History: Ninjutsu and Kuden: Why the Art Was Never Truly Secret

The term kuden is made up of two ideograms, ku 口 — mouth, and den 伝 — transmission. It is a far-reaching concept, closely bound up with the Japanese Way and with the arts, whether martial or otherwise. It is strongly present throughout shinobi no jutsu [ninjutsu], yet in discussion it is passed over and, for the most part, only half understood.

Many people hold the mistaken notion that the manuals of ninjutsu are written in a cipher, handed down orally so that the secrecy of their contents might be preserved. Sometimes the scrolls consist merely of lists of skills and tools, and this creates the illusion of some kind of code. But this interpretation is wrong, save for a few examples — such as information on the ingredients of certain explosives.

The meaning of the individual names may have been plain fact to anyone versed in the military terminology of the period in which a given scroll was composed. That we do not understand these names today does not mean they were equally obscure to the people concerned in the past. To attach the word kuden to certain skills makes the skills without it general knowledge — or at least intelligible to the people of a given school and age.

Most instructional manuals contain detailed information with a reference to further skills that are to be passed on orally. A ninja manual is almost always highly informative, but with a touch of hidden meaning, or a secret subtext. Everything considered too secret to be written down is likewise marked as kuden.

Ninjutsu itself was never secret!

To pay a local inhabitant for information was regarded as ninjutsu, just as was sending some man to observe the banners and identifying marks of an enemy army. Shinobi no jutsu is in essence a series of levels with loose boundaries between them. Some techniques were known to many students, others only to a chosen few. The closer you came to the head of a school's system, the closer you came to its deep secrets. Both the Shinobi Hiden and the Shōninki speak of sharing the deepest secrets with only one person — and by this is meant not merely a member of the family, but the one who shows the greatest aptitude for the work of the ninja.

"If you have children or grandchildren who are not good enough, or do not have the right mindset, then they should not receive the complete traditions of ninjutsu, and certain skills should be kept hidden from them. And to one chosen person alone should they be given in their fullness." Ninjutsu Ōgiden, 1586

Ninjutsu, however, was not always handed on to just one person. A whole generation of men from the province of Iga was hired to teach others the art of the ninja across most of the Japanese armies. About fifty ninja were hired in this way in each province, which gives hundreds, even thousands, of schools. How else could the demands and needs of an entire country have been met, if only one man of a single generation acquired the knowledge of ninjutsu?

In history we find no Japanese schools whose content was handed on in secrecy, or built solely on an oral tradition, with the exception of the Ōgiden manual mentioned above, where parts of the inner mechanisms are passed to only one person per generation. Only a small percentage of the teaching's content was kept secret in this way from its members. It must be understood, however, that certain parts of the teaching were meant to be understood only by the students of the school that had gathered those skills. In this sense, kuden may be divided into three kinds:

• [1] Skills that are known to most of the people engaged in military operations, and to those who concern themselves with shinobi no jutsu or are themselves shinobi soldiers. These are skills such as reconnaissance, topography and the arts of measurement — in short, the elements used by an entire army.
• [2] Skills whose effect is understood by everyone — explosives, say, or the techniques of night raids — but whose detailed particulars are not commonly known. The path to these skills, not their result, is the kuden, and it is known only to a select number of those engaged in this activity.
• [3] Skills that are a deep secret and are passed only among a few, very few, members across a school. The people who are the target of their effect are ignorant of their application — such as eavesdropping on conversations from within an enemy fortification without the agent being detected, techniques of infiltration and the making of sleeper agents, or the mystical elements kept for the more advanced students.

Kuden appears throughout Japanese culture, and this is one of the reasons for the loss of some of the finer details of the art of the ninja. All the teaching lineages have died out, and we no longer possess a living oral tradition with a verifiable background.

For the reader from the Western world it is best to see kuden as the oral transmission of information from teacher to student, meant either to keep a secret or to indicate something too complex to be written down.

On the sources: The period manuals cited above (Shinobi Hiden / Ninpiden, Shōninki, Ninjutsu Ōgiden) are available today in the modern English translations of Antony Cummins and Yoshie Minami. Japanese terms and names are given in the standard (Hepburn) romanization.

History: Ninja or Shinobi? Correcting the Myth of Japan's Shadow Warriors

The reading of the characters 忍者 as shinobi rather than ninja is assured when these characters appear in certain grammatical positions. We cannot say today precisely how the medieval Japanese read these ideograms. There is, however, a strong argument for shinobi no mono, especially where phonetic markers are available to aid the reading. The term shinobi begins to appear in historical documents in the 14th century and undoubtedly predates the word ninja.

From the standpoint of modern reading in English, "ninja" has become the familiar, fluent form, while shinobi — though the more correct term — is less widely known and carries fewer popular connotations. For this reason I use both terms throughout this article, switching between them as convenient.

Equally debatable are the ideograms that may be read as ninjutsu or shinobi no jutsu, by which we mean the art and skills of the ninja. Both versions are correct, but the phonetic markers on period documents show shinobi no jutsu as the proper reading, given that we have no records of words read as ninjutsu.


Shinobi No Mono

Myths: Many enthusiasts of ninjutsu today hold that the term ninja denotes a social class, like the term samurai, and in doing so they ignore important historical facts. This mistaken interpretation also gave rise to the myth of an "eternal struggle" between samurai and ninja, in which the samurai stood for GOOD and LIGHT and the ninja for DARKNESS and EVIL. According to such people, ninja existed as a parallel "shadow" military class with its own distinct hierarchy and codes, differing from those of the samurai; the ninja supposedly performed tasks the samurai could not, because the code of Bushidō and other laws forbade them to him. Where and how this fabrication arose is hard to pin down, but a large share of this disinformation within the shinobi no jutsu community is carried on the backs of the very teachers and instructors the world over, Japan included. Through their superficiality and greed they created the 20th-century ninja who confuses generations of young people to this day.

Facts: Soldiers of the shinobi were recruited from various social strata of medieval Japan, but broadly we may say that most ninja came either from the ranks of the lower samurai class or from the foot soldiers known as ashigaru. We may also say that the term shinobi was the name of a profession and a set of skills — just as today a physician is a physician and a smith a smith — while the level of those skills is not defined by it in any way. It is today established that ninjutsu was mastered even by high-ranking samurai, such as Uesugi Kenshin, called the Dragon of Echigo, and likewise his enemy "twin," the Tiger of Kai, the great Takeda Shingen himself. All the battles of medieval Japan were decided by the use of ninjutsu to a far greater degree than is officially acknowledged today.

On the basis of analysis of historical documents, two main categories of ninja emerge, which unfortunately are not distinguished grammatically. The only way to identify which shinobi is meant is to grasp the context of each historical reference.

• [1] A shinobi may be a man or a woman without any training, simply someone used for their innate abilities, however slight. For example, a person with a good memory may be used as a shinobi to record a mental image of a particular space, or a person with a good knowledge of a specific province (kyōdō) may be called upon to gather information of any kind in that land. This untrained individual is regarded as a ninja by the tacticians of medieval Japan, but is not what we would consider a ninja from our modern perspective.
• [2] The archetypal figure of the shinobi no mono — a man trained in the skills set out below, to whatever degree, and employed as needed by a general or by the daimyō himself.

It is important to realize that, on the one hand, the term shinobi may denote a relatively incapable person sent on some mission at a lord's whim, while on the other, shinobi may designate a group of highly qualified individuals, specialists engaged in covert operations that made them today's legends.

Very often the word ninja also appears with two epithets, "ninja as assassin" and "ninja as spy," both of which deserve correction, as they do not match the whole truth. Ninja were indeed used as assassins, but the evidence for this activity is scant and represents a very small part of their sphere of operation.

The shinobi was first and foremost a skilled maker and user of explosives and poisons, an arsonist and a saboteur; he could also break into fortified seats to steal property or information. He gathered information by eavesdropping, but also by theft. Occasionally he eliminated the inhabitants of target seats. Under cover of darkness he served as a guide for assault units in "no man's land." These skills are known collectively as In-nin. He also played the role of messenger, using secret codes to convey messages by sound, by symbols and by written text.

The ninja was NOT trained as an assassin; his primary task was "information-gatherer," and if opportunity arose, or if the situation required it, he was used as an assassin. The evidence points rather to the destruction of entire families (clans) and their homes, not of individual human targets.

Ninja were recruited from every social stratum of the population, but mostly came from families of the lower samurai classes and served in the retinue of a clan leader. As part of samurai culture, shinobi soldiers were specialized as far-ranging scouts and secret agents who infiltrated enemy lines and carried out espionage and sabotage. In an army, one shinobi was reckoned for roughly every hundred men. Their physical, military and combat skills were no different from those of their fellow samurai.

Besides various bujutsu (martial styles), they also trained in different non-combat skills, so that on their missions they could appear in the roles of street vendors, merchants, actors, vagrants, hired swordsmen, and even priests and monks. These non-combat skills we call Yo-nin.

Spies have existed as long as wars have been waged, but the shinobi (also called in Japan Yato, Yushi, Kanja, Kagi, Kamari, Kyoudan, Onmitsu, Oniwaban, Suppa, Rappa, Fuma, Iga No Mono, Koka No Mono, Nokizarru, Monogiki, Mitsumono and others — depending on the period or province) operated on the Japanese and Far Eastern scene from roughly the end of the 14th century, when the Chinese Kan (Cho, Saisaku or Yutei) was "Japanized," until he gradually vanished in the turmoil of the Meiji reforms in the 19th century. He was replaced by a combination of modern spies and special army units, where the spy plays the role of informant and the special unit provides the striking force of attack. This division of the two main spheres of the ninja's work finally pushed these legendary men off the scene.

When the Tokugawa clan took control of Japan in 1603, the country entered a period of relative peace and totalitarian control. The shinobi no mono, as a decisive force on the battlefield, was no longer needed, and so their use shifted more into the sphere of espionage and counter-espionage.

The decline of their popularity hastened the activity of leading ninja in compiling records to preserve their teaching. In 1676 a shinobi named Fujibayashi Yasutake, who came from a samurai family, probably from Iga province, completed work on his masterpiece — a collection of information on shinobi no jutsu that he had gained through personal experience. This collection is today known as the Bansenshukai.

"In principle, the greatest and deepest secret in the shinobi traditions is contained in the chapter 'The Use of Spies' in The Art of War by the Chinese strategist Sun Tzu.
If you do not study this text thoroughly in every detail, and think that what is essential for the ninja are the various 'admirable' skills — such as crossing a water moat or a high wall — then you will be entirely off the mark and will, as the saying goes, put the cart before the horse." Fujibayashi Yasutake


GOKAN – THE FIVE SPIES

• Inkō No Kan — Local spies — Their purpose is to gather information and achieve their aims by using the local dialect. This is the same as the Japanese skill called dakkō, which literally means "copying from the mouth" and is a method of espionage, deception, or information-gathering through a good knowledge of the local dialect.
• Nairyō No Kan — Internal spies — Their aim is to lure a member of the enemy's retinue, or someone close to the enemy, and use him for one's own ends. A good internal spy will carry out his tasks thoroughly and precisely. But beware: the enemy may use this technique on you, winning over one of your men as his ally. Only rarely does one succeed in planting such a spy in the enemy's ranks; to do so means you must prepare them years in advance and with the utmost care, directing and controlling them before they are truly needed.
• Hantoku No Kan — Converted spies — Here it is a matter of captured enemy spies and their use for our own ends. Through them you can obtain exceptionally excellent information. In Japan this is called kaerinin or sorinin. You can use enemy shinobi agents by feeding them false information, which allows you to manipulate your enemy's plans to your advantage. It is precisely these converted spies whom, according to Sun Tzu, you should reward most liberally.
• Shichō No Kan — Doomed, or expendable, spies. They are those to whom we deliberately pass false information so that they carry it to the enemy. When the enemy uncovers the deception, these spies usually perish — sacrificed for the sake of the ruse.
• Tensei No Kan — Surviving spies are those trained in sabotage and reconnaissance carried out by infiltrating enemy lines and positions. This is the archetypal shinobi no mono from our modern perspective.

What follows from this short treatise for today's ninjutsu enthusiasts?

• [1] Ninjutsu is not a physical martial art — meaning a standalone fighting style — and it contains no instructions on how to fight man to man. It is rather a supplementary education of the samurai, encompassing specific tactical and strategic principles of obtaining and using information to defeat the enemy.
• [2] The practical combat disciplines practised by the samurai, and thus by the ninja, were kenjutsu (swordsmanship), iaijutsu (the art of the quick draw), yarijutsu (the art of spear fighting), kyūjutsu (archery), yabusame (mounted archery), shurikenjutsu (the throwing of short straight blades), taihojutsu (arresting and binding), bajutsu (horsemanship) and many others.
• [3] The shinobi soldiers formed no special social class of medieval Japan. A ninja could be anyone, at any social level.
• [4] The designations jonin (upper ninja), chunin (middle ninja) and genin (lower ninja) likewise do not refer to social status, as is often wrongly interpreted, but to the range of knowledge, experience and skill.
• [5] Ninja, or properly shinobi, is a term reserved for medieval Japan and the Japanese. It follows that no one today can become a ninja. Everyone, however, may study the period documents and in their free time revive the traditions of these soldiers, as various groups of historical fencing, period crafts and traditional Japanese martial skills do.

To serious students of ninjutsu I recommend studying the following historical documents, which were also the source for this article:

• Yokan Denkai and Yokan Rigen — Study and traditional commentaries on the 13th chapter of The Art of War by Master Sun Tzu,
  by Chikamatsu Shigenori, 1736
• Bansenshukai — "The Sea of Myriad Rivers Merging,"
  by Fujibayashi Yasutake, 1676
• Shōninki — "The True Value of the Ninja,"
  by Natori Sanjurō Masazumi, 1681
• Shinobi Hiden, better known as Ninpiden — "The Hidden Traditions of the Ninja,"
  by Hattori Hanzo and others, 1560

On the sources: The period manuals cited above are available today in the modern English translations of Antony Cummins and Yoshie Minami: Bansenshūkai as The Book of Ninja (2013), Shōninki as True Path of the Ninja (2011), Ninpiden / Shinobi Hiden as The Secret Traditions of the Shinobi (2012); the commentaries of Chikamatsu Shigenori appeared in the Book of Samurai series. Japanese terms and names are given in the standard (Hepburn) romanization.