The origins of the ninja or shinobi, as they were called in the past, is surrounded by mystery and legend. One cannot think of ninja without evoking images of black clad warriors running over roof tops and committing acts of subterfuge, espionage or assassination. 

The truth is rather less mystical and fantastic. 

The word 'ninja' is often used in a modern context, but historically the word 'shinobi' was used mainly in official texts. There were however many names for those who used stealth and subterfuge.

Although there were recorded clans of shinobi in the Iga and Koga regions, these groups only emerged later in Japan's history. In general, the word shinobi did not refer to a specific group or warrior caste, but was a way to describe a person who was involved in certain activities. 

A Samurai involved in an assassination attempt would be referred to as a shinobi (someone involved in subterfuge); a farmer being conscripted as a guide and tracker by a feudal lord would be called a shinobi; a bandit in the mountains attacking caravans would be called a shinobi; a thief in the night would be described as a shinobi; even religious men were called shinobi during one era or another. 

It was a catch-all term for describing an individual and their activities, much like we would use the term 'terrorist' today to describe individuals involved in despicable acts. But just as governments today use their intelligence agencies and military to commit acts of terror to achieve one goal or another, so did those in power in Feudal Japan use everyday people to commit acts that were against the moral and ethical codes of the time. 

In feudal Japan the Samurai followed the code of Bushido on the surface, which put them above the peasants and merchants as a figure of moral and governmental authority, but under the cover of darkness these Samurai used the same despicable acts (or hired others to do it for them) as everyone else to achieve their goals.   

Shinobi in Japanese history represent the anathema of society. Those who acted against the law, against the ethics and morals of the time, and those who were often targeted as a scapegoat when those in power had to misdirect lines of inquiry. 

Even though shinobi was used to describe people in this way, there were many other people labeled as shinobi who were not assassins, thieves or spies. Like other cultures around the world there have been groups in Japan that have been oppressed or victimised. When these groups fled and or hid, or started lives away from civilisation they were also often described as shinobi. 

The nin 忍 in ninja 忍者 or shinobi 忍び means stealth, but it also means to endure. In fact the verb shinobu 忍ぶ means to hide oneself or to endure something.

The core tenant of shinobi and ninjutsu is to survive and this is also a core value of Ikari Dōjō. The nin 忍 in ninjutsu 忍術 means to be patient, but it also means to endure and to hide until the time is right. These principles are what Ikari Dōjō represents within its training and teachings. 

This is the spirit of the shinobi.