skills required of the ninja has come to be known in modern times as ninjutsu, but it is unlikely they were previously named under a single discipline. Modern misconceptions have identified ninjutsu as a form of combat art, but historically, ninjutsu largely covered espionage and survival skills. Some lineage styles (ryūha) of ninjutsu such as Togakure-ryū are claimed to be descended from historical practices.


This diagram from the Bansenshukai uses divination and esoteric cosmology (onmyōdō) to instruct on the ideal time for taking certain actions.The first specialized training began in the mid-15th century, when certain samurai families started to focus on covert warfare, including espionage and assassination.[57] Like the samurai, ninja were born into the profession, where traditions were kept in, and passed down through the family.[20] According to Turnbull, the ninja was trained from childhood, as was also common in samurai families. Outside the expected martial art disciplines, a youth studied survival and scouting techniques, as well as information regarding poisons and explosives.[58] Physical training was also important, which involved long distance runs, climbing, stealth methods of walking[59] and swimming.[60] A certain degree of knowledge regarding common professions was also required if one was expected to take their form in disguise.[58] Some evidence of medical training can be derived from one account, where an Iga ninja provided first-aid to Ii Naomasa, who was injured by gunfire in the Battle of Sekigahara. Here the ninja reportedly gave Naomasa a "black medicine" meant to stop bleeding.[61]

With the fall of the Iga and Kōga clans, daimyos could no longer recruit professional ninjas, and were forced to train their own shinobi. The shinobi was considered a real profession, as demonstrated in the bakufu's 1649 law on military service, which declared that only daimyos with an income of over 10,000 koku were allowed to retain shinobi.[62] In the two centuries that followed, a number of ninjutsu manuals were written by descendants of Hattori Hanzō as well as members of the Fujibayashi clan, an offshoot of the Hattori. Major examples include the Ninpiden (1655), the Bansenshukai (1675), and the Shōninki (1681).[6]

Some practitioners of modern ninjutsu include Stephen K. Hayes and Masaaki Hatsumi, who is the head (sōke) of Bujinkan, a martial arts organization based in Japan. However, the link between modern interpretations of ninjutsu and historical practices is a matter of debate.

Tactics
The ninja did not always work alone. Teamwork techniques exist: for example, in order to scale a wall, a group of ninja may carry each other on their backs, or provide a human platform to assist an individual in reaching greater heights.[63] The Mikawa Go Fudoki gives an account where a coordinated team of attackers used passwords to communicate. The account also gives a case of deception, where the attackers dressed in the same clothes as the defenders, causing much confusion.[28] When a retreat was needed during the Siege of Osaka, ninja were commanded to fire upon friendly troops from behind, causing the troops to charge backwards in order to attack a perceived enemy. This tactic was used again later on as a method of crowd dispersal.[30]

Most ninjutsu techniques recorded in scrolls and manuals revolve around ways to avoid detection, and methods of escape.[6] These techniques were loosely grouped under corresponding natural elements. Some examples are:

Hitsuke - The practice of distracting guards by starting a fire away from the ninja's planned point of entry. Falls under "fire techniques" (katon-no-jutsu).[64]
Tanuki-gakure - The practice of climbing a tree and camouflaging oneself within the foliage. Falls under "wood techniques" (mokuton-no-jutsu).[64]
Ukigusa-gakure - The practice of throwing duckweed over water in order to conceal underwater movement. Falls under "water techniques" (suiton-no-jutsu).[64]
Uzura-gakure - The practice of curling into a ball and remaining motionless in order to appear like a stone. Falls under "earth techniques" (doton-no-jutsu).[64]
Disguises

A komusō monk is one of many possible disguises.The use of disguises is common and well documented. Disguises came in the form of priests, entertainers, fortune tellers, merchants, rōnin, and monks.[65] The Buke Myōmokushō states,

Shinobi-monomi were people used in secret ways, and their duties were to go into the mountains and disguise themselves as firewood gatherers to discover and acquire the news about an enemy's territory ... they were particularly expert at travelling in disguise.[24]
A mountain ascetic (yamabushi) attire facilitated travel, as they were common and could travel freely between political boundaries. The loose robes of Buddhist priests also allowed concealed weapons, such as the tantō.[66] Minstrel or sarugaku outfits could have allowed the ninja to spy in enemy buildings without rousing suspicion. Disguises as a komusō, a mendicant monk known for playing the shakuhachi, were also effective, as the large "basket" hats traditionally worn by them concealed the head completely.[67]




Equipment
Ninjas utilized a large variety of tools and weaponry, some of which were commonly known, but others were more specialized. Most were tools used in the infiltration of castles. A wide range of specialized equipment is described and illustrated in the 17th century Bansenshukai,[68] including climbing equipment, extending spears,[61] rocket-propelled arrows,[69] and small collapsible boats.[70]

Outerwear

A suit of armor purportedly worn by ninjasWhile the image of a ninja clad in black garbs (shinobi shōzoku) is prevalent in popular media, there is no written evidence for such a costume.[71] Instead, it was much more common for the ninja to be disguised as civilians. The popular notion of black clothing is likely rooted in artistic convention. Early drawings of ninjas were shown to be dressed in black in order to portray a sense of invisibility.[3] This convention was an idea borrowed from the puppet handlers of bunraku theater, who dressed in total black in an effort to simulate props moving independently of their controls.[72] Despite the lack of hard evidence, it has been put forward by some authorities that black robes, perhaps slightly tainted with red to hide bloodstains, was indeed the sensible garment of choice for infiltration.[3]

Clothing used was similar to that of the samurai, but loose garments (such as leggings) were tucked into trousers or secured with belts. The tenugui, a piece of cloth also used in martial arts, had many functions. It could be used to cover the face, form a belt, or assist in climbing.

The historicity of armor specifically made for ninjas cannot be ascertained. While pieces of light armor purportedly worn by ninjas exist and date to the right time, there is no hard evidence of their use in ninja operations. Depictions of famous persons later deemed ninjas often show them in samurai armor. Existing examples of purported ninja armor feature lamellar or ring mail, and were designed to be worn under the regular garb. Shin and arm guards, along with metal-reinforced hoods are also speculated to make up the ninja's armor.[3]

Tools

A page from the Ninpiden, showing a tool for breaking locks.Tools used for infiltration and espionage are some of the most abundant artifacts related to the ninja. Ropes and grappling hooks were common, and were tied to the belt.[68] A collapsible ladder is illustrated in the Bansenshukai, featuring spikes at both ends to anchor the ladder.[73] Spiked or hooked climbing gear worn on the hands and feet also doubled as weapons.[74] Other implements include chisels, hammers, drills, picks and so forth.

The kunai was a heavy pointed tool, possibly derived from the Japanese masonry trowel, to which it closely resembles. Although it is often portrayed in popular culture as a weapon, the kunai was primarily used for gouging holes in walls.[75] Knives and small saws (hamagari) were also used to create holes in buildings, where they served as a foothold or a passage of entry.[76] A portable listening device (saoto hikigane) was used to eavesdrop on conversations and detect sounds.[77]

The mizugumo was a set of wooden shoes supposedly allowing the ninja to walk on water.[70] They were meant to work by distributing the wearer's weight over the shoes' wide bottom surface. The word mizugumo is derived from the native name for the Japanese water spider (Argyroneta aquatica japonica). The mizugumo was featured on the show Mythbusters, where it was demonstrated unfit for walking on water. The ukidari, a similar footwear for walking on water, also existed in the form of a round bucket, but was probably quite unstable.[78] Inflatable skins and breathing tubes allowed the ninja to stay underwater for longer periods of time.[79]

Despite the large array of tools available to the ninja, the Bansenshukai warns one not to be overburdened with equipment, stating "...a successful ninja is one who uses but one tool for multiple tasks".[80]

Weaponry
Although shorter swords and daggers were used, the katana was probably the ninja's weapon of choice, and was sometimes carried on the back.[67] The katana had several uses beyond normal combat. In dark places, the scabbard could be extended out of the sword, and used as a long probing device.[81] The sword could also be laid against the wall, where the ninja could use the sword guard (tsuba) to gain a higher foothold.[82] The katana could even be used as a device to stun enemies before attacking them, by putting a combination of red pepper, dirt or dust, and iron filings into the area near the top of the scabbard, so that as the sword was drawn the concoction would fly into the enemies eyes, stunning him until a lethal blow could be made. While straightswords were used before the invention of the katana,[83] the straight ninjatō has no historical precedent and is likely a modern invention.


A pair of kusarigama, on display in Iwakuni CastleAn array of darts, spikes, knives, and sharp, star-shaped discs were known collectively as shuriken. While not exclusive to the ninja,[84] they were an important part of the arsenal, where they could be thrown in any direction.[85] Bow were used for sharpshooting, and some ninjas bows were intentionally made smaller than the traditional yumi (longbow).[86] The chain and sickle (kusarigama) was also used by the ninja.[87] This weapon consisted of a weight on one end of a chain, and a sickle (kama) on the other. The weight was swung to injure or disable an opponent, and the sickle used to kill at close range. Simple gardening tools such as Kunai and sickles were used as weaponry so that if discovered a ninja could claim they are his tools and not weapons, despite their ability to be used in battle.

Explosives introduced from China were known in Japan by the time of the Mongol Invasions (13th century).[88] Later, explosives such as hand-held bombs and grenades were adopted by the ninja.[79] Soft-cased bombs were designed to release smoke or poison gas, along with fragmentation explosives packed with iron or pottery shrapnel.[63]

Along with common weapons, a large assortment of miscellaneous arms were associated with the ninja. Some examples include poison,[68] caltrops,[89] cane swords (shikomizue),[90] land mines,[91] blowguns, poisoned darts, acid-spurting tubes, and firearms.[79] The happō, a small eggshell filled with blinding powder (metsubushi), was also used to facilitate escape.[92]

Legendary abilities
Superhuman or supernatural powers were often associated with the ninja. Some legends include flight, invisibility, shapeshifting, the ability to "split" into multiple bodies, the summoning of animals, and control over the five classical elements. These fabulous notions have stemmed from popular imagination regarding the ninja's mysterious status, as well as romantic ideas found in later Japanese arts of the Edo period. Magical powers were sometimes rooted in the ninja's own efforts to disseminate fanciful information. For example, Nakagawa Shoshujin, the 17th century founder of Nakagawa-ryū, claimed in his own writings (Okufuji Monogatari) that he had the ability to transform into birds and animals.[62]

Perceived control over the elements may be grounded in real tactics, which were categorized by association with forces of nature. For example, the practice of starting fires in order to cover a ninja's trail falls under katon-no-jutsu ("fire techniques").[89]


Actor portraying Nikki Danjō, a villain from the kabuki play Sendai Hagi. Shown with hands in a kuji-in seal, which allows him to transform into a giant rat. Woodblock print on paper. Kunisada, 1857.The ninja's adaption of kites in espionage and warfare is another subject of legends. Accounts exist of ninjas being lifted into the air by kites, where they flew over hostile terrain and descended into, or dropped bombs on enemy territory.[70] Kites were indeed used in Japanese warfare, but mostly for the purpose of sending messages and relaying signals.[93] Turnbull suggests that kites lifting a man into midair might have been technically feasible, but states that the use of kites to form a human "hang glider" falls squarely in the realm of fantasy.[94] However, references to man-lifting kites exist in works dating to the relevant era and before, including Sun Tzu's The Art of War.

Kuji-kiri
Kuji-kiri is an esoteric practice which, when performed with an array of hand "seals" (kuji-in), was meant to allow the ninja to enact superhuman feats.

The kuji ("nine characters") is a concept originating from Taoism, where it was a string of nine words used in charms and incantations.[95] In China, this tradition mixed with Buddhist beliefs, assigning each of the nine words to a Buddhist deity. The kuji may have arrived in Japan via Buddhism,[96] where it flourished within Shugendō.[97] Here too, each word in the kuji was associated with Buddhist deities, animals from Taoist mythology, and later, Shinto kami.[98] The mudrā, a series of hand symbols representing different Buddhas, was applied to the kuji by Buddhists, possibly through the esoteric Mikkyō teachings.[99] The yamabushi ascetics of Shugendō adopted this practice, using the hand gestures in spiritual, healing, and exorcism rituals.[100] Later, the use of kuji passed onto certain bujutsu (martial arts) and ninjutsu schools, where it was said to have many purposes.[101] The application of kuji to produce a desired effect was called "cutting" (kiri) the kuji. Intended effects range from physical and mental concentration, to more incredible claims about rendering an opponent immobile, or even the casting of magical spells.[102] These legends were captured in popular culture, which interpreted the kuji-kiri as a precursor to magical acts.

Famous people
Many famous people in Japanese history have been associated or identified as ninjas, but their status as ninja are difficult to prove and may be the product of later imagination. Rumors surrounding famous warriors, such as Kusunoki Masashige or Minamoto no Yoshitsune sometimes describe them as ninjas, but there is little evidence for these claims. Some well known examples include:


Kumawakamaru escapes his pursuers by swinging across the moat on a bamboo.[103] Woodblock print on paper. Kuniyoshi, 1842-1843.Mochizuki Chiyome (16th cent.) - The wife of Mochizuke Moritoki. Chiyome created a school for girls, which taught skills required of geisha, as well as espionage skills.[104]
Fujibayashi Nagato (16th cent.) - Considered to be one of three "greatest" Iga jōnin, the other two being Hattori Hanzō and Momochi Sandayū. Fujibayashi's descendents wrote and edited the Bansenshukai.
Fūma Kotarō (d. 1603) - A ninja rumored to have killed Hattori Hanzō, with whom he was supposedly rivals. The fictional weapon Fūma shuriken is named after him.
Hattori Hanzō (1542–1596) - A samurai serving under Tokugawa Ieyasu. His ancestry in Iga province, along with ninjutsu manuals published by his descendants have led some sources to define him as a ninja.[105] This depiction is also common in popular culture.
Ishikawa Goemon (1558–1594) - Goemon reputedly tried to drip poison from a thread into Oda Nobunaga's mouth through a hiding spot in the ceiling,[106] but many fanciful tales exist about Goemon, and this story cannot be confirmed.
Kumawakamaru (13th-14th cent.) - A youth whose exiled father was ordered to death by the monk Homma Saburō. Kumakawa took his revenge by sneaking into Homma's room while he was asleep, and assassinating him with his own sword.[107]
Momochi Sandayū (16th cent.) - A leader of the Iga ninja clans, who supposedly perished during Oda Nobunaga's attack on Iga province. There is some belief that he escaped death and lived as a farmer in Kii Province.[108] Momochi is also a branch of the Hattori clan.
Yagyū Muneyoshi (1529–1606) - A renowned swordsman of the Shinkage-ryū school. Muneyoshi's grandson, Jubei Muneyoshi, told tales of his grandfather's status as a ninja.[41