Ninja

In the fifteenth and sixteenth centuries both regions were controlled by networks of small landholding families. The Iga league and the Kōka league governed through councils and bound their members to mutual defence. Contemporary diaries report warriors from Iga and Kōka hired for night attacks and castle raids in the wars around Kyoto.

In the Tenshō Iga War, Oda Nobunaga's forces invaded Iga, were repelled in 1579 and returned in overwhelming strength in 1581, devastating the province. After Nobunaga's death in 1582, Tokugawa Ieyasu escaped from the Kansai region back to his home province by crossing the mountains of Iga and Kōka with the help of local men, the so-called Iga-goe. This service tied Iga and Kōka men to the Tokugawa house.

Historical records show shinobi as practical specialists: they gathered intelligence, carried messages, infiltrated enemy territory in disguise, set fires, stood guard and scouted before battles. In the Shimabara Rebellion of 1637–38, records describe men from Kōka sent to reconnoitre the rebels' castle at Hara. Their skills relied on knowledge of terrain, weather, fire, medicine and human psychology rather than supernatural powers.

The main written sources on ninjutsu are manuals compiled in the Edo period, after the wars had ended, to preserve and legitimise the knowledge. The Bansenshūkai (1676), attributed to Fujibayashi of Iga, is the most comprehensive, covering strategy, infiltration, tools and astronomy; the Shōninki (1681) of the Kishū domain focuses on mindset and methods. Surviving objects and houses, such as the Kōka-ryū Ninjutsu Yashiki, a former residence with hidden rooms, are held up as evidence, though many popular tools and techniques are later inventions.

Under the Tokugawa shogunate, groups of Iga and Kōka men were employed in Edo as guards, for example at the gates and inner parts of Edo Castle, and in minor police and security functions. Hattori Hanzō Masanari, a Tokugawa commander of Iga descent who led the Iga men, gave his name to the Hanzōmon gate of the castle and the Hanzōmon subway line. Many feudal domains retained men with shinobi skills for surveillance.

The eighth shōgun, Tokugawa Yoshimune, created the oniwaban in 1716, a body of trusted agents from his home domain of Kishū who gathered information on officials and domains. By this time the role had become that of a hereditary low-ranking official, and the fighting shinobi of the civil-war era belonged to the past.

The ninja of popular imagination took shape in Edo-period kabuki, ukiyo-e and illustrated books, where they appear as sorcerers using magic toads, disappearing in smoke. The black costume may owe more to the convention of black-clad, 'invisible' kabuki stage assistants than to historical practice. In the 1910s the Tachikawa Bunko storybooks made the ninja hero Sarutobi Sasuke famous, and in the late 1950s and 1960s a ninja boom followed in novels such as Yamada Fūtarō's Kōga Ninpōchō, films and manga.

The James Bond film You Only Live Twice (1967) and Hollywood films of the 1980s spread the figure worldwide, followed by the Teenage Mutant Ninja Turtles and the manga and anime Naruto. Research is now pursued seriously: Mie University established a centre for ninja studies in 2017, the same year Iga and Kōka were recognised together as Japan Heritage. Both towns have ninja museums and preserved houses and celebrate the ninja with festivals.