The Art of Ninjutsu
According to the Bansenshukai
The Bansenshukai (万川集海, "Ten Thousand Rivers Flowing into the Sea") is an essential treatise on ninjutsu, compiled in 1676 by Fujibayashi Yasutake (藤林保武), a renowned strategist and ninja leader from the Iga region. This text represents one of the most comprehensive and systematic works on ninjutsu and feudal Japan's military tactics, covering topics from infiltration techniques to the philosophical and ethical principles that guide the ninja's path.
Written during the first years of Edo period (1603–1868), the Bansenshukai reflects not only the martial traditions of the Iga and Kōga ninja clans but also the historical context of its time. Under the Tokugawa shogunate, Japan experienced a period of relative peace, which reduced the need for traditional warfare tactics, including ninja activities. This context allowed for the codification and preservation of ninjutsu knowledge, not as an active practice but as a historical and cultural legacy.
Fujibayashi Yasutake, a prominent figure among the Iga ninja, sought to compile the accumulated knowledge of generations into a single document. His aim was not only to preserve techniques and strategies but also to convey the ethical and philosophical values that characterized true ninjutsu practitioners. While Yasutake's figure is not widely documented in general historical records, he is regarded as one of the key compilers of ninja teachings, thanks to his efforts to organize and document knowledge that had previously been transmitted orally or through fragmented writings.
The Bansenshukai consists of 22 volumes divided into chapters that cover a wide range of topics related to ninjutsu and military strategy. These include:
Techniques of infiltration and sabotage.
The use of specific tools and weapons for ninjas.
Principles of espionage, psychological manipulation, and political sabotage.
Philosophical and ethical aspects of ninjutsu, emphasizing moral rectitude.
Practical knowledge on survival, meteorology, and environmental use.
The text combines technical, pragmatic, and philosophical elements, establishing ninjutsu not merely as a martial skill but as an ethical and strategic path deeply rooted in the needs of feudal Japan.
Today, several copies of the Bansenshukai are known to exist, preserved in academic institutions and private collections in Japan. One of the most famous copies is housed in the library of Ueno City, Mie Prefecture, the region where the Iga ninja clans flourished. Other manuscript versions, with slight variations in content, have also been identified, suggesting that the text was transmitted and adapted according to the needs of different clans or historical contexts.
The preservation of these copies is largely due to the efforts of Japanese historians and academics to document Japan's martial and strategic traditions, especially during the Meiji period (1868–1912), when there was a drive to systematize historical knowledge following the nation's modernization.
In Japanese academic circles, the Bansenshukai has been the subject of numerous historical and anthropological studies. Universities such as Mie University and Kyoto University have conducted detailed research on the text, focusing on the technical, cultural, and philosophical aspects of ninjutsu. These studies have revealed that the Bansenshukai is not only a manual of strategy but also a reflection of the social, political, and spiritual concerns of feudal Japan.
For instance, research by Mie University has analyzed how the Bansenshukai incorporates Taoist and Buddhist concepts to justify the ethics of ninjutsu. Other studies have explored the text’s relevance in Japanese military literature and its connection to works like Sun Tzu's The Art of War and Taigong Wang’s Liutao (Six Secret Teachings).
Additionally, digitization and translation projects have been undertaken to make the Bansenshukai accessible to an international audience, highlighting its significance not only in Japanese historical contexts but also in the global study of strategy and philosophy.
The Bansenshukai is not merely a manual of espionage and combat techniques but a masterpiece that combines strategy, ethics, and philosophy. Its creation by Fujibayashi Yasutake during the Edo period represents a monumental effort to preserve an endangered art. Modern academic studies continue to uncover its depth and relevance, showing how this text not only defined ninjutsu but also its place in Japan's history and culture.
Ninjutsu Mondō: Questions and Answers on the Ninja's Path
Through a section of questions and answers known as Ninjutsu Mondō (忍術問答), the Bansenshukai delves into the essence of ninjutsu, exploring its origins, role in military strategy, and ethical principles.
Ninjutsu’s roots run deep in the ancient military traditions of China. While its exact origin is not documented, it is believed to have emerged during the reigns of Emperor Fuxi and Emperor Huangdi, who established the first military laws. In Japan, ninjutsu formally began during Emperor Tenmu's reign (673–686), when infiltration tactics were used to capture enemy fortresses. This event, recorded in the Nihon Shoki (日本書記), marks the start of ninjutsu's development as an essential strategic tool for warfare.
In military strategy, ninjutsu serves as the core that allows commanders to understand the enemy's weaknesses, anticipate their movements, and exploit any gaps to ensure victory. Unlike regular scouts who observe from afar, ninjas infiltrate deep into enemy territory. Their missions include not only gathering precise information about fortresses and troops but also creating discord, sabotaging resources, and facilitating conditions for successful attacks. Without this capacity for infiltration and espionage, military strategies would lack a solid foundation for success.
Although ninjutsu originated in China, where it was referred to by various terms like kan (spies) or chō (secret agents), in Japan, it adopted a deeper meaning with the term shinobi. Composed of the characters for "blade" and "heart," this term reflects the determination and sharpness needed to carry out ninjutsu missions. This linguistic distinction highlights not only the evolution of ninjutsu in Japan but also its transformation into a philosophical art centered on internal discipline and moral purpose.
Regions like Iga and Kōga became preeminent centers of excellence for ninjutsu. During the Muromachi period, these areas lacked centralized governance, prompting their inhabitants to develop advanced defensive and espionage skills to protect their territories. Their ninjas excelled in infiltration and sabotage, even defeating larger forces such as those led by Oda Nobunaga. These regions became pivotal examples of how the necessity for survival evolved into a strategic and efficient art.
The Bansenshukai mentions eleven initial masters of ninjutsu, including legendary figures like Nomura no Ōi Magodaiyū and Tateoka no Dōjun. Dōjun's style, in particular, gave rise to 48 additional schools, resulting in 49 traditions within Iga and Kōga. These masters and their styles not only defined ninjutsu as an art but also diversified it to adapt to different situations and contexts.
A true ninja master, known as jo no shinobi (superior shinobi), is characterized by their anonymity and discretion. A master ninja achieves their objectives undetected, blending seamlessly with the natural flow of events. Their success is not attributed to their skills but is perceived as the work of fate or chance. This ability to remain invisible, both literally and figuratively, defines a true master of ninjutsu.
The Bansenshukai presents ninjutsu as more than a set of technical skills. It is a philosophy of life that demands integrity, patience, and a deep understanding of the environment. Ninjas operate in harmony with the natural flow of events, achieving great victories without seeking credit. This art is based on absolute discretion, where success is measured not by recognition but by the ability to act with precision, undetected. Even in times of peace, ninjutsu remains relevant as a reminder of the importance of strategy, discipline, and moral purpose.
By integrating ethical principles with strategic techniques, ninjutsu rises as a tool of wisdom and action. The Bansenshukai remains an essential guide to understanding this ancient art, emphasizing its impact not only on military history but also on the character and philosophy of its practitioners.
「問」中国えは名を改めて呼んでいるが、我国では忍びと名付けた理由は何。 「答」中国では間諜、遊偵、細作、遊士、行人などと呼ぶ理由は先に述べた通りであり、敵の隙を突いて潜入したり君臣を中違いさせたりする職という理由から付けられた名である。しかしきれらは皆、忍術の未梢の理由で命名されたものである。我国では「忍び」であり、これは「刃の心」という字で構成され、忍術の本質を穿った命名である。この意味を熟考しなれば、忍術の本源は理解出来ない。
Question: Although in China names are modified to describe spies, why are they called shinobi in Japan?
Answer: In China, terms such as kanchō (間諜, spy), yūtei (遊偵, itinerant scout), saisaku (細作, infiltrator), yūshi (遊士, wandering man), and kōjin (行人, traveler) are used for reasons previously explained, as they describe professions associated with infiltrating enemy vulnerabilities, sowing discord among rulers and vassals, or performing similar tasks. However, these names all originate from partial functions of ninjutsu and do not encompass its full essence.
In Japan, the term shinobi (忍び) was adopted, composed of the characters 刃 (ha, blade) and 心 (kokoro, heart or mind), forming a word that profoundly reflects the essential nature of ninjutsu. This name encapsulates its true meaning, which must be carefully meditated upon to understand the very root of ninjutsu. Without this reflection, it is impossible to fully grasp the origin and essence of this art.