History

Due to the fact that the ninja rarely left anything in writing or boasted of their achievements, the history of the ninja is shrouded in secrecy, so the great majority of stories circulating about them are difficult to prove. Minamoto no Yoshitsune, who employed surprise as a major weapon in his victories, is said in a popular folktale to have been educated by a Tengu to learn the tactic and became a ninja. In truth, he was taught by Buddhist monks who educated him with Chinese books like The Art of War.

One of the earliest roots of ninja, Togakure-ryu, reportedly originated in the late Heian era. Iga and Ko¯ga are two of the most famous ninja styles, and are often pitted against each other in fiction. In reality, they were allies and worked together in mutual defense pacts. Both of these claim that they originate in the Heian period.

Only a few records remain from the Kamakura period. Kusunoki Masashige used some clever tactics against enemies that remotely resemble ninja tactics. From the Muromachi period there are even fewer records. Both of these times were generally peaceful, and many battles had tournament-like aspects that barred a surprise attack. Somewhere in these time periods, bushido began to form as the proper and honorable way a samurai must follow. It would be well into Edo period that bushido was finally formalized and until then ninpo¯ was not well separated from bushido.

In the Sengoku Period, also known as the Warring States period, ninja flourished as a war was often determined by how well warlords collected information. Almost all famous daimyo had ninja, or a ninja-like group under his control and they served as their eyes and ears, sometimes as their hands. Some daimyo¯ were reportedly ninja themselves. The clan of Sanada, the most famous member being Sanada Yukimura, was reportedly a ninja clan. This is widely agreed due to the successful defense of their castle with only around 3,000 against an overwhelming force of 50,000 led by Tokugawa Hidetada. Their amazing tactics, complete with splitting the house in two, each supporting Toyotomi and Tokugawa in order to survive no matter which side finally won, has given them a legendary status. Later, they would come to be called Sanada Ju Yushi, lit.

Ten heroes under Sanada, in fictions where they used ninja skills to defeat everything but their jealous wives who would, of course be ninja themselves.
Tokugawa Ieyasu used ninja well, controlling both Iga and Koga in unifying and ultimately rising to the rank of Shogun. In his dramatic escape through the mountainous landscape of Nara after Oda's assassination, Iga ninja led by Hattori Hanzo helped Ieyasu escape, gaining his favor. The last battle where ninja reportedly fought is in the Siege of Shimabara under the Tokugawa shogunate. As the shogunate became stable, ninja were effectively unemployed.

Some became Oniwabanshu, a semi-secret group of bodyguards and intelligence officers who worked tending gardens of the Edo castle and eavesdropping on unaware daimyo. A ninja master Fujibayashi Sabuji wrote Bansenshukai as collections of ninja knowledge. Yet most knowledge was still passed on by the oral method and by training as most ninja believed that their service would soon be needed once again. The peace of the Edo period would continue for over 200 years.

In the Edo period, ninja became popular heroes in books and plays. Many mythical ninja powers such as becoming invisible, jumping over tall fences, casting spells and calling up a giant toad larger than a human, were all invented in these fictitious accounts of ninja. Ninja did not correct these misconstructions and some may have even written these stories themselves to increase their value should their services have become needed. One of the lesser-known contributions made by ninja is their involvement in furthering the research of fireworks.

At the end of the Edo period, the ninja's service was once again needed. Ninja were called up to accompany delegates that met ambassadors from abroad. Some of them may have secretly been involved in servicing these ambassadors. With this, almost all records end.