In Search of the Ninja Quotes

“A ninja or shinobi is a mixture of spy, guerrilla tactician, night time infiltration agent, explosives expert, thief and arsonist. The ninja have been named in various ways in many parts of Japan, however, historically they were known as ‘shinobi’ before they became ninja. Both of the names ‘shinobi’ (also shinobi no mono) and ninja come, in the main, from the same combination of Chinese ideograms , which can be read in the two ways described above. It is a misconception that the ninja are a separate force outside of the samurai, as they are in fact a subgroup of the samurai with some members being from the foot soldier or Ashigaru class; this will be discussed in depth later in this volume. A ninja could come from any class in Japan but many were low level samurai retainers.”
― Antony Cummins, In Search of the Ninja: The Historical Truth of Ninjutsu