On this Wikipedia the language links are at the top of the page across from ninja foodi grill recipes article title. Drawing of the archetypical ninja from a series of sketches by Hokusai.

In the unrest of the Sengoku period, mercenaries and spies for hire became active in Iga Province and the adjacent area around the village of Kōga. It is from these areas that much of the knowledge regarding the ninja is drawn. Ninja figured prominently in legend and folklore, where they were associated with legendary abilities such as invisibility, walking on water and control over natural elements. The word shinobi appears in the written record as far back as the late 8th century in poems in the Man’yōshū. Historically, the word ninja was not in common use, and a variety of regional colloquialisms evolved to describe what would later be dubbed ninja.

In fiction written in the modern era kunoichi means “female ninja”. World War II culture, possibly because it was more comfortable for Western speakers. Despite many popular folktales, historical accounts of the ninja are scarce. Historian Stephen Turnbull asserts that the ninja were mostly recruited from the lower class, and therefore little literary interest was taken in them. So-called ninjutsu techniques, in short are the skills of shinobi-no-jutsu and shinobijutsu, which have the aims of ensuring that one’s opponent does not know of one’s existence, and for which there was special training. However, some ninjutsu books described specifically what tactics ninja should use to fight, and the scenarios a ninja might find themselves can be deduced from those tactics.

Yamato Takeru dressed as a maidservant, preparing to kill the Kumaso leaders. The title ninja has sometimes been attributed retrospectively to the semi-legendary 4th-century prince Yamato Takeru. It was not until the 15th century that spies were specially trained for their purpose. It was around this time that the word shinobi appeared to define and clearly identify ninja as a secretive group of agents. Amongst the samurai, a sense of ritual and decorum was observed, where one was expected to fight or duel openly.

The plains of Iga, nested in secluded mountains, gave rise to villages specialized in the training of ninja. There was a retainer of the family of Kawai Aki-no-kami of Iga, of pre-eminent skill in shinobi, and consequently for generations the name of people from Iga became established. Inside the camp at Magari of the shōgun Yoshihisa there were shinobi whose names were famous throughout the land. A distinction is to be made between the ninja from these areas, and commoners or samurai hired as spies or mercenaries. Unlike their counterparts, the Iga and Kōga clans produced professional ninja, specifically trained for their roles. Following the Battle of Okehazama in 1560, Tokugawa employed a group of eighty Kōga ninja, led by Tomo Sukesada.

They were tasked to raid an outpost of the Imagawa clan. The Ukai diary, written by a descendant of Ukai Kanemon, has several entries describing the reconnaissance actions taken by the Kōga. Suspecting that the castle’s supplies might be running low, the siege commander Matsudaira Nobutsuna ordered a raid on the castle’s provisions. Here, the Kōga captured bags of enemy provisions, and infiltrated the castle by night, obtaining secret passwords. We dispersed spies who were prepared to die inside Hara castle. Arakawa Shichirobei and Mochizuki Yo’emon met extreme resistance and suffered from their serious wounds for 40 days.

As the siege went on, the extreme shortage of food later reduced the defenders to eating moss and grass. This desperation would mount to futile charges by the rebels, where they were eventually defeated by the shogunate army. With the fall of Hara Castle, the Shimabara Rebellion came to an end, and Christianity in Japan was forced underground. These written accounts are the last mention of ninja in war. After the Shimabara Rebellion, there were almost no major wars or battles until the bakumatsu era.

Many lords still hired ninja, not for battle but as bodyguards or spies. Their duties included spying on other domains, guarding the daimyō, and fire patrol. Many former ninja were employed as security guards by the Tokugawa shogunate, though the role of espionage was transferred to newly created organizations like the Onmitsu and the Oniwaban. Ninja were spies and saboteurs and likely participated in the siege. Mie University founded the world’s first research centre devoted to the ninja in 2017.

A graduate master course opened in 2018. There are approximately 3 student enrollments per year. Students must pass an admission test about Japanese history and be able to read historical ninja documents. In 2020, the 45-year-old Genichi Mitsuhashi was the first student to graduate from the master course of ninja studies at Mie University.