a floating seat, used together with the fins that appear next to it in the same volume. I write below about the doubt whether it worked at all.
How far can it be trusted?
The Bansenshukai is a first-rate source, but it is not a record of what shinobi actually did in the Sengoku period. There are three reasons for this:
The first is timing. As I wrote in part one, the treatise was written after the Iga wars, after the world in which the shinobi operated had disappeared.
The second is Chinese influence. Prof. Takamura Takayuki of Meiji University compared the treatise with the Chinese military encyclopedia Wubei Zhi of the Ming period and found a great similarity in the tools. His conclusion is that it is hard to say all the material is a faithful description of shinobi from Iga and Koga. The researcher Rob Tuck notes that the Chinese treatise reached Japan before 1664 and that it deals with battles and sieges, not with stealth. Antony Cummins, the English translator of the treatise, argues that Fujibayashi used the Chinese sources to strengthen his points rather than copying from them.
The third is the tools themselves. The best-known example is the mizugumo, the "water spider", a device meant for crossing water. Tuck shows that according to the measurements in the treatise it could not have floated, and that the versions that work in museums and videos differ from the original description. Some of the tools may have existed only on paper. (A thought worth keeping in mind: this was a secret teaching, and although the book was written in a time of peace, it is reasonable to assume that suspicion and vigilance continued among those who carried the tradition on. So it is very likely that not all the secrets were written down and published, and likely that some were deliberately distorted. The same may apply to the "water spider"...)
What comes out of all this? It is better not to read the Bansenshukai as a technical manual. It is better to read it as a treatise that shows how the tradition saw itself at the end of the 17th century: what was considered important, in what order and why. And there it is especially interesting, because it places ethics and intelligence before the tools and before the fight.
A discovery from 2021
In the preface Fujibayashi mentions an earlier treatise called Kanrin Seiyo (間林清陽) and incorporated parts of it into his book. For years no copy of it was found. According to the Japan Tourism Agency, in 2021 a handwritten copy dated to 1748 was found in Koga. The find makes it possible, for the first time, to check what the Bansenshukai took from an earlier source.
In the next part: why the Bujinkan stopped calling itself "Ninjutsu".
Sources
Iga-ryu Ninja Museum and Iga City: 萬川集海, catalog record.
Antony Cummins and Yoshie Minami, The Book of Ninja: The Bansenshukai, Watkins, 2013.
Rob Tuck: The Shinobi's Ancient Chinese Secrets and the mizugumo mystery solved, Critical Ninja Theory.
Inside Ninjutsu: Bansenshūkai at 350, 2026 (summarizes Takamura's position).
Japan Tourism Agency, multilingual explanation database: The Bansenshukai and the Kanrin Seiyo and The remnants of Koga in Edo, 1789.
Iga-ryu Ninja Museum, ninja database: Table of contents of the Bansenshukai, including the preface, the explanatory chapter, the questions and answers and the Seishin chapters.
National Diet Library of Japan: Secret books: let's read Ninjutsu treatises (in Japanese).
Encyclopedia Nipponica, entry Ninjutsu by Watanabe Ichiro: Kotobank (in Japanese).
Antony Cummins and Yoshie Minami, lecture at Mie University, 2014: The Bansenshukai Back to Life.
Cover image: National Archives of Japan, terms of free use of the archive's images.
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