Japanese Ninjas

What we know about Ninja?

In the Sengoku period, they were referred to by a variety of names, but not "Ninja". "Ninja" is an Edo period term. The two characters, "Nin" and "Ja" are the same characaters as "Shinobi" and "mono". One of the original terms was "Shinobo no mono"--literally, person of stealth. Someone in the Edo period decided this was too much of a mouthful, so used the Sinified readings of the two characters and presto, you've got "N". Prior to the Edo period, the word was not used. Shinobi, or Shinobi no mono, was one term. "Kusa" was a very common term also, used to denote stealthy scouts. Visit Japanese culture articles for more readings.