The first saboteurs
Little is known about the early emergence of Japanese spies. This uncertainty stems in part from social divisions of the time, with many accounts coming from noble samurai circles even as myths hint at lower-class voices. The Kojiki, a collection from the early 8th century, recounts Yamato Takeru, a youth who disguised himself as a beautiful girl to ambush two leaders of the Kumaso. While this is one of the earliest passages suggesting sabotage, it does not clearly align with later ninja traditions or any specific written code of stealthy deception.
Only in the 14th century epic Taiheiki does a tale appear of a master shinobi who supposedly burned an entire enemy stronghold. By the 15th century, shinobi entered broader use. The term came to describe a defined group of professional mercenaries. Feudal lords employed them as spies, arsonists, organizers of minor covert operations, and even terrorists. They sometimes acted as hired agitators who would stir the populace to revolt against opponents.
For ancient Japan, the line between samurai and shinobi was never crossed in the same way it has been in other cultures. The noble code of honor among the Japanese aristocracy allowed surprise attacks in some contexts, but the samurai were expected to engage in open battle. They did not typically cloak themselves in civilian clothing or move through cities at night in disguise.
professional spies
Ninja lineages were organized into clans, with Iga and Koka among the most famous. These areas cover what is now Mie Prefecture and Koka County, chosen for their rugged, secluded valleys ideal for training. Villages dedicated to ninjutsu training emerged here because the terrain shielded them from easy access. The ninja clans supplied many daimyo, allowing Iga and Koka to gain significant autonomy during the latter part of the medieval era.
The great majority of ninjas were born into Iga or Koka families and received intensive, ongoing instruction from childhood in arts that would later be called ninjutsu. Training encompassed classical combat skills, stealth movement, endurance running, and climbing. Future shinobi were also schooled in the use of poisons and early gunpowder techniques.
Techniques were often categorized by natural elements. For example, in a fire-focused approach a warrior might ignite a flame to draw guards away from infiltrated areas. A tree technique taught climbing and concealment among branches, while a stone technique described rolling into a compact form to blend with stony surroundings.
During many missions ninjas avoided the iconic cinematic wardrobe, instead choosing inconspicuous appearances. They could blend in as priests, artists, fortune tellers, merchants, ronin, or monks. They favored dark tones at night and wore ordinary clothing by day. Entry tools included rope hooks, crampon boots, wall-piercing trowels, and saws for making passages through barriers. Poised to adapt, their toolkit often balanced practicality with cunning improvisation.
One Russian researcher notes a typical loadout that might include a farmer’s hat, a small kit of medicines, writing implements for notes and passes, and a bamboo vessel filled with hot coals for starting small fires.
The Rise and Fall of the Ninja
The primary role of the ninja was reconnaissance. They gathered intelligence about terrain, structures, and communications, with some accounts describing them as specialists who could intrude into hidden spaces and observe from within. The Noti no Kagami is often cited as mentioning their origins in Iga and Koga and recognizing their ability to slip into enemy fortifications while remaining indistinguishable as outsiders.
Second to reconnaissance stood sabotage missions. An example recounts a campaign against Savoyama Castle, where a tactic involved stealing a family crest lantern, fabricating multiple copies, and using the lanterns to enter the castle before causing a blaze. This illustrates the blend of infiltration and deliberate destruction.
Ninja activity also played a role during the Sengoku Jidai, the Age of Warring States. After the Battle of Okehazama in 1560, Tokugawa Ieyasu employed a squad of eighty ninjas from the Koga clan to challenge the Imagawa forces. One assault involved breaking into a fortress, igniting its towers, and taking the life of the commander along with hundreds of soldiers.
The last widely documented ninja engagement occurred during the Shimabara Rebellion in 1637–1638, when ninjas aided suppression of a Christian uprising. After the Meiji Restoration, political and military shifts reduced the active roles for shinobi. Some former practitioners transitioned to other careers in public service or private enterprise, while others faced diminished opportunities. The Oniwaban service was created under the Tokugawa shogunate to handle intelligence tasks, and many former shinobi found work beyond combat, including roles in medicine, craftsmanship, and commerce, with some turning to theft as needed.
One figure often cited as the last living bearer of the shinobi tradition is Jin’ichi Kawakami, once director of the Ninja Museum in Iga-Ueno. He reportedly declined sharing details with students, noting that during civil strife and the Edo era, ninja skills could be useful, yet modern equipment like guns, contemporary medicine, and the internet have altered the landscape so dramatically that ninjutsu has little place today.
In the contemporary era, Japan’s Self-Defense Forces maintain a Special Forces Group that echoes some historical duties of shinobi but with training aligned to modern, overseas programs. The martial legends of ninjas persist in novels, films, and video games, but practical demonstrations of ninjutsu are rare. Some instructors claim to teach hand-to-hand practices inspired by ninja lore, though such connections lack rigorous evidence beyond myth and fiction. (Attributed in historical summaries.)