Ninja
The word ninja appears in written records as far back as the late 8th century within poems found in the Man'yōshū. A specific poem from that era reads "Yorozu yo ni / Kokoro ha tokete / Waga seko ga / Tsumishi te mitsutsu / Shinobi kanetsumo". The underlying connotation of shinobi means to steal away or to hide, which extends to forbearance and stealth. Mono translates simply to a person, creating the phrase shinobi-no-mono for those who operate in secret. Historical documents rarely used the term ninja itself, preferring regional colloquialisms instead. These included monomi meaning one who sees, nokizaru meaning macaque on the roof, and rappa meaning ruffian. Iga-mono described someone originating from the province of Iga. In modern fiction, kunoichi serves as another word specifically for female practitioners. This term supposedly derives from three strokes forming the kanji character: ku, no, and ichi. English speakers often leave the plural unchanged as ninja, reflecting the Japanese language's lack of grammatical number.
Antecedents to the ninja may have existed as early as the 12th century during periods of unrest in Japan. Prince Shotoku lived from 574 to 622 AD and is believed to have employed a spy named Otomono Sahito. Records take place at an early stage of Japanese history but are unlikely connected to later accounts. The first recorded use of espionage occurred under Prince Shōtoku in the 6th century. A boy spy named Hasetsukabe no Koharumaru was killed for spying against Taira no Masakado according to the 10th-century Shōmonki. Daisuke Togakure lost his lands after being defeated in a regional conflict around 1162. He traveled to mountains in southwest Honshu where he met Kain Doshi, a Chinese warrior-monk. They formulated guerilla tactics called ninjutsu which became counter-culture to the time. Daisuke abandoned bushido to work with Doshi on these new methods. His descendants founded the first ninja school known as Togakureryu. By the Sengoku period, shinobi had roles including scout, surprise attacker, and agitator.
The Iga and Kōga clans were jizamurai families living in Iga Province and adjacent Kōka District. Villages devoted to training ninja appeared from these regions due to their remoteness and mountainous terrain. Professional ninjas were actively hired by daimyōs between 1485 and 1581. The Iga professionals were sought after for siege warfare skills called shirotori. Leading families established de facto independence from their shugo by the 1460s. The Kōka ikki persisted until 1574 when forced to become vassals of Oda Nobunaga. The Iga ikki continued until 1581 when Nobunaga invaded and wiped out organized clans. Survivors fled to mountains or arrived before Tokugawa Ieyasu who treated them well. Hattori Hanzō later served as Tokugawa's bodyguard following the conquest. An alliance between Iga and Kōka was formalized around 1560 in a constitutional document. Following the Battle of Okehazama in 1560, Tokugawa employed eighty Kōga ninja led by Tomo Sukesada. They raided an Imagawa clan outpost setting fire to towers and killing two hundred garrison members.
Arson served as the primary form of sabotage practiced by ninja targeting castles and camps. Rokkaku Yoshikata hired ninjas in 1558 to set fire to Sawayama Castle using deception techniques. A chūnin captain led forty-eight men into the castle stealing lanterns bearing enemy crests. This bakemono-jutsu allowed entry without fighting before setting fires to the structure. In 1561 commanders under Kizawa Nagamasa hired three genin rank ninja for Maibara fortress. The mercenary shinobi threatened to abandon operations unless allowed independent strategy execution. Fire eventually enabled capture of the fortress during chaotic rushes. Countermeasures included weapons concealed in lavatories or under removable floorboards. Buildings featured traps and trip wires attached to alarm bells. Nijō Castle in Kyoto utilized nightingale floors resting on metal hinges designed to squeak loudly when walked upon. Grounds covered with gravel provided early notice of intruders while segregated buildings contained fires better. Himeji Castle exemplified winding routes leading to inner compounds with blind spots for surveillance.
After the Shimabara Rebellion ended in 1638, almost no major wars occurred until the bakumatsu era. Ninja had to earn living by employment from Han governments or changing professions entirely. Many lords hired them as bodyguards or spies rather than battlefield combatants. Tsu, Hirosaki, and Saga domains continued employing their own ninja into the bakumatsu period though numbers remain unknown. Former ninja became doctors, medicine sellers, merchants, martial artists, and fireworks manufacturers. Some unemployed individuals turned to banditry like Fūma Kotarō and Ishikawa Goemon. A diary kept by Matsudaira clan members described reconnaissance actions taken by Kōga ninja during the rebellion. The Ukai diary details how ninja captured enemy provisions and infiltrated castles at night obtaining secret passwords. These written accounts represent the final mention of ninja in war before fading into obscurity under Tokugawa rule.
Between 1960 and 2010 artifacts dating to the Siege of Odawara were uncovered believed to be ninja weapons. Archaeologist Iwata Akihiro stated flat throwing stones stopped enemy movement while clay caltrops prevented castle invasions. Mie University founded the world's first research center devoted to ninja in 2017 located in Iga Province. A graduate master course opened in 2018 with approximately three student enrollments per year. Students must pass admission tests about Japanese history reading historical documents. On the 19th of June 2022, Kōka city announced discovery of Kanrinseiyo copies found in Kazuraki Shrine warehouses. This handwritten reproduction produced in 1748 describes forty-eight types of ninjutsu including methods for attaching cotton layers to straw sandals. It clarifies manufacturing techniques for cane swords and makibishi caltrops used historically. Scientific researchers study ancient documents applying them to modern contexts through interdisciplinary scholarship.
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Common questions
When did the word ninja first appear in written records?
The word ninja appears in written records as far back as the late 8th century within poems found in the Man'yōshū. A specific poem from that era reads Yorozu yo ni Kokoro ha tokete Waga seko ga Tsumishi te mitsutsu Shinobi kanetsumo.
Who founded the first ninja school known as Togakureryu?
Daisuke Togakure lost his lands after being defeated in a regional conflict around 1162 and traveled to mountains in southwest Honshu where he met Kain Doshi. They formulated guerilla tactics called ninjutsu which became counter-culture to the time, and his descendants founded the first ninja school known as Togakureryu.
What happened to the Iga and Kōka clans during the Sengoku period?
Leading families established de facto independence from their shugo by the 1460s before the Kōka ikki persisted until 1574 when forced to become vassals of Oda Nobunaga. The Iga ikki continued until 1581 when Nobunaga invaded and wiped out organized clans, causing survivors to flee to mountains or arrive before Tokugawa Ieyasu who treated them well.
How did ninja conduct arson attacks on castles like Sawayama Castle?
Rokkaku Yoshikata hired ninjas in 1558 to set fire to Sawayama Castle using deception techniques where a chūnin captain led forty-eight men into the castle stealing lanterns bearing enemy crests. This bakemono-jutsu allowed entry without fighting before setting fires to the structure, enabling capture of the fortress during chaotic rushes.
When were artifacts dating to the Siege of Odawara uncovered?
Between 1960 and 2010 artifacts dating to the Siege of Odawara were uncovered believed to be ninja weapons. Archaeologist Iwata Akihiro stated flat throwing stones stopped enemy movement while clay caltrops prevented castle invasions.