It has been stated by academics that the ninja (忍者) are a misrepresented phenomenon. Some writers assert that peasant ninja-clans are the work of romantic fiction and Ninjitsu as an art is a modern invention. Those who practice Ninjitsu object to this, and refer to certain historical texts that served as training manuals (such as the ‘Banshenkukai’ and the ‘Ninpinden’), as providing the legitimacy for claiming a continuous line of knowledge transmission from the past to present day.
From an independent viewpoint, evidence strongly supports the notion that “ninja” is simply a term that was sometimes ascribed to spies and covert military operatives throughout Japanese history. It is by no means an exclusive term either; other terms found within historical literature include Kyodan, Mitsumono, Shinobi, Yato, Monomi, Rappa, Kussa, Nokizaru and Suppa, all of which describe the same or similar type of person. In fact, ninja as a term is scarcely found in Japanese historical documents.
Whatever the true history of covert operatives in Japanese history may be, what is interesting for Okinawan martial artists is that many of the weapons associated with the “modern ninja” are also found within the practice of Kobudo. Is this simply because the ninja are proposed to have been peasants and therefore would have characteristically used non-military tools and weapons? Or could there be some connection between Okinawan martial artists and the Shogunate spies?
All writers agree that covert military techniques in Japanese history appear to have their origin outside of Japan and many point their fingers towards China as the source. This is predominantly due to the influence of Chinese military authors such as Jiang Ziya (姜子牙) and Sun Tzu (孫子) who specifically identify methods for selecting and training covert operatives in their writings. However there is also another area of consideration, the islands of Ryukyu.
Ninja are classically associated with the Edo period (1603-1867), this is when they first start to appear in artwork, become more prevalent in literature and their legend most often dramatised. This is precisely the period during which the Ryukyu kingdom was attacked, Okinawa was invaded (1609) and subsequently assimilated into the wider Japanese political landscape. It is well discussed that Okinawan martial arts were at their zenith during this period in history and firmly established that their fighting techniques and strategies were heavily influenced by the Chinese.
There are some Okinawan martial artists who reputedly claim their ancestors were employed by Japanese generals due to their martial arts skill. There are also Japanese who claim descent from ninja clans who also have links with Okinawa. If we observe traditional Okinawan dress we can see many similarities between this clothing and Edo period depictions of ninja. Perhaps most implicating however, is that the traditional weapons of Okinawa Kobudo are those associated with the ninja.
Ed: Nowhere in translated literature has the link between the “Ninja” and Okinawa been made. Though this area is significantly under researched, to the best of the author’s knowledge, it has never been witnessed, documented nor asserted.