Ninja (professional spy in feudal Japan highly trained in stealth and secrecy) (忍者)

Ninja is a name of individual or group who served daimyo (Japanese territorial lord) or feudal lord doing intelligence activities and assassinations from the Kamakura period to Edo period in Japan.
Ninja is well known not only in Japan, but also in the world


Ninja was a group who was mainly doing covert operations for a feudal lord. Their position was different from that of samurai or ashigaru (common foot soldier).

They are often described as "dressed in solid black", "wearing kusari-katabira (chain woven protective wear) inside and paint their face with black ink", "carrying a sword on the back" or "break into the enemy territory under cover of darkness", but a figure in black costume can be seen in the night, thus it is considered that their costume was dark blue or persimmon color. Most of the existing costumes which are considered to be "ninja costume" are persimmon color or similar colors. There is a theory that it was cheaper to make the costume in persimmon color than in black. There is a theory that the ninja costume was made based on the working clothe used in Koga gun (county) region (present-day southeastern Shiga Prefecture) and Iga Province region (present-day western Mie Prefecture). They didn't wear "exclusive" costume, but appropriately dressed for the situation (in the town, dressed like townspeople and when they broke into a residence, dressed like a servant), and there is a theory that people believed that ninja was wearing black costume because ninja in kabuki was described as "invisible presence" like kuroko (stage assistants dressed in black).

Since they focused on escaping rather than fighting, usually they didn't wear heavy kusari-katabira to be as nimble as possible. While kusari-katabira was drawn simply in the comic expression, it developed a design of character who wear a mesh shirt. The sword carried on the back encumbered their move, they normally belted a sword on. However, when they crawled under floor, they carried a sword on the back to move easily in the narrow space and used it as a shield. They conducted various special trainings and had special tools, the tools are called "Ningu" and the various techniques including art of escaping are called "Ninjutsu".

There are two types of ninjutsu, "Innin" and "Yonin". Innin is a way of seeking an inside information and sabotaging by breaking into the enemy territory concealing themselves, the appearance of ninja which generally people imagine is of this situation. On the other hand, yonin is a way of accomplishing a purpose with a trick exposing themselves to the public. So-called intelligence, conspiracy and dividing operation are included. Some kobujutsu (old manners of martial art) still have traces of ninjutsu.

A recent study shows that ninja was a group of engineers who had abundant knowledge of animals and plants, and chemistry as well as a group of intelligence agents who had great physical ability and were strictly disciplined.

Ninja was divided into ranks such as Jonin (high-ranking ninja), Chunin (middle-ranking ninja) and Genin (low-ranking ninja). In Iga, Jonin were goshi (country samurai) or jizamurai (local samurai) and as landlords, they controlled Genin who were kosakunin (tenant farmer). Chunin were kogashira (head of an organizational section) leading Genin. In Koga, the highest rank was not Jonin, but Chunin. It is said that the daimyo (Japanese territorial lord) in the Sengoku period around the country actually hired Genin. The Iga school excelled in individual activities, while the Koga school excelled in group activities.

Before the war, their general name was "Ninjutsu-tsukai (master of ninjutsu)", but after the war, they were generally called "Ninja", "Shinobi no mono", "Shinobi" through the works of Tomoyoshi MURAYAMA, Sanpei SHIRATO and Ryotaro SHIBA. It is said that in the Asuka period, Prince Shotoku used OTOMO no Hosohito as "Shinobi (志能備)". His job was to spy on dominant Gozoku (local ruling family) such as Soga clan.

Until the Edo period, there was no standardized name for ninja and it varied in each region, for example, there were name such as "Rappa", "Suppa (素破) (the origin of a slang word "Suppanuki" meaning divulgation)", "Suppa (水破)", "Suppa (出抜)", "Toppa (突破)", "Toppa (透破)", "Ukagami", "Dakko", "Kusa", "Nokizaru", "Kyodo", "Kyodan", "Monomi", "Kanshi", "Kikimonoyaku", "Arukimiko", "Kamari" and "Hayamichi no mono".

Currently, female ninja is generally called "Kunoichi" (the origin of this code name was a Japanese character "女" meaning woman, and it is considered that this character was broken down into three characters "く (ku)", "ノ (no)" and "一 (ichi")). There is another theory that the origin of "Kunoichi" was the number of holes in human body, women have an additional hole to nine holes such as nose, eye, ear, navel and anus (nose is counted as one hole). However, the numeration varies by materials (for example, urinary meatus is counted instead of navel) and it is not so credible. Also, there is a theory that the name "Kunoichi" itself was a creation by Futaro YAMADA. Although there are some ninjutsu using female ninja called "the art of Kunoichi", it is said that female ninja who appears in video picture or comic didn't exist. However, there is a description that a female ninja snaked into the castle masquerading as a housemaid and it is considered that she used "women's gossip" for the intelligence activity and created considerable performance. Famous kunoichi appeared in historical fact is a group of arukimiko who served Shingen TAKEDA. For details, refer to the section of Kunoichi.

Origin and transition

There are several theories about the origin of ninja. They formed some groups in regions around Japan. Particularly, groups of ninja which were based in Koga and Iga were famous. In these locations, there were many ninja houses and they conducted daily training. Since most territories of Koga and Iga were shoen (manor in medieval Japan) in the Kamakura period, they were not controlled by shugo (provincial constable) or jito (manager and lord of manor), but when the shoen system collapsed in the Sengoku period (in Japan), dozens of jizamurai groups struggled for power. It is considered that "Ninjutsu" arose spontaneously in the condition that each jizamurai always fought an information war and a guerrilla war to maintain power.

Description in Mikawa Monogatari which was written by Hikozaemon OKUBO
It is described that IeyasuTOKUGAWA became independent from the Imagawa clan after the Battle of Okehazama and took over Nishinokori-jo Castle (Also known as Kaminogo-jo Castle) of Nagamochi UDONO in Gamagori City using ninja during the war for regaining Mikawa Province. The letter sent from Koga bushi in Omi Province to the bugyo (magistrate) in 1667 describes the achievement of Koganijuikke (twenty one families of Koga school) that they came as support arms and decapitated Totaro UDONO by night raid and fire-setting. It should be noted that it was not Iga but Koga.

Legend of the Hattori clan

In 1962, "kamijima-ke bunsho (Documents of the Kamijima family)(a manuscript copied in the end of the Edo period) " was found at an old household in Ueno city. According to the document, the third son of Gensei UESHIMA who was a member of the Hattori clan in Iga Province was an actor of Sarugaku (form of theater becoming the basis for Noh), Kanami and his mother was a sister of Masashige KUSUNOKI. In other words, Kanami was a nephew of Masashige KUSUNOKI. There is no specific reason, but it is called a false family record. Zeami who was a son of Kanami also said, "My ancestor is the Hattori clan".

In Iga Province, three families of Jonin, the Fujibayashi clan, the Momochi clan and the Hattori clan controlled other jizamurai and adopted collegial system to form the area not controlled by daimyo (Japanese territorial lord) in the Sengoku Period. They united and fought against invasion from outside, when Nobunaga ODA sent Katsutoshi TAKIGAWA, a Chikujo Bugyo (magistrate of building a castle), Katsutoshi TAKIGAWA to control Iga Province, they dismissed him, and also eliminated Nobukatsu ODA's army who invaded in retribution (the first Tensho Iga War). When Nobunaga schemed a conspiracy with a part of enemy and invaded again with a great army, the other groups of ninja in Iga Province suffered catastrophic damage (the second Tensho Iga War). It is said that Tanba MOMOCHI and other one hundred ninja fled down to Negoro, Kishu Province.

Under the feudal system characteristic of the Tokugawa shogunate

Iga ninja started to be hired by Edo bakufu (Japanese feudal government headed by a shogun) because when Ieyasu TOKUGAWA visited Sakai (present-day Sakai City, Osaka Prefecture) for sightseeing at the time of Honnoji Incident, they escorted and helped him to pass through Iga Province. In particular, Masanari HATTORI was treated preferentially and one of the gate of Edo-jo Castle was named after him and it still remains as a geographical name of Tokyo, "Hanzomon". As well as seeking inside information of territorial lords for the Tokugawa shogunate, they kept peace of the Edo-jo castle town as doshin (a police constable) by handling surveys near the Edo-jo Castle, guard of O-oku (the inner halls of Edo Castle where the wife of the Shogun and her servants reside) and management of vacant residences. Oniwaban (the shogunate's guard of the inner garden) is often considered to be same as ninja, but it is a misunderstanding, actually Yoshimune TOKUGAWA, the eighth shogun just classified Kusurigomeyaku (the predecessor of oniwaban) whom he brought from Kishu Province into the same rank with Igamono, oniwaban is not related to ninja (for details, refer to the section of Oniwaban).

When Iemitsu TOKUGAWA ruled, roju (member of shogun's council of elders) (Nobutsuna MATSUDAIRA, Tadaaki ABE and Masamori HOTTA) and sobashu (aide of the shogun) (Masamori NAKANE) forced the government by the military. As a result, increased ronin (masterless samurai) emerged as a social issue and major events (uprisings)such as Shimabara War and Keian Incident (Shosetsu YUI).

At the time of Shimabara War and Keian Incident, Masamori NAKANE sent about 20 yoriki (a police sergeant) to several places around and made them investigate details.

Also, there is a record that when Shimabara War occurred, a squad of Koga ninja sneaked into Hara-jo Castle where rioters barricaded themselves and found the fact that rioters' provisions were running out.

TAIRA no Tadamasa who was descended from the Taira clan and the Hattori clan were relatives and Nakane was an uncle of Masashige HATTORI (the fourth Hanzo HATTORI) who fell from power because of the involvement in Okubo Nagayasu Incident. For this reason, the theory that Nakane was a ninja was formed.

A haikai poet, Basho MATSUO who walked across provinces in the Edo period was from an area which is present-day Iga City, Mie Prefecture. Thus, there is a theory that Basho MATSUO was actually a ninja or a spy and it is used as a subject of novels and so on. The fact that it is physically difficult for 47 years old man to travel tens of kilometers per day as described in his book "the Narrow Road to the Deep North" was used as the basis for the theory. An ukiyoe artist, Hokusai KATSUSHIKA who lived in the Edo period is also considered to have been a kogi-onmitsu (shogunate spy). These theories have no crucial foundation and are just works of imagination for now.

Rinzo MAMIYA, an explorer in the Edo period, was a spy of the shogunate and it may be said that he was a ninja in the broad sense. At least his action that he betrayed Kageyasu TAKAHASHI in the Siebold Incident was criticized from a Confucian moral standpoint and described as a typical action of cruel ninja.

When Kurofune (the Black Ships) led by Commodore Matthew PERRY arrived off the coast of Urawa, the shogunate spy acted for investigation and it was the last activity of so-called ninja.

Ninja after the Meiji period

In Meiji period, the administration was transferred to new Meiji Government and Japanese army and navy were created through modernization policy, then ninja lost their job. It is said that after ninja lost the scene of their activities, they got new jobs such as farmers, policemen, pyrotechnicians with special skills of using fire, doctors or pharmacists with knowledge of medicine. Since the said arrival of Kurofune, the existence of ninja had been forgotten, but ninja started to be featured in novels and period dramas from late 1950 and they have come to be recognized among Japanese again.


Ningu is a weapon or an instrument which ninja uses.

Kaginawa (hooked rope)

Kunai (ninja throwing knives)

Kunai is written as "苦無"or "苦内" in Japanese.

Shuriken (small throwing blade)

Shuriken is a throwing blade. The shape ranges from stick, crisscross to round. Usually, ninja carried one or at most three or four shuriken.

Ninto (ninja sword)

Makibishi (spiked caltrops used by ninja)

Makibishi which was made of seeds was edible.

Five colored rice

It was rice colored in red, blue, yellow, black and purple. It was not edible, but used as communication code between associates.

Ninja costume

It was a costume altered working clothe for fighting and it was not black but more like brown in order to lurk in the night. Sometimes, "Rokushaku Tenugui (Japanese towel which is 1.818 meters in length) " was used for a mask.


It is a skill which ninja used to run away from chasers.

Gosha no jutsu (five verbal skills to control other person psychologically)
They are five verbal skills to control other person psychologically in conversation.

Kisha no jutsu
It is a skill to praise other person and watch for a chance.

Dosha no jutsu
It is a skill to make other person angry and lose its coolness.

Aisha no jutsu
It is a skill to raise sympathy.

Rakusha no jutsu
It is a skill to make other person envy and lose its will to fight. If circumstances allow, it will be able to gain over the opponent.

Kyosha no jutsu
It is a skill to play on other person's fear by using superstition and so on and make him/her lose its will to fight.

Tonjutsu (ninja art of escape)
It is a skill to make enemies stuck when ninja runs away from them. In particular, katon (a tonjutsu using fire), suiton (a tonjutsu using water), doton (a tonjutsu using dirt), mokuton (a tonjutsu using tree) and kinton (a tonjutsu using valuable article) are called goton (five tonjutsu).

Katon no jutsu
Suiton no jutsu
Doton no jutsu
Mokuton no jutsu
Kinton no jutsu
It is a skill to run away by scattering valuable articles. If enemies scramble for the articles, it would be successful.

Chujuton no jutsu (a tonjutsu using insects and animals)

Tenda no jutsu (a skill to feed the enemy's spy disinformation)
Shishishinchu no jutsu
Ninja hachimon (eight compulsory subjects to become a ninja)
(Masaaki HATSUMI says that ninja hachimon are compulsory subjects to be a ninja regardless of the school.)
Koppo jutsu (a martial art with bare hands)
Kiai jutsu (a ninjutsu using vital energy)
Shuriken jutsu (art of shuriken)
Ka jutsu (art of fire)
So jutsu (art of spearmanship)
Art for amusement
Kyomon (knowledge, culture and art of warfare)

Prominent ninja

Existent ninja
Even though an actual person, they have both substantial and virtual sides.


The Heian period


The Sengoku period (period of warring states), Igamono (generic name of local samurai in Iga Province)

Morikiyo IDEURA

The Sengoku period

Sasuke KOZUKI (Shimotsuge no Kizaru)

He was a model for a member of Sanada Juyushi (Sanada ten braves), Sasuke SARUTOBI.


He was a model for a member of Sanada Juyushi, Saizo KIRIGAKURE.

Danzo KATO (also called Tobi KATO, which means flying KATO, or kite KATO), the Sengoku period


The Sengoku period. Toppa. Koshu school

Yasunaga HATTORI

The Sengoku period. Igamono. The first Hanzo HATTORI

Masanari HATTORI

A son of Hanzo Yasunaga HATTORI
The second Hanzo HATTORI
A hatamoto (a direct vassal of the shogun) of Tokugawa family. Technically, he was not a ninja, but he controlled Iga ninja.

Masashige HATTORI

The second son of Masanari Hanzo HATTORI
He fell from power because of the involvement in Okubo Nagayasu Incident. Later, he was hired by the lord of Kuwana Domain, Sadatsuna MATSUDAIRA (a son of Sadakatsu) and the family of Hanzo HATTORI persisted in Kuwana Domain.

Kotaro FUMA

The Sengoku period. He served the Hojo family.
Fuma Party

Nagatonokami FUJIBAYASHI

The Sengoku period. He was one of the three major Jonins in Iga Province


The Sengoku period. Birth year:unknown -158. He was an actual person who was a model of imaginary person, Sandayu MOMOCHI

Yanosaburo HACHIYA

The Sengoku period. Hachiyashu (group of performers). He served the Amago family.

Toranosuke AOYAMA

A ninja of Koga school
He served Ieyasu TOKUGAWA.

Masahide ITAGAKI (板垣昌秀)
He was a ninja who flourished mainly in present-day Yamagata Prefecture. Masami OKANO (岡野正美) and Kimihiko OSAWA (大沢公彦) were his disciples.

He served Katsutoyo YAMAUCHI.

Emperor Tenmu

Aritsune TOYOTA stated the theory that Emperor Tenmu was a ninja because he was familiar with tenmon tonko (a type of fortune-telling). Generally, "tenmon tonko" is interpreted as a fortune-telling not a ninjutsu.


He was a member of Negoroshu (a group of armed priests in Negoro-ji Temple) and failed to shoot at Nobunaga ODA.


The Sengoku period. An illusionist


He was described as a ninja in the historical novel "Shingen TAKEDA" written by Jiro NITTA.


Although he was a haikai poet from Iga Province, there is a theory that he was an Iga ninja.


He was a kogi-onmitsu and known for the great achievement that he sneaked into the Kagoshima-jo Castle in Satsuma Domain and engraved his name on cycad trees in the castle.

Masamori NAKANE

He served Hidetada TOKUGAWA, the second shogunate, and became a sobashu and ometsuke (chief inspector of the Edo shogunate) of Iemitsu TOKUGAWA, the third shogunate through the positions of oban (a group of guards in the Edo shogunate) and konando (steward to the shogun). He was a shogun's retainer and Iki no kuni no Kami (Governor of Iki Province). There is a theory that he was a boss of kogi-onmitsu.

Today's successors of ninjutsu
He was a successor of Koga school and the fourteenth headmaster of Koga school ninjutsu. He was called "the last ninja" and lived until middle of the Showa period.

He claims he is a successor of Banke Shinobi no Den (a type of ninjutsu) of Koga school and the twenty-first headmaster of Koga school.

He claims he is the thirty-fourth successor of Togakushi school.

There are a very few martial artists who claim they are handing down ninjutsu to posterity.

[Original Japanese]